[Derek Roger]

The controllable pitch propeller was invented in Rothesay New Brunswick at that time for aircraft propellers ; gentlemans name was Wallace Turnbull .It was first tested in flight in 1927. At that time it was patented as a variable pitch propeller .

 

[Varley]

I 'felt' that date much too late and related to aircraft developments. One can Google a reference to a variable pitch propeller of 1849 by Griffiths and wonder if another member can do better.

I am also sure that the technique was used in small boats for altering direction (presumably after the introduction of the internal combustion engine as reciprocating steam was easy enough to reverse on the prime mover).

Altering blade angles, 'on the move' as it were, would not have taken the marine fraternity by much surprise as later paddle technology had several variations on the theme.

 

[Bill Morrison]

KaMeWa V.P.P.
From memory the only problem we had was the forming of microbes in the hydraulic oil which rendered the system inoperable. I think it was a Shell oil but can't remember type or grade. The main spring set the blades to full ahead thus giving some control. Having a bow thruster help with manoeuvring.

The diagrams have some information of the system.

 

[sternchallis]

Thanks Bill,
Allways wondered how these worked, even though I have seen a few stripped down in the drydock. I was probably a bit young at the time to ask or understand as a 17 year old apprentice. The fitters wouldn't have known, we always had a makers man down to supervise and do critical parts.
Most of the CPP 's were Stone Manganese Marine, but same design.

I remember once they opened one up and boss on which one of the blades was attached had cracked in the step section , ie at the base of the small diameter boss.
Now if that blade would have come off at speed it would have spoiled somebodies day and probably holed the hull. My guess they probably caught a bit of ice.
Stern trawler up in Greenland or Barents sea.

 

[uisdean mor]

Thanks Bill,
Allways wondered how these worked, even though I have seen a few stripped down in the drydock. I was probably a bit young at the time to ask or understand as a 17 year old apprentice. The fitters wouldn't have known, we always had a makers man down to supervise and do critical parts.
Most of the CPP 's were Stone Manganese Marine, but same design.

I remember once they opened one up and boss on which one of the blades was attached had cracked in the step section , ie at the base of the small diameter boss.
Now if that blade would have come off at speed it would have spoiled somebodies day and probably holed the hull. My guess they probably caught a bit of ice.
Stern trawler up in Greenland or Barents sea.

On a similar vein - Houston Ship Canal. Making a turn in darkness to move back down when we encountered a loose channel buoy and a subsequent amount of heavy duty chain. Single screw KaMeWa but twin engine Peilsticks. We lost one blade due to fractured boss and when we drydocked it became obvious the actual hub was also damaged beyond repair.. At the time we were motoring (sic) on one engine as the other one was stripped down for removal of the main crankshaft due to a crankcase explosion leaving Chittagong. I do not know what I did with my spare time on that ship. (K)

 

[sternchallis]

Hmm,
Some people get all the fun!

Pielsticks, goodness me what had you done to deserve being landed with those.

As one old chestnut says, "Never join a ship with an engine begining with "P", such as Paxmans, Pielsticks and PDoxfords".

They wouldn't know they are born the engineers of today on some of the engines and situations we had to put up with in our day.

 

[Derek Roger]

On a similar vein - Houston Ship Canal. Making a turn in darkness to move back down when we encountered a loose channel buoy and a subsequent amount of heavy duty chain. Single screw KaMeWa but twin engine Peilsticks. We lost one blade due to fractured boss and when we drydocked it became obvious the actual hub was also damaged beyond repair.. At the time we were motoring (sic) on one engine as the other one was stripped down for removal of the main crankshaft due to a crankcase explosion leaving Chittagong. I do not know what I did with my spare time on that ship. (K)

Mahsud or Maihar Hugh ?

 

[uisdean mor]

Mahsud or Maihar Hugh ?

Maihar - Charlie Bald flew out to Galveston to run the drydock - which did not go well as they knew they had us over a barrel. Hub had to be manufactured back in Sweden which took some time. In that time the crankshaft was replaced. I flew home from Galveston towards the end so did not experience sea trials - which I am sure were a test of nerves. Lots of crankcase time on the Pielsticks as also stood by the tankers as the Napiers were changed out for ABB and we took the chance of updating all main engine work. If memory serves me right I think we trialed a new version of exhaust valve body during that time as well. All a long time ago.

