Draft Surveyors

Hague
22nd March 2007, 19:45
Peter MacAllister.
Does anyone remember Peter who was the Draft Surveyor at Port Talbot in the early/mid 70s.
Peter used a device for reading the draft which consisted of a 3' length of clear plastic tube (ID2") a reducer valve/tap coupled to another clear plastic tube of similar length but reduced ID. The device was fitted with a spare magnetron attached to it uppermost part. When close to the draft mark he would submerge the whole device and then place (if loaded) or throw (if light) the device at the draft mark. He could get an excellent draft in any swell and all those who have visited Port Talbot will be aware of the swell that can be experienced. The oscillation of the water in the tube would be millimeteres and hence the reading he obtained was recorded as e.g.48' 06.5" (Yes peter insisted on half an inch.
Before any SA tells us that the mean of means allows for inaccuracies don't bother. We all know.
The point I am making is Peter's professionalism and love of his work.
Brgds

eldersuk
22nd March 2007, 22:35
We used to lend the mate a boiler gauge glass for the same purpose.

Derek

John Cassels
23rd March 2007, 10:19
Yes , remember Peter well. Also sailed with his son Willie MacAllister when
he was Master on the Naess pioneer 1969 and before he went ashore as
super for Denholms.

JC

Pilot mac
23rd March 2007, 12:31
Hague,
Mean of Means, double means or triple means? I dont know if there has ever been a standard for draft surveys but in my experience there seem to be many diferent versions. My first trip as mate was with a Master determined to squeeze every gram of cargo into the ship and I quickly learnt to 'hog' the ship to maximise cargo. The Jebsen R class would hog easily with the two empty deep tanks midships, In excess of 10cm was the norm.

regards
Dave

Hague
23rd March 2007, 18:51
Hague,
Mean of Means, double means or triple means? I dont know if there has ever been a standard for draft surveys but in my experience there seem to be many diferent versions. My first trip as mate was with a Master determined to squeeze every gram of cargo into the ship and I quickly learnt to 'hog' the ship to maximise cargo. The Jebsen R class would hog easily with the two empty deep tanks midships, In excess of 10cm was the norm.

regards
Dave

Dave,
Sounds like Capt Tony (G) to me.
Not forgetting that these vessels had Norwegian Loadlines which were utilised on the Norwegian Coast. Hence, these 5,790.00 DWCC vessel's could and frequently did load ( quite legally) inxs of 6,150 Tonnes from Leirpollen ( I bet you and Laqkercapt haven't heard that name in a while.) The inside passage was utilised. Happy days. Especially April through October. Somewhere, I have a photo of the 'Rocknes' in Tana Fjord having just left Leirpollen enroute Honningvaag for bunkers. (6,230 M/Tonnes out turn in Odda). Virtually no freeboard but still manageing 15kts.

randcmackenzie
23rd March 2007, 21:31
Yes , remember Peter well. Also sailed with his son Willie MacAllister when
he was Master on the Naess pioneer 1969 and before he went ashore as
super for Denholms.

JC

Hi john - Peter was actually Willie's older brother. Quite a bit older.

I knew Willie quite well, great guy.

He died a few years ago, I don't know if Peter is still around or not.

Best Regards,
Roddie.

Hague
23rd March 2007, 21:50
Over about 6/7 consecutive voyages (around '74) I managed to reduce the 'DWT Constant' down from around 1600 tonnes to the 'book' 340 tonnes due to Peters persistance and keen measurement. Used to put abt a foot of wb in one of the DBTks on the Sepitiba Bay Ballast leg and really agitate the mud and it soon came out.
One of lifes 'gentlemen', even though he gave me the wrong directions at the Hirwaun Roundabout for the (483) and thence home. I ended up in Abergavenny.

HENNEGANOL
23rd March 2007, 21:56
Forgive my ignorance as an engineer, but in my days at sea the draught was spelt DRAUGHT not draft, which was used with regard to National Service or the drawing office.

Gerry.

Pilot mac
23rd March 2007, 22:11
Hague,
can you remember the constant for the R boats when you were there?
Dave

Hague
23rd March 2007, 22:20
Hague,
can you remember the constant for the R boats when you were there?
Dave

Dave,
You will have to give me a little time on that one(I'm sure you know)
Hague

Hague
23rd March 2007, 22:48
Forgive my ignorance as an engineer, but in my days at sea the draught was spelt DRAUGHT not draft, which was used with regard to National Service or the drawing office.

Gerry.

Good evening Gerry,
Whenever I have noted the word Draught as you have suggested it has always had forced, induced and natural connectations. 'Forced Draught Job' also used as discourteous description of people of a large disposition.
Draft in the context I have used is quite correct. If not they better start re-writing all the DR Derrett (Ship Stability) and Nicholls Concise Guides from the late 50s when I started.
But maybe there is another thread in this somewhere.
In the 'China Boats' when on the lookout we used to give 'one bell to Port' 'two to Stbd and three dead ahead). In ALL other companies which I sailed with post 'china' it was the opposite way around. One to Stbd, Two to Port and Three Dead Ahead. Reference to this was made in Sea Breeze, no less, several years ago by the then Chief Examiner of Masters and Mates (himself an ex 'China Boat Man)
Brgds

K urgess
23rd March 2007, 23:26
According to "Nicholls's Seamanship and Nautical Knowledge" 22nd edition, 1966. The official log entries record "Draught" and freeboard. But the ship plan in the back shows it as "Draft" in the deadweight scale.
You pays yer money and you takes yer choice.[=P]

On page 2 -
"The lookoutman is stationed on the forecastle-head or in a crows-nest on the foremast and, like the man at the wheel, he usually does a two hours' "trick." When the lookoutman sights a light on the starboard bow he usually intimates the fact by one stroke on the bell, two strokes for a light on the port bow, and three strokes when it is sighted right ahead. He may supplement this signal by calling out the fact to the officer on the bridge."

More useless facts a sparkie is not supposed to know or bother himself about(Jester)

John Cassels
24th March 2007, 09:24
Hi john - Peter was actually Willie's older brother. Quite a bit older.

I knew Willie quite well, great guy.

He died a few years ago, I don't know if Peter is still around or not.

Best Regards,
Roddie.

Roddie; Didn't know that , always thought that Willie was Peter's son.
Also was not aware that Willie passed away. Could tell a few storys about
that 8 months on the N Pioneer with Willie as Master. Great times !!.

JC

John Cassels
24th March 2007, 09:29
Over about 6/7 consecutive voyages (around '74) I managed to reduce the 'DWT Constant' down from around 1600 tonnes to the 'book' 340 tonnes due to Peters persistance and keen measurement. Used to put abt a foot of wb in one of the DBTks on the Sepitiba Bay Ballast leg and really agitate the mud and it soon came out.
One of lifes 'gentlemen', even though he gave me the wrong directions at the Hirwaun Roundabout for the (483) and thence home. I ended up in Abergavenny.


Always used to do that as routine , swill wash ballast tanks especially
DB's. The rougher the weather the better was the result.

