rogerthebodger
Well-Known Member
That's why I designed and built my own
That's why I advocate an all metal rudder. If the OP is happy with his current setup so be it.
New grp spade rudder
- Thread starter Daydream believer
- Start date
That's why I designed and built my own
That's why I advocate an all metal rudder. If the OP is happy with his current setup so be it.
Seajet
...
I don't think the OP has a set-up without any failures, which is why this thread exists !
Yes the A22 has an all stainless full length pintle & fastenings, with a solid iroko 1 piece rudder; after 36 years of use, I can say I wouldn't have anything less.
As for the Airbus, that's nasty carbon fibre & alloy, maybe - maybe - fit for a hopefully highly maintained aircraft - avoiding salt water - with regular lots of inspections inc ultrasound, then the wing or aircraft is binned after so many flight cycles, which is not the chosen career path of aspiring yots.
Yes the A22 has an all stainless full length pintle & fastenings, with a solid iroko 1 piece rudder; after 36 years of use, I can say I wouldn't have anything less.
As for the Airbus, that's nasty carbon fibre & alloy, maybe - maybe - fit for a hopefully highly maintained aircraft - avoiding salt water - with regular lots of inspections inc ultrasound, then the wing or aircraft is binned after so many flight cycles, which is not the chosen career path of aspiring yots.
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Tranona
Well-Known Member
So, I guess you are now going to claim that you know more than the biggest manufacturer of steering systems in Europe and most of the major boatbuilders as in TSB240's list. Not sure what walking out on an alloy plank has to do with subject - who on earth would want to do that?
You make think you know (or used to know) a lot, but I suspect that all the clever people who work for Jefa and the design offices which specify their products know just a little bit more about their specialised subject than you.
BTW I do not claim any special knowledge on the subject, but do respect people who do.
Tranona
Well-Known Member
You will find a useful discussion on aluminium stocks and corrosion in the report of the loss of the rudder on Megawat, a Hanse 37 of similar vintage to yours. The report was published in 2006 by the MCIB (Irish equivalent of MAIB). It is on their site www.MCIB.ie
tawhiri
Well-Known Member
Calm down guys
I have a 301 as well and did look into a new rudder last year due to the pitting problem mentioned. Kohlhoff in Hamburg was recomended to me, and I was told he could only supply a rudder over winter, after the summer rush. The problem is well knowen by Hanse, apparently the rudders were produced in Poland. I would have no problem getting Alu again because I don't beleive my boat will be still floating in 20 years time. However I have just ignored the issue for the time being.
I have a 301 as well and did look into a new rudder last year due to the pitting problem mentioned. Kohlhoff in Hamburg was recomended to me, and I was told he could only supply a rudder over winter, after the summer rush. The problem is well knowen by Hanse, apparently the rudders were produced in Poland. I would have no problem getting Alu again because I don't beleive my boat will be still floating in 20 years time. However I have just ignored the issue for the time being.
Seajet
...
OK then...
Daydream believer
Well-Known Member
You have hit the nail on the head here. As far as i am aware the aluminium stock is ok.
What i believe has happened is that at the manufacture stage hanse fitted the rudder off a 34 series boat
From our hanse forum dimensions of the deep draft riudder are the exact same as mine.
I suspect they either tried to standardise rudder sizes ( although that may be wrong as some 31 series have a number of different rudders) or ran out of 31 rudders. & stuck a 34 on my boat. My draft is 1.75 & the rudder is 1.68.
Infact as it starts below waterline it comes almost to the bottom of the keel. This makes it extremely vulnerable to damage as in my case .
My new rudder is being made 100 mm shorter
As for the argument about rudder stock material it is irrelevant as my one seems ok
As for an entire rudder in stainless i would take issue. First. ( & not wishing to cause insult) the owner of a steel yacht is not looking for performance. if he wanted a performance in metal yacht he would go to a dutch builder & have it in aluminium & it would not be a chine design. the dutch used to ( probably can still do) build the best ally boats in the world. Of you want proof look at some of the early admirals cuppers - Noryema comes to mind for those who go back that far. Quite honestly some steel boats i have seen might just as well have a plank of wood stuck 10 ft out the back instead of a half inch metal plate most seem to have
Next --strength
If one increases the strength of the rudder what effect does that have on the rest of the structure. It seems that my top bearing has been damaged because 2 of the needle rollers have been sheared off by the top of the stock pushing forward. Now say that had been a really hard grounding. These bearings are standard throughout the industry so one cannot blame the bearing. I think i would prefer a bent stock as to having the stern ripped out of the boat. If you increase one bit you have to increase the rest. & then we are back to the steel boat. Which i would never have.
Finally comment has been made about the hanse that lost its rudder & subsequently sank.
