Hogging and sagging!

Mervyn Pritchard
4th March 2008, 21:52
A chap postd this video clip on another forum which i frequent. It is very dramatic and clearly demonstrates the distortion in a vessel's hull due to stress in heavy swells

http://www.youtube.com/watch?v=NE_ri8PkihE&feature=related

- Merv.

quietman
4th March 2008, 22:00
Will have to show my wife this she thinks Im joking when I tell her ships "bend"

Binnacle
4th March 2008, 22:00
Thanks for that Merv. Glad that's all behind me.

K urgess
4th March 2008, 22:36
I would've been VERY worried if I hadn't seen that sort of movement.

lakercapt
4th March 2008, 23:11
Had a lot of hogging ang sagging on lake boats as they are long and narrow compared to a convenional ship. Especially the one I sailed overseas. Also a problem in the spring on the "lakes" as we got hot days and the water temperature was cold. This caused the boat to hog and could cause it to become overdraft and not be allowed Seaway transit.
Used sprinklers on deck to keep it cool and its not an uncommon sight to see a dozen sprinklers all in action at the same time. Started before sunrise till dusk.

John Cassels
5th March 2008, 09:53
Nothing really strange here. This sort of movement ( inclusing the torsion
bending ) was pretty common in the '60's and '70's.

price
5th March 2008, 10:18
Lying straddled across the River Nene for a tide or more, resulted in Rowbothams 'Tillerman' being permanently sagged by about 2.5 inches. The explanation for the discrepancy on the deadweight summary was always sag.
Bruce.

benjidog
5th March 2008, 14:25
Very good demonstration for someone like me who has never seen it.

Brian

Jeff Taylor
7th March 2008, 21:52
It's hard to get used to the silence on a new welded ship after all the creaking on a riveted hull. Even with all the felt strips behind the paneling the old Queens used to make quite a racket in even a moderate sea.

Bill Davies
7th March 2008, 22:16
Nothing special here. Try a ULCC in ballast then you will see something.

Derek Roger
8th March 2008, 00:44
Are you not glad the shipyards have qualified welders and a Quality program .

Cheers Derek

PS Best place to see the Hog and Sag is on an oil tanker . Just stand at the aft end of the "Catwalk " and look forward . Ballast condition is best to see the large deflections .

captkenn
8th March 2008, 01:45
PS Best place to see the Hog and Sag is on an oil tanker . Just stand at the aft end of the "Catwalk " and look forward . Ballast condition is best to see the large deflections .

If you look at this picture here you will see two metal plates on the catwalk about a foot deep these are to allow the catwalk to bend in relation to the deck and the railings have a gap here too. It is surprising how little sea you need to see the movement.

surfaceblow
8th March 2008, 02:15
The Sealand Venture had tunnels on each side of the cago holds with the fuel oil piping and other services. The expansion bellows on the fuel oil line would crack and the openings would be big enough around to accomodate the cadet's finger.

The Cadet wouldn't understand why you do not put fingers in holes or cracks on a ship until I had a pencil in one of the cracks and had the cadet hold the dumb end of the tape and pencil while I measured the pipe line to be replaced. The pencil did not finish the measurement task and we were not in heavy seas no rolling or pitching.

R798780
8th March 2008, 08:21
The view from the bar (officers lounge) window on Oloibiri - a VLCC - was quite dramatic. The window faced forward and the focsle could be seen clearly rising and falling several feet relative to the manifold - the thwartships cargo pipes which were at half length.

K urgess
8th March 2008, 12:12
VLCCs going round the Cape were an interesting sight in the swell.
A sort of whiplash action between the bow rolling one way and the accomodation rolling the other.
Plus the bend in the hull moving aft from the bow just like the wave that caused it.
The early VLCCs were long and thin so it was very noticeable. ULCCs tended to be broader and squatter.

price
8th March 2008, 13:22
Anyone who has sailed on any of the Norwegian-type steam, Empire tankers, including the 'Esso Cheyenne' and the 'Esso Appalachee', ex 'Empire Coleridge' and 'Empire Dickens' respectively, will probably remember the extraordinary flexible movement of these vessels when underway in ballast conditions. The bouncy motions accompanied by rhythmic squeeking from deck joints and the flying bridge with every turn of the slow propeller, was felt most when standing aft. The view from the break of the poop past the centrecastle to the break of the Focsl'e was quite dramatic.
Bruce.