JC

Hague
24th March 2007, 09:41
Always used to do that as routine , swill wash ballast tanks especially
DB's. The rougher the weather the better was the result.

JC

John,
Quite agree. The results could be remarkable. On my final voyage into Port Talbot ( after 14 months onboard) I managed to Discharge abt 105,000 which had crept up from abt 101/102k from when the vessel first entered T/C with Bisco in 72. I also exceeded the arrival draft (if I may spell it that way) of 48'.
Familiarity breeds contempt.
Brgds

John Cassels
27th March 2007, 09:19
Draft surveys , what an emotive subject. Most of us will have our own ideas
about them - mine are rather laconic , having done quite a few over the years.
The best example I can give of how ludicrous they could be were the ones
carried out on cargoes of high grade zinc concentrates by the recievers
surveyor in Antwerp. This little guy was the image of Hercule Poirot of Agatha
Christie fame and always insisted that the carrier /owners rep ( me ) was
present. We used to stand on the quay and try to read the marks through
the driving rain and guaging the slop of water to get a reading. After expending so much effort to read the inboard drafts , the 3rd.mate was sent
to read the outboard marks because he was to portly to climb the ladder or
use a boat. HO , DO and LO figs were used from the cheng, tanks never even
sounded let alone being checked for temp or SG. Ballast tanks were sounded
but always accepted when told they were dry , he was never even close
enough to hear of the rod hit the striker plate or not.
Then after half an hour or so of humming and hawing , sucking of pencils
and gnashing of teeth , this guy would proudly announce his outurn figure to
the nearest 10 kilos. And , remarkably , his figure was always very close to
the B/L fig. ( on which the freight was paid anyhow).

Have never met a surveyor yet who checked that the K was correct as given. Or one who did a spot check against the tank tables to check that
the sounding pipes had not been tampered with ( on a chartered bulk carrier,
I one found a centre DB where the bottom 2" of the sounding pipe had been
cropped off and an extra 2" striker plate fitted.
And what about the old trick of filling the ballast main ? . Tanks showed dry
but a full ballast main could gain you 300 tonnes or so.

This subject must produce some discussion , so lets have it guys . lets hear it for the --draft survey --.

JC

Pilot mac
27th March 2007, 10:52
John,
not just the ballast main but also chain locker and duct keel. Was on a 40,000 tonner where No 6 DB's had a residual 120 tonne still within when sounding indicated 'dry' yet was never detected by any draft surveyor. The assumption was dry tank, empty tank. I have however worked with many that have checked K by doing two surveys.

regards
Dave

Hague
27th March 2007, 14:15
John/Dave,
Another 'trick' used was on the Cape/Panamax vessel with direct overside discharge of the TSTks. Arrival at the disport with say +500m/t in aftermost TSTk (P&S). After the Draft Survey the 3/Off or similar would open the valves.
In the period of getting back onboard, seeking the C/Eng for his figs and then commencing the sounding from the Fore Peak (for some obscure reason). The aftermost TSTk were MT by the time you got down aft. One new what was going on but you could never catch them.

John Cassels
27th March 2007, 18:33
Hague and Dave. Thanks your inputs , had hoped you two would respond.
I would never think of questioning the professionalism of gentlemen such
as Peter Mac ( 1st post in this thread) , my point is that with lesser mortals,
a draft survey can be just a farce in most cases. For example , a surveyor
can make a big play of reading draft marks down to fantastic degrees of
accuracy and then does not even check if water shows on the chalk mark.
Our earlier discussion re mud in DB's ( even saw a surveyor remark - when
the sounding rod came up with the bottom 6" covered in mud - oh tank dry,
OK without asking the made what effect this had on the constant).
Plenty of "tricks "examples , teaspoonful of galley salt in the demsity bucket.

Had always more satisfaction in doing ( for example ) off and on hire surveys. At least these were tangible , what you saw was what you got and
few could argue with you.

JC

Hague
15th April 2007, 17:00
John/Dave,
Not exactly draft Surveys but close enough.
Sailed for a company in the early 70s who had their Cape Size Ore Carriers on T/C to Bisco.
One vessel, on her maiden voyage in 71, loaded Dampier for Port Talbot. During loading the German Master & British Mate went ashore and during the loading the British 3/0ff formed a drinking relationship with a 'fellow scouser' in the ship loader. 'Coldies' were relayed by heaving line. No 9 hold was filled to such an extent that ship and shore labour had to 'level' the cone to enable the the hatch to be closed. The balance of the cargo had to go into No.1 to relieve the 'trim' said to be inxs of 20 feet. Midship TSTks and DBTks were filled to alleviate the 'hog' 17" on sailing. Due to the Master & Mate keeping quiet as they would not have come out well as they were both ashore the 3/O was promoted to 2/O on arrival in Europe and flew out to Japan for the maiden voyage of the 'sister'. which again loaded Dampier for Rotterdam. Unfortunately the demon drink appeared again and that ship was lost on her maiden voyage at 03:45 hrs on 26/12/72 off Guernsey.
In 77, I was Master of the first ship and knowing the history of the overloading used to do a daily inspection for cracks and would never permit alternate hold loading which as you both no will give a 'hogging moment'.

lakercapt
15th April 2007, 18:54
Aways thought that draft surveys were a crock.
Getting an accurate draft when there was a chop n the water was next to impossible. Then to compound it this mean of mean means was taken to two decimal points!
One occassion a very officious little fellow from Japan wanted to add tonnage for water ballst supposedly in a tank. Had the crew open the tanks and he went inside to check them out. One had a puddle and he wanted to measure it and calculate how heavy it was!!!.
K was a guess at best.
There were many ways to defeat the whole exercise as John noted. There were more but I will take them to the grave (or with sufficient inducement will tell)
Bill

John Cassels
16th April 2007, 08:16
Glad to see this thread come alive again.

Hague , a similar incident happened on one of the Denholm cape size bulkers,
I think it was the Gallic Bridge which overloaded in Pepel (upcreek from
Freetown). It was quite some years ago and will have to look through the
old copies of Denholm news te refresh the memory. Seem to remember that
the excuse was that the mate on deck was so preoccupied with trying to get
ballast out that he forgot to stop the run when he should have. It had dire
consequences as she could not even sail due to draft restrictions in the river.
Will try to find out the rest of the story.

Bill; glad to get yr input re the famous draft surveys. Yes it was always
amazing how some surveyors would calculate a load of zinc concentrates
to the nearest 10 kilos when the didn't even know how much ( for example )
paint was onboard. I guess the only reasonably accurate way was to do a
before and after survey ( outurn survey) where the only thing that changed
was the consumables. It didn't then really matter what the K or ballast was.
But how many surveyors insisted on this ..........very few.
Won't press you for your secrets Bill , though would be interesting to hear
them or did you sign the MSA ( Misener Secrets Act ).