The shaft broke because after manufacture the owner had it adapted & a groove machined in the shaft for a particular coupling. The shaft broke as it had not been designed for this alteration. The boat sustained further damage. & was abandoned. Certain schools of thought is that it could have been rescued if better efforts had been made by those on board & those rescuing had tried harder. I cannot comment either way although i might have let it sink in the same instance
The interesting thing is that the owner immediately ordered another new boat of the exact same model.
So he was happy enough
I am more than happy with my hanse. It was built at a time when they began to care about what they were building. Now i suspect it is just a bunch of assemblers making a product. That being said for its price a hanse has a lot of technical thought put into it is still a good buy if bought from the right dealer
Apart from the length the rudder will be as original. Perhaps with a bit more grp around the joint!!
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Seajet
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Alloy is fine on aircraft, one is basically stuck with it; as I mentioned before, aircraft have finite lives, boats are expected to last - by me, anyway ! - and may endure all sorts of conditions their designers didn't dream of.
Ask any engineer worth his salt which material he would prefer to use for a rudder stock; I'm surprised Halberg Rassey use alloy - if that's true - but there must be more to that story.
Ask any engineer worth his salt which material he would prefer to use for a rudder stock; I'm surprised Halberg Rassey use alloy - if that's true - but there must be more to that story.
onesea
Well-Known Member
Last how long? Is the question 10 years 100 years???
Many boats now are little more than consumables, worth less than the sum of there parts... Sad but true..
rogerthebodger
Well-Known Member
If the OK is very happy with the way his Hanse is designed good luck to him.
For the record I spent 20+ years working as a mechanical / Electrical engineer having a degree in mechanical engineering and becoming a C Eng M I Mech E before retiring.
My boat is a cruising boat and not designed for racing so I am happy with a single chine hull design and my rudder is not a half inch metal plate, it had the proper NACA profile fabricated.
Aluminium boats are fine but proper aluminium welding needs quit a lot of skill and proper costly equipment. If I did have an aluminium boat it would have a fabricated aluminium rubber and stock. If I had a GRP boat seeing the repairs to GRP rubbers reported an this and other fora I would again have a steel/stainless steel fabrication.
A spade rubber by it very design is subject to damage in any grounding due to it cantilever design, also the shock loading of the bearings would be much higher than a skeg mounted rubber like mine.
With production boats like most AWB's there is a cost pressures, when I built mine that was not anywhere the cost pressures production boat builders have.
There has always been disagreement between steel and aluminium boat builders at to the best material for a custom build boat which a metal will always be. To the absolute best material is Cupro nickel but the cost would be out of this world.
" Many boats now are little more than consumables, worth less than the sum of there parts... Sad but true.. "
That is true about production boats but not so true about custom boats.
For the record I spent 20+ years working as a mechanical / Electrical engineer having a degree in mechanical engineering and becoming a C Eng M I Mech E before retiring.
My boat is a cruising boat and not designed for racing so I am happy with a single chine hull design and my rudder is not a half inch metal plate, it had the proper NACA profile fabricated.
Aluminium boats are fine but proper aluminium welding needs quit a lot of skill and proper costly equipment. If I did have an aluminium boat it would have a fabricated aluminium rubber and stock. If I had a GRP boat seeing the repairs to GRP rubbers reported an this and other fora I would again have a steel/stainless steel fabrication.
A spade rubber by it very design is subject to damage in any grounding due to it cantilever design, also the shock loading of the bearings would be much higher than a skeg mounted rubber like mine.
With production boats like most AWB's there is a cost pressures, when I built mine that was not anywhere the cost pressures production boat builders have.
There has always been disagreement between steel and aluminium boat builders at to the best material for a custom build boat which a metal will always be. To the absolute best material is Cupro nickel but the cost would be out of this world.
" Many boats now are little more than consumables, worth less than the sum of there parts... Sad but true.. "
That is true about production boats but not so true about custom boats.
Daydream believer
Well-Known Member
So it was you that stuck the plug socket behind the radiator!!:encouragement:
Tranona
Well-Known Member
Suggest instead of guessing things you do a bit of reading and you will get the "story" The explanation of the alloy that is used and why most builders use aluminium in preference to stainless is freely available on the Jefa website - as is information on how to minimise corrosion on both aluminium and stainless shafts. You might also read the ABS guidelines on the construction of rudders for offshore yachts. These guidelines are extensively used by designers to meet the RCD, including Judel and Vrolijk who designed the Hanse.
Tranona
Well-Known Member
That is not strictly correct, as, although the fitment of the autopilot was suspected, the report on the shaft (which was recovered) was inconclusive and there were other aspects of machining that were also suspect. The sinking occurred because the rudder dropped out and the top of the tube was below the waterline - and not separated by a watertight bulkhead from the rest of the boat.
At the time of the report there had been no other reports of failure of that type of shaft. You are right to have confidence in your boat's design. You seem clear about what broke and the cause - which does not seem to be related to the material of the stock and frame. However, that does not stop people some getting on their hobby horses.