JoK
8th March 2008, 13:23
Alway fun to replace a pipe on deck after repairs. It either didn't fit being too long and you had to somehow get those flanges far enough apart to drop it in, or there was a huge gap between the flanges that you used long pieces of threaded stock to pull the flanges up enough to put the regular bolts in. The OBO I was on, we could never keep the fire main from cracking on the foscle. The bending and twisting would crack the pipe in the Tee.
In a sea, the bow would wave to you.

Bill Davies
9th March 2008, 20:17
I can remember a Cape Size Bulk Carrier which sailed Dampier in 72 for Port Talbot with an 18 inch recorded Hogg . Apparently, the 2/off (ex Brenda Silver) got friendly with the man in the ship loader and passed him 'coldies' on a heaving line. No.9 was loaded to such an extent that the cone of ore exceeded the hatchcoaming and had to be flatted with shore & ship labour. Ship sailed with Forepeak and midship DBTks /TSTks ballasted.
Understand from several who were on board at the time that 18" was conservative.
British Steel were very happy with that ship. Might be because she always had a good out-turn.

Orbitaman
9th March 2008, 20:29
It is reported that many a Chief Officer deliberately hogged a ship on its maiden voyage, as the hog stayed with the vessel to an extent for the rest of its life. Certainly, the two PSNC ships I sailed on had a similar permanent hog, allowing the vessel to load a little more than she would if the hog wasn't there.

gas_chief
12th March 2008, 11:08
I did one trip on a bulker as a 3rd mate. The mate there told me that the best way to get the max cargo, was to load as much as possible fore and aft and reserve the midships hatches for the last. This ended up hogging the vessel to the max before during the first few passes and then bringing her down midships; but thanks to the mean of mean of means of the midships draft being used for the draft survey, she was always safely loaded.

I gave never sailed as a mate on bulkers, so do not really know if the above actually works.

Dave Wilson
12th March 2008, 12:46
A lot of these practices were borne out of incompetence rather than design.
I have been instrumental in manageing dozens of Panamax/Cape Size in my time and would say practices eluded to above may have resulted in in the catastrophic loss record of this type of vessel. Combine above with alternative hold loading and you can get a feel for the situation.

Dave

gas_chief
19th March 2008, 14:33
I agree with Dave Wilson as to the incompetence aspect. The ship I referred to in my earlier post was about 250,000t dwt. The hatches on this ship were secured by hatch pins, but not tightened. You could see the gap between the packing and the compression bar in many places around the coaming! Main reason given for this was that the ship was on a regular Brazil to Rotterdam liner run. I brought up the question of seaworthiness on board, and boy did I get cold stares from everybody on board.

If we seafarer's do not take the issue of seaworthiness seriously, why blame the builders?

Well that was my last trip on a bulker. Had enough of that!

Bill Davies
21st March 2008, 01:04
Gas_Chief,
Blaming the builders is easy and always sits better than admitting to human error of those onboard. My post #18 in this thread was only half the story.
In order to protect the Master & Ch.Mate who were BOTH ashore at the time of the incident the 2/mate was not reported but went on to take the sister ship on her maiden voyage on his next trip only to put the that ship aground in the English Channel. Asleep in the wheelhouse chair rotten drunk. The German Master, a dear friend of mine, knew nothing of the former history but ended his seagoing career a 'wrecked' man. One of Brenda Silvers 'A' team.
Lost his Liberian License but kept his UK Certificate and went on to First Mates (FG) around 74. Tragedy.

Bill Davies
21st March 2008, 20:11
Gas_Chief,
Just re read my post last night and think it sounds ambiguous. The statement One of Brenda Silvers 'A' team.
Lost his Liberian License but kept his UK Certificate and went on to First Mates (FG) around 74. Tragedy. refers to the scouse 2nd Mate who caused the accident. Brenda Silvers ran a manning agency in Liverpool

Hope that is clearer.

Bill

Orbitaman
21st March 2008, 21:40
"Asleep in the wheelhouse chair rotten drunk. "

Is this documented evidence? Or hearsay? Or someones personal opinion?