JC

Pilot mac
16th April 2007, 13:31
A similar incident springs to mind. Loading Sulphur in Vancouver and all going smoothly. There was a brewery strike and shore side labour desparate for a drop of the amber nectar. Of course our Jolly Jack's came swiftly to the rescue, supplying half the waterfront with Swan lager and anything else they could sell. The result was a peak of sulphur out of number four which made the pyramids look small. The operator was asleep and just kept pouring! Luckily we were geared and were able to move the stuff around so as to close the hatch cover. Happy days??!

regards
Dave

Hague
17th April 2007, 21:54
The following article was published in the Nautical Institute monthly magazine (Seaways equivalent) 1975 and caused great me embarrassment as I was the only British officer (C/Off) on the vessel. The German Master was relentless in his ridicule. Whilst my memory cannot quote verbatim I will be too far away.

The writer (now a Fellow of the NI) and at the time C/Off of a Panamax BC was concerned that on arrival at Ijmuiden the vessel was always 'by the head' having loaded at Narvik or Kirkenes to arrive at the destination even keel.
The following caused were considered in an academic style:
1. Were the 'cones' of Ore in the holds vibrating there way forward in the holds, because the Burtons and Nories on the Chart Room Book case were doing so. This was discounted threw the intervention of the differential calculus. Hmmmmm!
2. Were the several inches of 'strippings' left in the DBTks which moved forward whilst underway and hence the cause. This too was discounted (I am not sure what the Charterers thought if they bothered to read as that declaration would have earned you instant dismissal in the company I was in)
3. Was the vessel trying to align itself in the earths magnetic field. This too was discounted (thoughts of a 70k tonne compass needle ...gave a new meaning to 'splitting B'.
4. The relative positions of B and G was touched on and dismissed (unfortunate, as he would have been close)

The following month's issue a German Master suggested that the writer should consult Derrets Ship Stability and in particular that section on EFFECT OF CHANGE OF DENSITY ON DRAFT ( Sec 37 page 289) 1972 Edition.

For the rest of the voyage comparisons were made between the requirements for the German A6 against the British Master (FG).

Pilot mac
18th April 2007, 14:28
Very strange co-incidence Hague, I was Mate of a 40,000 tonner with a Mates ticket . It bothered me to discover we were arriving by the head after an ocean passage when I had calculated even keel. Change of trim with change of density was not in the Mates syllabus at the time so how was I to know? I remained bothered untill doing Masters where of course it was in the syllabus and all became clear.

regards
Dave

Hague
18th April 2007, 17:39
Very strange co-incidence Hague, I was Mate of a 40,000 tonner with a Mates ticket . It bothered me to discover we were arriving by the head after an ocean passage when I had calculated even keel. Change of trim with change of density was not in the Mates syllabus at the time so how was I to know? I remained bothered untill doing Masters where of course it was in the syllabus and all became clear.

regards
Dave

Dave,
The author of the article mentioned possessed an Extra Master's at the time of writing and should have known better. Maybe that is another thread as I always thought Extra's was over rated and well within the ability of any of us who passed Master's (pre 78).

lakercapt
18th April 2007, 23:02
Although not about draft surveys its about vessel drafts.
In the Great Lakes when warmer weather comes (in about a months time hopefully) we have an unusual happening.
The boats are always loaded to maximum draft to transit the Welland canal or seaway.
Not a fracton of an inch over the allowed draft is permitted otherwise you are halted until its retified (a major problem).
When the weather is warm and because the water is cold there is considerable hog experianced.
Because of this we use sprinkler systems on the ship. Before arriving at lock #8 or St.Lambert locks the sprinklers are turned on to cool the decks and minimize the hogging effects.
Many a question I have been asked about why we have the decks and hatches wetted and that is the reason.
It works too!
Bill

Hague
19th April 2007, 09:11
Although not about draft surveys its about vessel drafts.
In the Great Lakes when warmer weather comes (in about a months time hopefully) we have an unusual happening.
The boats are always loaded to maximum draft to transit the Welland canal or seaway.
Not a fracton of an inch over the allowed draft is permitted otherwise you are halted until its retified (a major problem).
When the weather is warm and because the water is cold there is considerable hog experianced.
Because of this we use sprinkler systems on the ship. Before arriving at lock #8 or St.Lambert locks the sprinklers are turned on to cool the decks and minimize the hogging effects.
Many a question I have been asked about why we have the decks and hatches wetted and that is the reason.
It works too!
Bill

Thanks for that Bill.

John Cassels
20th April 2007, 09:02
Heard a story once , that in the 1930's , ships constructed for the coal trade
had a hog built into them. Always thought it far fetched but could have an
element of truth.
Bill , it was only midship area decks that werer wetted , I take it ?.

JC

john shaw
20th April 2007, 14:59
Heard a story once , that in the 1930's , ships constructed for the coal trade
had a hog built into them. Always thought it far fetched but could have an
element of truth.
Bill , it was only midship area decks that werer wetted , I take it ?.

JC

in the 1910s,up to the late 30s, the Ayre-Ballard "Arch Deck" steamer was very popular with collier owners because the large hatches and pillar free holds made them self-trimming -- this design had a longitudinal curvature of the hull which made them appear hogged. Perhaps that was the origin of the story?

lakercapt
20th April 2007, 15:08
Heard a story once , that in the 1930's , ships constructed for the coal trade
had a hog built into them. Always thought it far fetched but could have an
element of truth.
Bill , it was only midship area decks that werer wetted , I take it ?.

JC

Hi John
No the whole deck area was covered by the sprinklers.
Exception was the forecastle and pilothouse.
The decks got really hot so you could not stand on them with your baries.
Bill

Hague
20th April 2007, 21:59
Bill,
Last time I was in Port Cartier around 74 they had a bubbler system to deter icing within the dock. Did they have this system elsewhere in Canada.
Brgds

Hague
20th April 2007, 22:05
During the 70s there were three large self discharger's around named the :
Phosphor Conveyor.....Hendy Int'l
Marcona Conveyor......Marcona Transport
Universe Conveyor......Daniel K. Ludwig

Any memories.............I have!

lakercapt
20th April 2007, 23:58
Bill,
Last time I was in Port Cartier around 74 they had a bubbler system to deter icing within the dock. Did they have this system elsewhere in Canada.
Brgds

Was never really efficient and as normal the shipping season ends when the canals and rivers freeze up.
This last winter there were a few trips carried out until late winter as December and January were unseaonably mild (we made up for it in February and March.) Not Global warming !!!!
On the "lakes" the major part of the cargos are carried by self unloaders. The traditional "lakeboat" the straight decker is now on a decline and many some are being converted. There will be no more built as evcen traditional cargo such as grain is going in self unloaders.
Bill

Hague
22nd April 2007, 10:04
Was never really efficient and as normal the shipping season ends when the canals and rivers freeze up.
This last winter there were a few trips carried out until late winter as December and January were unseaonably mild (we made up for it in February and March.) Not Global warming !!!!
On the "lakes" the major part of the cargos are carried by self unloaders. The traditional "lakeboat" the straight decker is now on a decline and many some are being converted. There will be no more built as evcen traditional cargo such as grain is going in self unloaders.
Bill