 

[uisdean mor]

Hmm,
Some people get all the fun!

Pielsticks, goodness me what had you done to deserve being landed with those.

As one old chestnut says, "Never join a ship with an engine begining with "P", such as Paxmans, Pielsticks and PDoxfords".

They wouldn't know they are born the engineers of today on some of the engines and situations we had to put up with in our day.

Interesting work all the same. Once the decisions are made re what needs doing then a plan falls into place and we work through it. Some satisfaction in overcoming the logistics and being able to run the plant as close to what it should do. Albeit with Peilsticks the wear rates were so bad that good times never lasted long. Character forming??? There were worse times to come with Russian designed , Yugoslav built B&W and more V18 Peilsticks. But that is another story as they say

 

[Don A.Macleod]

Mahsud or Maihar Hugh ?

Very interesting and in contrast we arrived at Houston from Japan (late '69 on Mahsud) tugs were on strike but as we had CPP and bow thruster we were allowed to go up the canal under our own"STEAM". It was early evening but dark and when the old man (Watson Ross) came down to the bar after docking he said the pilot was very impressed with our manouverability. Wonder if it was the same pilot Hugh!

 

[Bill Morrison]

This has turned into a very interesting discussion started by " Old Strawberry."
As KaMeWa is the only type I have had any experience of, I was surprised to come across an advert while browsing in The Motor Ship of July 1947. It was for a Rotol variable pitch & reversing propeller for a small harbour tug, will down load it.
I have also been searching the internet for information on Rotol Ltd Gloucester. The only thing seemed to be the aviation industry, no marine side and then came across this post. Saunders Roe (Anglesey) MTB 539 it contained mention of a Rotol propeller. This is one for the R.N. boys but really worth a look. dave-mills.yolasite.com/saunders-roe-mtb.php
Bill

 

[uisdean mor]

Very interesting and in contrast we arrived at Houston from Japan (late '69 on Mahsud) tugs were on strike but as we had CPP and bow thruster we were allowed to go up the canal under our own"STEAM". It was early evening but dark and when the old man (Watson Ross) came down to the bar after docking he said the pilot was very impressed with our manouverability. Wonder if it was the same pilot Hugh!

Hello Don . sorry no idea of the pilot. Master was - I want to say Dennis?? MacManus but could be wrong. The interesting bit about the whole escapade( for a Stornowegian such as yourself) was that on the way over we called into Mombassa for tea and Johnie Bain flew out to "verify" that the crankshaft was actually bent. There was a train of thought that they were relatively short and robust that yes then could be damaged surface wise but not bent. Well this one was bent and "scratched". Spent two days in and out of the crankcase with Johnie and he eventually agreed. After that he did treat us to a night out up the town. Met him a few years later on Goat Island when I was working as engineer on the Mallaig purser Silvery Sea. But that as they say is another story. Slainte

 

[Steve Oatey]

A bit of a misnomer here ; almost all propellers have a variable pitch unless is is an Archimedes screw .
What is being discussed is a controllable pitch propeller ; two different things .
A controllable pitch prop also has a variable pitch .

Not knowing the difference is a good way to fail Chiefs orals . Derek

Agreed Derek. The wind is often described as "light,variable" but that does not mean it can be altered. They're known as CPPs for a reason.

 

[BOB.WHITTAKER]

Variable Pitch

We all know exactly what is being refered to as " Variable Pitch " in
this thread .

 

[Don A.Macleod]

Hello Don . sorry no idea of the pilot. Master was - I want to say Dennis?? MacManus but could be wrong. The interesting bit about the whole escapade( for a Stornowegian such as yourself) was that on the way over we called into Mombassa for tea and Johnie Bain flew out to "verify" that the crankshaft was actually bent. There was a train of thought that they were relatively short and robust that yes then could be damaged surface wise but not bent. Well this one was bent and "scratched". Spent two days in and out of the crankcase with Johnie and he eventually agreed. After that he did treat us to a night out up the town. Met him a few years later on Goat Island when I was working as engineer on the Mallaig purser Silvery Sea. But that as they say is another story. Slainte

Hi Uisdean from the glorious Isle of Lewis and just finished demolishing a plateful of newly caught Stornoway herring! Tried to visualise you and Johnnie Bain together in a Pielstick crankcase! You desrved a medal for that!