Anything but documented evidence should not be posted. If this is documented, then it is a sad reflection on the Officer in question

gas_chief
25th March 2008, 16:17
Bill,

Well that sure is very interesting. Promotions in many cases I feel came as a result of time and being in right place, rather than out of competence. We have to tighten up our ropes. I have junior officers in the CCR in port who do not want to know about what is happing with the cargo. All they look at is the clock!

A few months back, I asked the Bosun to take a round of the deck to see if all the ballast tank hatches were secured on departure port. He reported back to me, "All secured Chief!". I went for my rounds after dropping off the pilot and found one open. When asked, all he has to say is - What's the difference if we leave just one open?

And this was one of our so called experienced Bosun's.

Bill Davies
26th March 2008, 00:17
Gas_Chief,
All understood. One of the most unnerving expressions used by foreign Mates & Engineers is 'No Problem'. Guaranteed to send me ballistic as experience taught me never to trust those using this expression. Having sailed almost exclusively with foreign crew for the last twenty odd years of service it quickly got around about my dislike for the expression and used to leave many of the poor souls tongue tied in looking for a substitute.

Brgds

Bill

James_C
26th March 2008, 00:41
I sailed with an Old Man (who'd been RFA previous) who had a similar problem with the word 'should', especially when asking as to whether something was/wasn't working/happening.
Being a word in everyday use amongst most English speakers it really got up his nose. Of course once word got about then EVERYONE started using it, dropping it amongst most sentences - used to send him purple...
Red rag to a bull and all that. (Hippy)
Then again, if you sailed with a Aussies, their frequent use of the term 'No Worries' (ingrained on the National psyche) as a replacement for 'No problem' could be an issue...

gas_chief
26th March 2008, 15:29
Coming back to the issue of hogging and sagging. I relieved a mate on a small gas boat(abt 11,000cbm) 2 years ago. This guy was deballasting tanks diagonally during the loading. i.e., 2p-3s together and 2s-3p together and so on. (This ship had cracks on the main deck extending diagonally from 4 ballast tank manhole inboards)

I asked him why not do a set of wings together and avoid the torsion. He gave me a run down on stability and the dreaded "FSC".

Later after taking over, I worked out the GMf and found that even with all tanks slack, the ship still had a GM of 2.3m. As I understand the ultimate objective is to have a reasonable ammount of positive GM. At least I think that is what the lecturers at South Tyneside College hammered into my head when I did my mates.

John Cassels
26th March 2008, 21:54
Coming back to the issue of hogging and sagging. I relieved a mate on a small gas boat(abt 11,000cbm) 2 years ago. This guy was deballasting tanks diagonally during the loading. i.e., 2p-3s together and 2s-3p together and so on. (This ship had cracks on the main deck extending diagonally from 4 ballast tank manhole inboards)

I asked him why not do a set of wings together and avoid the torsion. He gave me a run down on stability and the dreaded "FSC".

Later after taking over, I worked out the GMf and found that even with all tanks slack, the ship still had a GM of 2.3m. As I understand the ultimate objective is to have a reasonable ammount of positive GM. At least I think that is what the lecturers at South Tyneside College hammered into my head when I did my mates.

Was the free surface moment the same for # 2 and #3. If so , then you were
right to question him.

Bill Davies
26th March 2008, 22:54
GC/JC,
Whilst I share your concerns and agree in principle I would not have been unduly worried on such a small ship. Thinking back back it was years before I finally relinquished getting involved in the final figures. You only have to 'carry' a few incompetent Mates to change your out look for the rest of your life.


Bill

Derek Roger
27th March 2008, 00:13
GC/JC,
Whilst I share your concerns and agree in principle I would not have been unduly worried on such a small ship. Thinking back back it was years before I finally relinquished getting involved in the final figures. You only have to 'carry' a few incompetent Mates to change your out look for the rest of your life.


Bill

Bill ;
The ship had cracks on the Main Deck and you would not be worried !!!

I cant believe any Master Mariner would say such a thing .

Further why would a Master sail with incompetent Mates ?? Who's in charge ??

This boggles my mind .

Derek

Bill Davies
27th March 2008, 00:26
Derek,
I have sailed as Master on Cape Size Bulk Carriers in the Iron Ore Trade and experienced severe cracking and drilling on an almost daily basis. I have also experienced cracking in ULCCs where we have had to arrest the cracking in the usual ways. I do not think cracking on a small ship as indicated by GC would cause me any great concerns as the magnitude of cracking would invariably be less.