Bill,
I have always thought of self dischargers as a nightmare. Memories of conveyor belts in the 'duct keel' and conveyor passing between twin 'Pielsticks' (because of low profile) in engine room. Even the more recent smaller variety (12k) on the Norwegian coast are not much better.

lakercapt
22nd April 2007, 16:48
Hague
Self unloaders are a special breed unto themselves and the modern ones are very efficient.
We could unload about 25,000 tonnes of iron pellets in four hours.
A busy life as you were always on the go. More so if you had more than one berth to discharge.
The best self unloader I was on was "Algosoo" one of the last lakers with the pilothouse ford.
The unloading gear was aft and you always had a peaceful discharge. She had three tunnel belts and one loop belt. They had specially designed tunnels and four "Tunnelmen" operated the hopper gates. The electrician was in charge of the system taking instructions from the mate on watch about which gates to open to keep trim. One mate was always at the boom controls at all times.He also was in charge of ballasting.
One season I did 126 trips and many of those were multi berth discharges. Got to be a dab hand at manouvering the boat. Even backing miles as there was not enough room to turn in many rivers and creeks.
It takes its toll and you are more than ready when vacation times roll round.
Bill
.

Hague
22nd April 2007, 22:31
Hague
Self unloaders are a special breed unto themselves and the modern ones are very efficient.
We could unload about 25,000 tonnes of iron pellets in four hours.
A busy life as you were always on the go. More so if you had more than one berth to discharge.
The best self unloader I was on was "Algosoo" one of the last lakers with the pilothouse ford.
The unloading gear was aft and you always had a peaceful discharge. She had three tunnel belts and one loop belt. They had specially designed tunnels and four "Tunnelmen" operated the hopper gates. The electrician was in charge of the system taking instructions from the mate on watch about which gates to open to keep trim. One mate was always at the boom controls at all times.He also was in charge of ballasting.
One season I did 126 trips and many of those were multi berth discharges. Got to be a dab hand at manouvering the boat. Even backing miles as there was not enough room to turn in many rivers and creeks.
It takes its toll and you are more than ready when vacation times roll round.
Bill
.

Mentioned several self discharger's in an earlier thread yesterday. Only one, the Marcona Conveyor had twin tunnel belts.

Hague
2nd May 2007, 19:08
Heard a story once , that in the 1930's , ships constructed for the coal trade
had a hog built into them. Always thought it far fetched but could have an
element of truth.
Bill , it was only midship area decks that werer wetted , I take it ?.

JC

John,
Supervised the repair of bottom damage (84 m/t) incurred by grounding at a well known yard in Hamburg in the early 90s. The repair was extensive and had the effect 'drawing' (heat) forward and aft together ( like a bottle screw). The Hog was clear for all to see and the yards explanation. That is good! Now you can load more cargo!.... True.

The Captain
14th September 2007, 05:42
Judging by some of the comments made in another thread (Pilot Error) I gather some members don't have a very high opinion of "Draft Surveyors".

As a retired surveyor of 18 years standing I feel I should try to defend our reputation. I would be the first to admit there are some that I have noted that are not the best!! The majority will try their best to achieve the best result for the vessel and offer sound advice to Masters and Chief Officers on loading bulk carriers and basically that is all they can do as the final responsibility for safe loading is down to the Master of the vessel. I and probably every other surveyor has come accross many Officers that really don't have a clue when it comes to the final stages of loading a bulk carrier. Nowadays many ships are quite prepared just to leave it to the surveyor and if they can't achieve they quantity of cargo requested blame it on the poor surveyor as being incompitent. 90% of the problems stem from not understanding the changing conditions the vessels undergo while loading and because the "loading computer" says they can do something it must be right. Computers only evaluate the data that has been input in to them, they dont think, thats for humans - rubbish in rubbish out.

The system of draft surveys is as fair and correct as possible given the ships data (Hydrostatic Tables). The "quarter mean" draft is most accurate way of ascertaining the displacement of a vessel regardless of which way it is calculated and should be take to at least 5 decimal places (ie 16.56785 metres). Like "shiphandling" draft surveying is an art which is mainly learned by experience not by reading about it in a book or at college, although that can help in either case.

I have not seen any comments in other threads from surveyors, may I am the only one on S/N but would welcome any comments from members with regard to good, bad or indifferent surveys/surveyors, may be I can help to clarify a point, remove some of the "mystique" or just make the surveyors reputation a little better than it appears to be - someone who steals the rightful cargo freight from the ship. Remember most bulk cargo draft surveys are paid on the tonnage they certify as being onboard - the more they load the more they are paid so it is their interest to load the ship properly.

I await the many comments from my fellow members with interest, to find more about where I was for those 18 years check my bio.

No death threats please(==D).

Cheers John

Gulpers
14th September 2007, 06:12
John,

There is an existing thread on Draft Surveys here (http://www.shipsnostalgia.com/showthread.php?t=10839&highlight=draft+survey) which you may like to contribute to.
It will give you the chance to defend your "art!" (Thumb)

John Cassels
14th September 2007, 08:02
As Ray has suggested , you should read the previous thread regarding draft
surveys , I will reserve my comments until then , including your ridiculous
supposition that displacement should be ascertained to 5 decimal places .

David Byrne
14th September 2007, 08:13
I would support the general thrust of what 'Captain' has said about draft surveys and surveyors except the contention that the draft should be read or computed to 100 microns accuracy!!!!!

David Byrne

Bill Davies
14th September 2007, 08:37
The Captain,
I would do as John Cassels recommends and read the previous thread on this topic where the subject was well examined. Been involved in loading, discharging bulk carriers of all sizes since 62 and witnessed many devices used to assist including the excellent tool used in Port Talbot by Pete McCallister and mentioned in the recommended thread. However,5 decimal places? are you serious?

The Captain
14th September 2007, 11:33
I have previously read the mentioned thread and found no comments from surveyors. With regard to comments about the use of decimal places I assumed that I was addressing people who had an appreciation of draft surveys. I will explain if a vessel has the following drafts:-
All to 2 decimal places and corrected to the perpendiculars.
Fwd Port 16.00 Fwd Stbd 16.01
M/ship P 16.21 M/ship S 16.27
Aft Port 16.15 Aft Stbd 16.19

The fwd mean = 16.005
aft mean = 16.17

F&A Mean = 16.0875

Mid/ship mean = 16.24

M/M = 16.16375

M/M 2 = 16.201875 (if you rounded every calculation off to 2 places the M/M2 would be 16.21)

As can be seen from the above the M/M2 has 6 decimal places, which is what I used in practice, just by reading the draft to centimetres.
Given that some ships have a TPC well in excess of 100 tonnes it would seem to me expedient to be as accurate as possible with the calculation so yes Bill I was serious. However I will admit that the vast majority of my clients didn't want tonnage with decimal place, just straight tonnes and or Long Tons.
Since I was advised to read previous threads I suggest those who thought excessive use of decimal places a little over the top please re-read my original, I was talking about a draft to enter the hydrogrphic tables with.