Didn't kmow him very well as I only did a couple brief spells on the coast with him but he was a high quality man, everything had to be perfect I believe.

To establish that a Kobe Steel c'haft was bent took some precsiion work. Must have been some "bang ". Do you ever come up this way nowadays?

Slainte Donald

 

[Derek Roger]

My last trip on a Tanker was Lustrous Dubai to Stendngsond ; Johnny was the super who met us there . He took me out for a very nice dinner before I flew home and all the conversation was about the turbo chargers . At the end I think I had him convinced that a retrofit to Brown Boveri would solve a lot of the charter speed problems .
The next time I saw him was when I resigned to emigrate to Canada ; he did his best to try and make me change my mind and again provided a very nice dinner . No regrets ; who was to know then what was about to happen to the Brocks fleet ?
I always got on well with John ; he was a good engineer . Last I heard of him he was a "Big Wig " in the Highlands and Islands development board .


Cheers Derek

 

[uisdean mor]

Hi Uisdean from the glorious Isle of Lewis and just finished demolishing a plateful of newly caught Stornoway herring! Tried to visualise you and Johnnie Bain together in a Pielstick crankcase! You desrved a medal for that!

Didn't kmow him very well as I only did a couple brief spells on the coast with him but he was a high quality man, everything had to be perfect I believe.

To establish that a Kobe Steel c'haft was bent took some precsiion work. Must have been some "bang ". Do you ever come up this way nowadays?

Slainte Donald

Hi Donald , Good to hear from you. Sadly flying a desk these days and rarely get round my old haunts. The talk of the steamie is all broadband and bespoke solutions to suit geography and climate. Working quite a bit with academics on peatland and carbon sequestration and if the latest Barvas buy out completes then maybe there might be room for a wee visit. There may also be a project brewing in Skigersta so you never know. You make me envious with the herring but not to be outdone an old uncle of my wifes has found a source of sea trout not far from the croft and I am going to have a few days down with him next week. I like the finnocks best but he tells me the average is about 2 lbs - so reasonable fish. I will let you know how I get on. Slainte

 

[littoralcombat]

To clarify, Controllable Pitch Propellers are those (the clue's in the name) whose Blade Pitch can be Mechanically altered (controlled) whilst underway. The term Variable Pitch refers to those Props whose Blade Pitch can be adjusted, but not during operation, i.e the individual blades can be rotated on the hub to 'Fine Tune', probably no more than a few degrees, in order to get maximum efficiency (in dock or alongside only). Even with today's complex computer modelling, nothing can predict the exact performance of the 'Real Deal' once installed.
I believe the Props for the two new RN Carriers have this feature.

Regarding Emergency situations, the RN CPP on the Type 21, 22, 42 classes had a feature that, in the case of of a Hydraulic failure (blown seals somewhere), the pitch could be altered and locked in a usable state to get home. This involved mechanically turning the Oil Transfer Tubes running from the Oil Transfer Box on the Gearbox to the Hub, which in turn would move the actuator and rotate the blades. In practice though, there was a huge amount of stress and twisting of the Tubes and use of this was virtually forbidden in Peacetime unless in extreme situations. Better to get a tow rather than risk severe damage to the mechanism.

 

[A.D.FROST]

There are that many variable answers and getting out of control,so I thought I would pitch in with two adds from 'Shipbuilder' Marine Engine -Builder of Jan 1959.So you pay's your money and take your choice. CCP or VCP

 

[Varley]

#38. The last (and only) time I had anything to do with a vessel with such facilities it was a matter of fairly strict 'convention' they be referred to as adjustable pitch. Controllable and variable are in common usage for the 'normal' animal.

Should anyone design a propeller with a variable attribute similar to the meteorological meaning in "winds light to variable" or indeed a method of making the wind controllable as with a "controllable pitch propeller" I have no doubt the semantic distinction would become more important.

If this is a P&Oh or The Cunard versus the rest which is to be the posh description and which the peasant?