Unfortunately you have to sail with them first to discover their in competence and then 'sack them' as soon as owners can get them off.

And Derek, I was very much in charge!!!!

Bill

gas_chief
27th March 2008, 01:29
Hi,

Well about sacking, many companies employ people on voyage contracts and these guys are supplied by manning agencies. All the manning agency wants is the slot filled. In many cases sacked officers found their way back onboard very soon. (after a reprimand, not that it did them much good).

I have not yet worn the 4th stripe but I do wonder why the masters allow these guys to rejoin after getting sacked? One reason given to me by a master was, " If we refuse him, we will get another piece of c$#p!" So better put up with him.

Its the same with running the pumps and stuff. You get guys who overspeed the pumps to finish real fast. Join one of these ships after 15 years and boy is it fun stripping (I mean submersible and deep wells here).

Derek Roger
27th March 2008, 02:22
Derek,
I have sailed as Master on Cape Size Bulk Carriers in the Iron Ore Trade and experienced severe cracking and drilling on an almost daily basis. I have also experienced cracking in ULCCs where we have had to arrest the cracking in the usual ways. I do not think cracking on a small ship as indicated by GC would cause me any great concerns as the magnitude of cracking would invariably be less.

Unfortunately you have to sail with them first to discover their in competence and then 'sack them' as soon as owners can get them off.

And Derek, I was very much in charge!!!!

Bill

Bill

" Severe cracking and drilling on a daily basis " would not have allowed any prudent Master to continue without proper attention . The thread above was a Gas Tanker Loading !!!

A crack on the Main deck if propagated to the shear stake inevitably ends up the the vessel breaking its back .

A Vessel with deck cracks as you describe ( severe ) would require Class and Reg Body approval for a temporary repair which would involve the Drilling and arrest of the Crack / Cracks And the addition of sufficient deck strengthening to allow a safe voyage to a Repair facility to correct the problem .

The work would have to be done after gas freeing to allow a " Hot Work " permit or in the case of vessels with inert Gas Systems the tanks could have been inerted or pressed up with ballast . ( All very time consuming and expensive )

I can not believe you or others would sail around with a vessel full of cargo or otherwise and " Willy Nilly " be content to drill out the ends of cracks as you have described .

Certainly if one were to give such answer to an examiner while sitting ones ticket one would be sent back to sea as a penalty .

Inert Gas Systems are fairly new and at your time at sea were most likely not available .

Even minor cracks on tankers around the bilge keels and in the tanks around tripping brackets were considered major events and great care was taken with their repairs in all the shipyards I have worked in over the years since swallowing the " Pick " .

Derek

gas_chief
27th March 2008, 02:50
Was the free surface moment the same for # 2 and #3. If so , then you were
right to question him.

No 2 and 3 wbt were exactly the same in contruction. 3p/s wbt was about 100cbm greater in cap than 2 else the same (even the same corection for Free Surface.

Coming to think back, another reason the guy gave me was "to keep her at even keel through the loading". #2 had her LCF fwd of midships and 3 had it slightly aft, so by doing that they were able to maintain the vessel at even keel.

I never cared much for the trim during cargo ops, kept it +/- 1 metre till half and hour before topping off and that was when I brought her down to even keel. But this is one thing that I have seen a lot of mates do; i.e., to take off the trim correction from the hourly figures. OK before with the oold loadicators (kockums etc. with the windy windy things), one had to go into the tables to get the trim correction for each tank, but now with online computer based programs which automatically calculate capacities with the trim correction incorporated, why bother?

Bill Davies
27th March 2008, 10:13
Gas Chief,
I have to assume you are sailing in a highly regulated /unionised regime. Probably have ITF and such breathing down your neck. Throughout my command time (35 years (1970-2005) I would quickly dispense with a Mate who was ballast and sail shorthanded rather carry an incompetent individual.
In the 70s I loaded ULCCs due to removing a Ch.Mate on arrival Ras Tan/or similar and his replacement joined the following port. NBC it was probably one of the last companies where the Master exercised supreme authority and it suited me.