I remember being asked quite seriously by one Master to load his vessel to her summer marks, which had 4 decimal places as per the ships papers, that I couldn't do, the centimeter below only.

I take it that John and David don't like surveyors very much from their comments although David and Bill seemed to get very well with Pete McCallister at Port Talbot which is good. I am sorry you feel the way you do as I have always tried to be as fair and as accurate as I could possibly be in my eighteen plus years as a draft surveyor.

Best Wishes, John

Bill Davies
14th September 2007, 12:23
John,
Well responded to. However, not wishing to be pedantic if you applied the appropriate standards to decimal hierarchy you would be left with 16.20.
You would have arrived at the 16.21 if you were a little more rough and ready. But more interesting to the likes of myself and possibly JC, did you have any devices similar to the one described in previous thread and used by Pete McAllister (Spelling?). Also, as this is nostalgia, any tricks, dodges you picked up over the years. I am sure we could generate an interesting dialogue/thread.

John Cassels
14th September 2007, 14:10
One does not need to be a surveyor to have an appreciation of draft surveys.
As ch.mate ; port capt and marine supt. have done many of them plus
appointed plenty of surveyors for joint surveys.

If I hired a surveyor who said he could calculate outurn to the nearest 10 MT
I was happy . If he said he could calculate to the nearest 500 gramme , I
would have thrown him out the office.

I have nothing against draft surveyors , but as noted in the previous thread,
the hype associated with draft surveys is way out of line. In anything but the
most perfect weather conditions , the outcome is , at best , a possible
approximation.

OK , assuming you have 1/4 M of M worked out to 5 decimal places and you
have your displacement to the same degree of accuracy , how do you get
the constant to this same degree , do you have everything and everybody
weighed. Do you sound all consumable tanks yourself , do you go into
every tank and check for sludge , mud , or any of the many ways to upset
a survey.

This will do for a start.

Bill Davies
14th September 2007, 15:05
Deadweight Constant could be a thread on its own and is one of the least understood elements in Draft Surveys. The visual approximation etal supports JC above. Try reading a draft at Sepitiba Bay. You need to be very patient.

The Captain
15th September 2007, 02:12
John like most "hype" it has come to pass from expediency. When I was first at sea we and loaded cargo in bulk the draft survey was usually carried out by the Mate and/or Master. During my time on general cargo ships my experience with cargo surveyors was mainly restricted to cleanliness and quantity surveys of oil in deep tanks with occassional draft survey, I can remember about four in 11 years that were carried out by surveyors. It wasn't until I sailed on the Australian coast (1976) carrying bauxite around that draft surveys became a "norm" for me. With a draft survey for loading and for discharge four days later there was plenty of exposure to draft surveys and surveyors. During those time the surveyor came aboard for the intial survey and didnot return until the vessel completed loading and if in the early hours then during daylight if possible. The surveyor certified the cargo quantity only and did not assist in the loading, that was the job of the Mate under the Master. As far as I am aware this practice is still carried out in that trade. It wasn't until I started surveying myself that it became apparent that ability of the "normal" Mate on a ship wasn't able to carry out a draft check and order a final quantity of cargo in a reasonable time, say 30 minutes. The shippers and terminals employed surveyors to assist the ship so as to limit the down time for draft checks and also to liasse between the ship and the terminal. This proved very effective over the years to reduce down time and allow ships to sail on time. Gradually it was noticed that more and more ships were actually relying on the surveyors to do the final draft check and cargo allocation for them. I was taught a method of draft reading for open port terminal when I started surveying in 1987 and have used that system for the whole of my time, I have found it to consistent and reliable regardless of weather conditions. I realize that there are some people out there who will say "Rubbish, nobody can read a draft accurately in a one metre swell, impossible" - I can and I know of about ten others that can.
It basically comes down to the fact that most Masters nowadays have virtually no experience of close water ship handling except for anchoring, hence the total reliance on pilots and the same goes for draft surveys where time is vast ammounts of money. While I have no experience of "box boats" does the Mate/Master have any say in what box goes where, I doubt it but could be wrong, cargo planners are employed by terminals to plan the loading of the ship before she even arrives, what input does the ship have? I am sorry to say this but gradually the skills of the mariner are being wittled away to situation where there is very little under the direct command of the Master (computer communications, direct intervention from ashore by computer, instructions for the Master to contact head office if things don't go quite right with the loading before any decision is made, usually not by the Master but by the office. No my fellow mariners soon the only thing left to the Master will be the "can" that he has carried since the trade began, nobody will want that responibility because the only time there is any mention of it is when things go wrong and then it becomes the "Masters Responsibility".

Enough of this argument, I was trying to see if there were any surveyors out there in S/N land but it seems not, maybe they are too busy.

Best Regards John

John Cassels
15th September 2007, 07:58
John , this is not an argument but a discussion that you started which I find
very interesting. Your last post does not say very much and you still have
not answered the question of how you calculate the constant to the same
degree of accuracy as you say you can calculate the displacement to.

As I said before, you don't need to be a surveyor to appreciate the question
so please explain to us.

Bill Davies
15th September 2007, 08:44
John (The Captain),

I was reading your post with interest and towards the latter part with agreement until you destroy the post with your penultimate paragraph where you seem to think that only those who describe themselves as surveyors can have an opinion. I find that offensive after fifty years at sea.
So I will do as you suggest and leave it there which is hardly to route to constuctive dialogue on a thread of particular interest to me and JC I think.

Brgds
Bill

John Cassels
16th September 2007, 08:08
John (The Captain),

I was reading your post with interest and towards the latter part with agreement until you destroy the post with your penultimate paragraph where you seem to think that only those who describe themselves as surveyors can have an opinion. I find that offensive after fifty years at sea.
So I will do as you suggest and leave it there which is hardly to route to constuctive dialogue on a thread of particular interest to me and JC I think.

Brgds
Bill

Well said Bill. As I indicated a couple of times , one does not need to be a
surveyor to be able to perform or have knowlege of draft surveys.

The famous constant ; No reaction as yest , but I think we both know what
the answer would be !!.

The Captain
17th September 2007, 06:29
John, I think it should be the imfamous "Constant". Since you asked about calculating the displacement so accurately I will try to answer.
The corrected displacement is that displacement allowing for trim and dock water density and is reliant on the accuracy of the hydrostatic tables. The corrections for trim are usually calculated by the surveyor using the accepted formula for that purpose, the density correction likewise. Most surveyors calculate the displacement to the nearest tonne as found by the use of the Hydrostatic tables, the same as any ships officer would do. Some hydro tables have a trim correction table included in them but most surveyors find these to by unreliable in their consistence and so prefer to use the formula instead.
With regard to the ballast quantity, the tanks should be sounded either by the surveyor or with the surveyor present and on some occassions with an officer also in attendence to act as a witness on behalf of the vessel. This can avoid any disagreement with the found ballast. The density of the ballast water should be checked (by the surveyor as part of his job, using his standard "Draft Survey Hydrometer) in several tanks. Because the normal loading period is usually less than 48 hours the ships fuel figures are normally accepted as given, the same applies to lube oil, if not included in the "constant". Freshwater is also accepted if a gauge glass is used. The reason for accepting ships figures is that these quantities are not likely to change drastically over the loading period unless, of course bunkers are being loaded or the F/W is topped up. The fresh water can be checked quite easily by the surveyor where topping up has occured and producing a bunker receipt can verify the quantity of bunkers loaded. As you are very much aware the "contant" is not constant, it varies and really should not be called a "constant" but unknown weights.

The final survey is carried out using the "constant" found at the initial survey and an allowance made for the fuel used during the loading period provided by the ship (usually between 5 and 20 tonnes per day). The ballast ROB figure is calculated using soundings found in a similar way to the initial survey. The surveyors I have come into contact with have been quite fastidious about ballast as this is an uncheckable quantity when the loading has finished and the ship has sailed.

The cargo quantity cerified by the surveyor has usually to be in tonnes only but occasionally the shipper requires one or two decimal points, this can be a problem and I agree that it can be very difficult for two or more people to agree with each other when such a degree of accuracy is called for. I can assure you I would not be so pedantic as to argue over decimal points of a tonne, I really wouldn't argue with ship over 10 or 20 tonnes on a large vessel but unless someone could show me an error in my calculation I would not change my findings.

Before anybody starts on with densities and hydrometers, I am not prepared to go there under any circumstances, I've got myself into enough trouble as it is.

As for the comments from Bill, I wasn't trying to be insulting just stating a fact of life as I have experienced it over the past few years. I believe that the loading of cargo nowadays is controlled by shore people some of whom would know a ship if they fell over it and I find that very disconcerting, be they planners, terminal operators or office workers in chartering departments, I apologise to any of the above in advance as it is just the way things seem at the ships side. The Master/Ch. Officer seem to have all the responsibility and very little input, unlike when I went to sea where the cargo planning was done onboard.

I and the surveyors I worked with took our job and responsibility very seriously and tried our best to be as accurate and honest as possible in our dealings with ships staff. I must just put this last comment in, I received more "Thankyou, Mr. Surveyor" than adverse comments from ships and also had many "Nice to see you again" comments if I met up with them again.

On re-reading my earlier comments may be I did sound "petulent", for this I am sorry it wasn't totally intended.

Shall we say truce on the "accuracy" of draft surveys, although I would be willing to try and answer any queeries members may have without getting into a heated "discussion"

Many thanks
John

John Cassels
17th September 2007, 08:35
Thanks your reply John. Clear and concise and very interesting.

I think that what got me wondering initially was your calculating draft to 5
decimal places. Most ships I have done surveys on have displacements
given every 5 cm. Therefore even at 3 decimal places , you're into interpolation. also the high degree of accuracy you strive for is only as good
as the accuracy of the deductables.
Among my draft survey experience was working as port capt for a shipping
company which had the contract for carrying high grade zinc concentrates -
about 30.000 mt per month. The reciever always used the same surveyor
( a spitting image of Hercule Poirot in the films), I acted together with the mate for the carrier. Many a time the survey was carried out at night ,
blowing hard , raining and cold. He would read his drafts to the nearest cm.,
was so fat that he could not get over the side to read the outboard midships
draft , so his accuracy was gone even before he started. Checking the rest of
the deductables was a laugh. Sounding ballast tanks , he would shelter
behind a coaming or something and note down what was shouted to him.
There could have been 10 cm in every tank and he would never have known. Never checked if the bucket was clean before getting a dock water sample.
After all this , he would come up with an answer to the nearest tonne !!!.
Although this was ridiculous , we never questioned him as his figure was
always a good deal more than the blading weight.

I guess what I have been saying all along is that a draft survey is only
accurate if ALL parts of the survey is accurate and in my experience this is
seldom the case. And what about all the little tricks of the trade ?. Ballast main full at initial survey and empty at final survey , bottom 5 cm of a
sounding pipe cropped off and an extra striker plate fitted ?.

You undoubtably have more experience with draft surveys than I do and it
would be interesting to hear of them . Definitly an interesting subject.

Bill Davies
17th September 2007, 10:26
John (The Captain)

Good response. And well answered by JC who has covered what would have been my response. Have either of you two gentlemen ever used devices similar to that described by Hague as being used in Port Talbot.

Bill

John Cassels
17th September 2007, 18:51
Bill, I knew Peter MacAllister and even sailed with his brother Willie as Master
but have never seen his device. Have read Hague's original post but still do
not really understand. I see the principal but wouldn't the device have to
be placed against a datum , for example , a known mark on the device at (say) the 45' draft mark. How can it just be thown at the draft marks and the
upper and lower oscillations measured , measured against what ?.

Bill Davies
17th September 2007, 21:36
Bill, I knew Peter MacAllister and even sailed with his brother Willie as Master
but have never seen his device. Have read Hague's original post but still do
not really understand. I see the principal but wouldn't the device have to
be placed against a datum , for example , a known mark on the device at (say) the 45' draft mark. How can it just be thown at the draft marks and the
upper and lower oscillations measured , measured against what ?.

John,
I have not seen the device myself but had heard about it many years ago. Apparently, the two clear plastic tubes(open at top and bottom) are connected by a reducer i.e the upper being about 3" x 48" and the lower 1.5" x 48". Connected to the very top of the larger tube is a powerful magnet (old magnetron) secured by a grip of sorts. The device is fitted with a old heaving line secured iwo magnet. When approaching the draft mark the tube is lowered beneath the waterline by the heaving line and fills. When ready to read the draft the device is lifted out of the water about a foot or so and the magnet placed or thrown the foot or so above the approximate draft mark. What you have now is the larger bore clear plastic tube supported by the magnetron lying vertical disposed alongside the mark under inspection and the waterlevel oscillating within. Sounds good. Wish I had one prior to 72 which is when I was last time over the side or in a small boat reading a draft.

lakercapt
17th September 2007, 22:36
I believe that the purpose of the device is to be able to read the draft accurately when there is a chop on the water. As the water is well below the surface it takes the water there alleviating the surge/chop and hence giving a more accurate reading as the water that far down is not effected.
(Still consider it white mans JUJU) and even taking it to a hundred decimal points is just another add on to make it look as if its a science. Best guess at most. Course that is my perception.
Bill

Bill Davies
17th September 2007, 23:04
I believe that the purpose of the device is to be able to read the draft accurately when there is a chop on the water. As the water is well below the surface it takes the water there alleviating the surge/chop and hence giving a more accurate reading as the water that far down is not effected.
(Still consider it white mans JUJU) and even taking it to a hundred decimal points is just another add on to make it look as if its a science. Best guess at most. Course that is my perception.
Bill

Exactly

John Cassels
18th September 2007, 08:13
Still don't get it. The device must be scaled against something . If reading
the draft to 1/2" , then the device must be placed to within 1/2" of a known
draft. How did they do that , can't just be with a heaving line ???????????.