Bill

John Cassels
27th March 2008, 10:28
Derek ; "Inert gas systems are fairly new " ? , come now - , they have been
in regular use for over 30 years. Even I sailed with them during my tanker
years which wasn't yesterday !.

John Cassels
27th March 2008, 10:33
Gas chief ; Don't forget that there was a time ( sigh , sigh ) when a Kockum's
loadmaster and whessoe guages where state of the art , modern gear.

Bill Davies
27th March 2008, 10:43
Derek,
Where do I start!.......Chronologically?
1. The thread title is 'Hogging and Sagging' and the following is a natural consequence (still on thread)
2. Severe cracking iwo hatch corners were common partculary on OBOs & O/O and crack arrest was common place.
3. Well conversant with class requirements
4. Believe it. Needs must and when required to do work 'Willy Nilly' we did it.
5. Examiners are fine (in the classrom)..... mind you I have a lot more to say on this in light of present day examiners with Class 1 and no command experience. What happened to Extra's
6. Inert Gas experience? They were around a lot earlier than you obviously think and give me a break I'm 68 not 98.
7. Bilge Keels etc, were outside my remit as I could never hold my breath long enough for a 24.6mtr dive.

Derek, with greatest respect you seem a little naive about what was actually happening out there in ships. (some the largest afloat at the time).

I sense you are coming from the a class surveyor /shipyard background following your departure from Brocks. Believe me there was another world out there.

Oh and by the way 'greatest respect' was meant as the last time I used that in 'Riverdance ' I understand my fan club came out in force.

Regards

Bill

Bill Davies
27th March 2008, 10:49
John Cassels,

Time to get our zimmer frames out John

Bill

John Cassels
27th March 2008, 11:01
John Cassels,

Time to get our zimmer frames out John

Bill

Mine is classed with GL , how about yours Bill ?.

Bill Davies
27th March 2008, 12:47
John,

You're a lucky man. I'm with Hellenic Register (with trading limits- the local and back!). I could not stretch to anything more.

Bill

gas_chief
28th March 2008, 13:07
Gas Chief,
I have to assume you are sailing in a highly regulated /unionised regime. Probably have ITF and such breathing down your neck. Throughout my command time (35 years (1970-2005) I would quickly dispense with a Mate who was ballast and sail shorthanded rather carry an incompetent individual.
In the 70s I loaded ULCCs due to removing a Ch.Mate on arrival Ras Tan/or similar and his replacement joined the following port. NBC it was probably one of the last companies where the Master exercised supreme authority and it suited me.

Bill
HI Bill,

No comments on the type of setup I am with now. But off late I have been getting to relieve or to hand over to people who look at you and say, "why are you bothered mate?".

Again it comes down to a question of quality. I do know if we can call it incompetence. Cuz I feel regardless of where poeple are from they do learn the same stuff at college. It's how much of it they actually apply when they come back to sea?

Now that's when the manning departments can make a difference by selectively recruiting. But unfortunately that is not the case. With every company swweping for officer's we are going to go this way. If you go to ASDA(or COLES here down under) and buy "smartprice" stuff, that's exactly what you get "smart-quality". You've got to look harder if you want better. With salaries going up in most countries now, compnies have got to be more selective in their intakes. I feel that can be the only solution.

Well this thread has moved from hogging and sagging. Well anyway's life goes on. Back to sea in a few weeks.

gas_chief
28th March 2008, 13:12
Gas chief ; Don't forget that there was a time ( sigh , sigh ) when a Kockum's
loadmaster and whessoe guages where state of the art , modern gear.

Well John,

We still have ship's sailing around with the good old windy windy kockums and whessoes. Nothing against them. They are great.

But the new stuff make life that much more easier when you end up having to do a lot more stuff by oneself. (like when you get junior's who keep a watch on the CCR clock in port, mobiles while entering harbour,and the iPOD's when at sea)

Bill Davies
28th March 2008, 19:45
Gas_Chief,
Cuz I feel regardless of where people are from they do learn the same stuff at college.Lets not go into the semantics of what they learn in college as what I have experienced in the last 10/15 years is a joke.
The manning departments will make no difference as they are drawing on the same pool. We need to return to the type of training much of the membership of this site endured. Hogging & Sagging?? I'm distraught!!

Brgds
Bill