Bill Davies
18th September 2007, 09:05
Still don't get it. The device must be scaled against something . If reading
the draft to 1/2" , then the device must be placed to within 1/2" of a known
draft. How did they do that , can't just be with a heaving line ???????????.

John,

I'm going to try and draw a picture as I have probably not described it very well. I am sure that if my drawing is incorrect there will be some out there who will correct.

Brgds

Bill

rajabhat
9th July 2009, 08:56
i am looking for a marine surveyor job. i have got more than 20 years experience in this field.

regards

Bill Davies
9th July 2009, 09:02
Please clarify!
Do you have 20 years ALREADY in this field OR, do you have 20 years in the shipping industry - at sea etc?

sidsal
10th July 2009, 11:21
I find this thread most interesting. Having left the sea in 1952 before these monster ships appeared, the question of hogging and sagging did not, I believe, have the signifigance which the big ships have.
Mention is made in one Thread of some ships being built with a hog in them. The WW1 equivalent of the WW2 Liberty ships were known as "Hog-Island ships". Their fore and aft end had a definite drop from amidships. I heard that they were built with the idea that the engines amidships would straighten them - which it didn't. I had a narrow escape once when I was urged by the union chap in L'pool to join one which was going to the China coast.
In 1952 I was 2nd Mate of the Esso Stockholm - one of the largest tankers in the world then - 36,000 tons - ha, ha !!! On a passage Ras Tanura to Montreal we had a severe storm when approaching the Grand Banks and it was disconcerting to see the loose bolt in the spot where the catwalk joined the midships accommodation block, move about 9" back and fore as she bent in the seas. The loading method meant , if I recall that the midship tank was virtually empty. It's a long time ago so my memory might be failing.
I do recall however going onto the monkey island to take a photo of her plunging into the trough and a big wave knocking me off my feet. On looking down the bridge wing at a height of 70 feet was full of water.
Happy days.

chadburn
10th July 2009, 12:12
A good paper to read on hogging and sagging is called "Effect of variations in loading on Longitudinal structural stresses in ships" written by W. Thomson, It deals with the both the overall problem on oil and dry cargo and the differences between Machinery Amidships and Machinery Aft vessel's

John Cassels
10th July 2009, 18:34
Good news , one of the most interesting threads opened up again.

lakercapt
10th July 2009, 21:56
Still don't get it. The device must be scaled against something . If reading
the draft to 1/2" , then the device must be placed to within 1/2" of a known
draft. How did they do that , can't just be with a heaving line ???????????.

John
The usual procedure was to use it alongside the plimsolls mark and use that as the reference point
Bill

Bill Davies
10th July 2009, 22:30
John,
The device was placed alongside each of the draft marks with the exception of the inboard amidships which did not require it.
Brgds
Bill

Geoff_E
10th July 2009, 22:50
Please clarify!
Do you have 20 years ALREADY in this field OR, do you have 20 years in the shipping industry - at sea etc?

You've answered that one yourself Bill!

Bill Davies
10th July 2009, 22:59
Not really. The post is ambiguous and I read it that he is a mate with 20 years experience and looking to get into Draft Survey work.

John Cassels
11th July 2009, 07:57
Derek , that's the whole point in many parts of this thread.

Sod's law has it that draft surveys are taken when there is a good swell
or sea running and it is nearly impossible to take an accurate draft reading
no matter how many times you read a high and low and take a mean.

You then have surveyors who take this read draft and proceed to calculate
a displacment to three decimal fugures and present the result as gospel !!.

Supergoods
11th July 2009, 12:30
Mention is made in one Thread of some ships being built with a hog in them. The WW1 equivalent of the WW2 Liberty ships were known as "Hog-Island ships".

The term "Hog Island" actually refers to the area known as Hog Island on the Delaware south of Philadelphia where an emergency shipyard was established in WWI
This is where the Philadelphia airport is now located.

joebuckham
11th July 2009, 14:01
Not really. The post is ambiguous and I read it that he is a mate with 20 years experience and looking to get into Draft Survey work.

bill, i read that rajabhat has 20 years experience in marine surveying, no ambiguity (Thumb)
b rgds

Satanic Mechanic
11th July 2009, 14:22
I know this device, it is still in use in Korean ship yards when you are doing tonnage tests. Its very good and while the reading is still an average it is a very very good average. I actually thought it was an idea the yards had come up with, very interesting to hear that it is an old invention. possibly a bit of overkill for run of the mill surveys but hey it works so what the hell.

Bill Davies
11th July 2009, 14:37
Would agree. And like most things which are useful,very simple and well within the remit of any engineer to fabricate!

artysan
11th July 2009, 16:14
in the late 1980's there was a young college trained draft surveyor working the Dutch ports Amsterdam and Ijmuiden who used a device for taking the midship draft in adverse conditions i.e swell etc. Such device was designed and made by his father, a retired ships Master in his garden shed and was available to order for $US 100. I was that impressed with the accuracy of the device I purchased one and used it for many years loading a 22000 tonne collier on average once a week until retiring in 1997 so it proved very robust.
As far as memory serves it consisted of a 1 m steel tube about 1 inch ID with 2 m plastic hose of similiar ID attached to lower end. The top six inches or so of the steel tube unscrewed and held a float switch and batteries and a buzzer then on top of tube in a perspex dome a light much on the lines of a lifebuoy light, air holes were provided to release any trapped air in tube as water rose also a loop to attach a standard 20 m Rabone tape or as an added extra a similiar tape with a wire core to better take the weight and reduce tape stretch Method of use was to first establish distance from deck edge or even bulwark if you did not want to bend down iwo plimsoll to summer load line and use this as a constant. then lower device into water when light glowed steady and buzzer sounded continuously take reading at deck edge or bulwark and apply constant hey presto Draft amidships if necessary correction could be applied for loading to winter marks and/or density. Purpose of buzzer was for daytime use when light might be difficult to see. As I said used this for many years and outturn figures always in reason. Worked well in quite laarge swell say 4-6 feet and winds upto force 5-6 above that tape tended to blow around and back to guesswork

Another little device I found handy when finishing off by oneself was a small spirit level if postions were found and marked on the hatch coamings when vessel upright, drydock usually best, where bubble was central with level in athwartships position then spout etc could be directed to keep it there when finishing off. Found this worked pretty well very rarely more than 2 cm diff in port and stbd midships drafts not bad in a vessel with 24.5 m beam save a lot of scooting around looking at drafts
Biggest danger is Bosun painting over your carefully made marks

Happy days pouring with rain blowing like hell and covered in coal dust

Bill Davies
12th July 2009, 10:42
Artysan,

You are raising two points here.

1. Take a look at the sketch in my gallery. I believe that the individual responsible for this was an ex Denholm Engineer, Peter McCallister, working as a draft Survey out of Port Talbot area. It worked well.

2. Keeping the vessel upright was best achieved, to my mind, using the water tube with fixed datum poles fixed to rails (P&S) above midship draft marks. Lights were OK but not good enough for final trimming.

Bill

artysan
12th July 2009, 20:02
Hi Bill
Had a look at your sketch and that device seems to be very much on the same principle although without the electronics. Strikes me that it would be more suitable for the more extreme weather conditions, being held in position by a magnatron although it appears that you still have to hang off a ladder overside to read it. this was one advantage of the electronic version Draft could be calculated from on deck

Never was lucky ??? enough to be on a ship fitted with loading lights so no experience there. However found the spirit level method quite useful as with upright positions marked at each hatch it could be used when directing loader when topping off. Not perfect i admit but enough to curb some of the excesses of some loader drivers

Back to amidships. Some of the smaller colliers (7000t) i was on still had the original collier boards these were made by the builders. In effect a 6 inch wide plank hung over the side at right angles to hull and clamped to the bulwark with the draft scale painted on them to match hull markings. Reading draft was then a matter of just glancing over the side. really only suitable for low freeboard vessels and inboard one had to be well fendered to avoid crushins against quay. These consigned to history now as to unwieldy to use on the larger colliers (22000t) in use today

Regards

Arthur

Bill Davies
12th July 2009, 22:03
Hi Bill
Had a look at your sketch and that device seems to be very much on the same principle although without the electronics. Strikes me that it would be more suitable for the more extreme weather conditions, being held in position by a magnatron although it appears that you still have to hang off a ladder overside to read it. this was one advantage of the electronic version Draft could be calculated from on deck


Arthur

Evening Arthur,

The device could only be set if one had a small mooring boat at ones disposal.
I never heard of anyone using it at the loadport due time restraints therein and I never heard of it being used by any other than the Port Talbot Surveyor.
I will however, vouch for its accuracy as, I am sure others will who have experience of it.

Brgds

Bill

lakercapt
13th July 2009, 03:44
Used trimming lights for 100's of cargo's where max lift was required and found out that they worked well.
Especially when the rate of loading was high.

Bill Davies
19th July 2009, 07:02
Especially when the rate of loading was high.

That being??

billxweki
29th October 2009, 17:44
Draught survey is an interesting and complex subject, it is, in my opinion, closer to an art than a science due to the number of variables involved. Like it or not, and I know many ship's officers do not, it is the method used for commercial settlement in many bulk cargo transactions and as such Independent draught surveyors play an important part in the business of shipping. Browsing the previous comments, it is obvious that there is some misconception of the requirements of a draught survey for commercial settlement. In all cases, so far as I am aware, a full commercial draught survey requires light and laden surveys to be carried out, this negates the use of "K" in the calculations, for if ever there was a misnomer then "constant" is it!
When boarding a vessel to carry out the initial draught survey, an experienced surveyor will be looking at many signs, for indications of the ship's officers capabilities and attitudes, the general condition of the vessel, the state of the the hydrostatic and ballast tables, where possible, records of previous draught surveys etc. etc.
When sounding ballast, it is normal to check sounding pipe heights, against plan if possible, but anyway to compare with final survey. Draught reading is done in conjunction with ship's officers and other third party surveyors and can be difficult in adverse conditions, however, various types of equipment are available to aid accurate reading and with sufficient experience it is possible to make a fair assessment of each draught. Given that maximum effort is made to obtain accurate readings for draught and ballast, it would seem foolish to me to allow rounding errors to creep into the calculations, consequently it is perfectly reasonable to work to four or five decimal places when obtaining MoM to enter the hydrostatic tables. In modern times, with the extensive use of laptops, it is no hardship either.
In my experience there are good and bad draught surveyors as there is good and bad in all walks of life, but the majority of independent draught surveyors I have worked with around the world have been conscientious, competent and honest. We do the best job we can, so don't be too hard on us.
Rgds Bill

JimC
29th October 2009, 18:15
Hi john - Peter was actually Willie's older brother. Quite a bit older.

I knew Willie quite well, great guy.

He died a few years ago, I don't know if Peter is still around or not.

Best Regards,
Roddie.

Hello Roddie!

I was going to say that! -stole my thunder so you did!

Willie and I were old pals . Last time I sailed with him was when he relieved me as 2/O on the Naess Sovereign. Last time I saw him was around 1968 when I visited him in the office.

Old Denholm hands will remember that the McAllister family were PDD ( 'Pure Dead Denholm').

Willies father was actually old Willie but was the spitting -image of the young version (or is that the other way round?)
I sailed with him when he was 2/E on the Ormsary. I think Peter was actually C/E on the EGTV Morar for a while and went ashore as Superintendent at Port Talbot in the late 60's. Willie's oldest brother was killed in London during the blitz. He was an Apprentice with the company and was working down the hold when a stray bomb went down to join him.
They also had a sister who worked in the office when it was at 120, St. Vincent Street in Glasgow.. Everyone swore the chimney on the family house at Bishoppbriggs was red with a black top and had a diamond D flag on it.

Happy days!

John Cassels
29th October 2009, 19:19
Hello Roddie!

I was going to say that! -stole my thunder so you did!

Willie and I were old pals . Last time I sailed with him was when he relieved me as 2/O on the Naess Sovereign. Last time I saw him was around 1968 when I visited him in the office.

Old Denholm hands will remember that the McAllister family were PDD ( 'Pure Dead Denholm').

Willies father was actually old Willie but was the spitting -image of the young version (or is that the other way round?)
I sailed with him when he was 2/E on the Ormsary. I think Peter was actually C/E on the EGTV Morar for a while and went ashore as Superintendent at Port Talbot in the late 60's. Willie's oldest brother was killed in London during the blitz. He was an Apprentice with the company and was working down the hold when a stray bomb went down to join him.
They also had a sister who worked in the office when it was at 120, St. Vincent Street in Glasgow.. Everyone swore the chimney on the family house at Bishoppbriggs was red with a black top and had a diamond D flag on it.

Happy days!

Agree with that Jim. Happy days indeed.

Sailed with Willie on his last rrip before going ashore. Naess Pioneer about
1968. Great Master and a gentleman.

John Cassels
29th October 2009, 19:27
Bill . Looks like you have had more draft survey experience that me.
That being said , as mentioned in previous posts . a good few of the
joint surveys I did were in Antwerp and nearly always at night and blowing
a gale.
The chop on the water was usually such that it was difficult enough to even
see the marks correctly let alone take a accurate reading. And then the
recievers surveyor would proceed to calculate out to 4 decimal figs.

You are of course correct in the assertion that commercial outurns are pretty
settled by surveys only I've yet to see one ( including my own) that I would
call really accurate.

billxweki
29th October 2009, 21:11
I wouldn't disagree, but accuracy is a relative term and the generally accepted tolerance for commercial draught survey is 0.5%, although i believe that overall a well conducted survey, in good sea conditions, is very much more accurate. In general the commercial outturn of a bulk cargo must be established by some means and the alternatives, such as truck weighbridge or belt weigher, are subject to inaccuracy as well and are very much more difficult to verify independently. I have to agree that calculating draught surveys out to the kilo is stretching the bounds of credibility, as I'm sure almost all independent draught surveyors would, however the requirements of letters of credit usually dictate at least 2 decimal places.
Bill