Rudder Failures

[Polux]

Originally Posted by downunder

Smackdaddy,

I recall a fair bit of discussion on this forum of rudder failures with Hunters.
search the forum.

There is also the rudder failure that contributed to the abandonment of the brand new first Alpha 42 catamaran.

The Hunters of a certain vintage had a design problem. It seems to me that happened only on those boats. I have no notice of modern Hunters losing their rudders. Someone has?

I have the impression that even on the Hunters that lost the rudder that happened not when they were new, but after many years of use. That problem can have been incremented by lack of appropriate maintenance. Am I wrong?

[smackdaddy]

Originally Posted by downunder

Smackdaddy,

I recall a fair bit of discussion on this forum of rudder failures with Hunters.
search the forum.

There is also the rudder failure that contributed to the abandonment of the brand new first Alpha 42 catamaran.

Yeah, I've seen people talking about a "spate of them during the 90's" or something like that. I've never heard actual numbers and/or circumstances - but I don't recall it being a real widespread problem. And, regardless, I always take Hunter bashing on forums with a HUGE grain of salt. It's the "thar be dragons" subject of forums that gets incredibly goofy in most cases.

For example, here is a pretty good article on rudder failures that mentions a Hunter 450 in the 2000 ARC - but also details losses on many other boats:

Rudder failure - how and why it happens.

A French yacht called Zouk – a 43ft Jeanneau Sun Odyssey belonging to the Glenans Sailing School – had lost its rudder and has been adrift for nearly a week. Attempts were made to tow the stricken yacht but to no avail. Her crew were taken off and Zouk was scuttled so she would pose no threat to other mariners...

An isolated mishap? Not really. Rudder failure raised its embarrassing head again. In the Atlantic Rally for Cruisers (ARC) of 2002, a Hunter Legend 450, known as F2, met a similar fate and, after initial support from three other entrant yachts, reinforcements arrived in the shape of … would you credit it … Tenacious! Taking advantage of their saviour’s comprehensive workshop, a jury rudder was fitted and F2 was on her way.

Onwards to the ARC of 2006 and the story quickens. This time Y Not, a Contest 48 and Arnolf, a Bavaria 35, both found themselves rudderless. Y Not made it safely to St Lucia but unfortunately Arnolf proved unmanageable and was abandoned.

In the course of my research for this article, I heard of other rudder failures, including a Catalina 42, J44, Wylie 38, Hunter (Legend) 466, and a quartet of Cal 39s. I have personal knowledge of an Excalibur 36 (I built its replacement rudder), a Rival 38, a Dehler 34, a couple of Trident 24s, various Westerlies and some earlier Moodys.

When you think of how many boats there are out there, this is hardly a mechanical epidemic, but considering how important rudders are in the general scheme of things it’s certainly a cause for concern. Most were spade rudders, and the most common failures saw stocks breaking where they emerged from the hulls – always areas of highest stress concentration. It’s this type we’re mainly concerned with here.

So, it's not like any boat is immune. And it's not a problem unique only to Hunters or other production boats. There are plenty of "bluewater" boats on that list.

I think Paulo is exactly right...it's primarily poor maintenance. People seem to look at the rudder and think of it as part of the hull (in terms of care) - like the keel - instead of a completely different, very active, system that needs to be maintained far beyond bottom paint.

Then, as I've said earlier, you add AP into the mix and in rough conditions you can get pretty aggressive use through the steering system. Combine these - and things can go south pretty quickly.

[Stumble]

Originally Posted by Polux

In fact carbon is a better material for it and carbon is used extensively for that in racing boats. The reason it is not used in cruising boats is price even if some expensive cruising boats have them in carbon.

Titanium was used on a keel of an Open 60 and it proved to be a bad idea...it broke without any impact while the carbon ones resisted breaking only under a big impact. When it broke it had already some years of use. It seems it had something to do with stress metal fatigue. Off course it would be better than a stainless steel one but the cost would be hug, certainly bigger than carbon.

The reason titanium isn't used is because despite titaniums massive strength to weight ratio, it has about the same stiffness as aluminium. Rudder stocks like masts don't really need to be all that strong, but they need to be immensely stiff to keep from bending. You could certainly make one from titanium, but it would be about the same size as an aluminium stock (ie much bigger than a stainless one) weigh about the same, and cost more... Though the cost wouldn't be terrible, titanium extrusions like this would run about 15% more than a stainless extrusion of the same size.


As for the titanium keel... While titanium is a questionable material for keels in some regards (stiffness again) the open 60's keel looked nothing like what a normal boat has. It was a hollow foil with internal webbing for stiffness designed to move as much weight as possible into the bulb. It failed because it was under-engineered compared to the loads, it had nothing to do with the materials.

Frankly there are a lot of good places for titanium on a boat (I used to sell it), but rudders aren't one of them. Carbon fiber is really a better option here, or one o father super-autensic stainless alloys.

[Polux]

Originally Posted by Stumble

....


As for the titanium keel... While titanium is a questionable material for keels in some regards (stiffness again) the open 60's keel looked nothing like what a normal boat has. It was a hollow foil with internal webbing for stiffness designed to move as much weight as possible into the bulb. It failed because it was under-engineered compared to the loads, it had nothing to do with the materials.

...

From the investigation report:

"The investigation was able to exclude the possibility of a break due to a collision with an "unidentified floating object". It also noted that there were no metallurgical defects, and that the welds showed no anomalies that could explain the break. The investigation shows that the break was due to damage caused by metal fatigue, engendered by repeated shocks from contact with waves. "

[neilpride]

Originally Posted by smackdaddy

Yeah, I've seen people talking about a "spate of them during the 90's" or something like that. I've never heard actual numbers and/or circumstances - but I don't recall it being a real widespread problem. And, regardless, I always take Hunter bashing on forums with a HUGE grain of salt. It's the "thar be dragons" subject of forums that gets incredibly goofy in most cases.

For example, here is a pretty good article on rudder failures that mentions a Hunter 450 in the 2000 ARC - but also details losses on many other boats:

Rudder failure - how and why it happens.



So, it's not like any boat is immune. And it's not a problem unique only to Hunters or other production boats. There are plenty of "bluewater" boats on that list.

I think Paulo is exactly right...it's primarily poor maintenance. People seem to look at the rudder and think of it as part of the hull (in terms of care) - like the keel - instead of a completely different, very active, system that needs to be maintained far beyond bottom paint.

Then, as I've said earlier, you add AP into the mix and in rough conditions you can get pretty aggressive use through the steering system. Combine these - and things can go south pretty quickly.

So far so good maintenance isues and most cases shortcuts in materials and design, hollow cheap rudder stocks filled with crap, thin rudder layup filled with foams, weak internal structures, rudder post glued with crap to another crapy bulkhead , the list go on and on and on, bulletproof steering systems are a thing of the past in new production boats unless you want to pay the Price, Hunter made a big pile of dogshit in terms of boatbuilding shortcuts time agoo thats why is so hard to get rid off the past and even today there is still isues, Beneteau, Bavaria, Jeaneau ,Catalinas, Dufours, etc..

Look ,,, im involved in the restoration of 2 beneteaus right now after hurricane Gonzalo strike St Marteen, one is a Brand new Oceanis 50 , the other is a 45 same vintage, the 50 get holed in the bow and in starboard side, stern is holed to, it take wáter, a lot, rudder is bend , if i remember a same Oceanis 50 get rudder post problems in the north atlantic this year, well trust me if i say that after inspect deeply all the interior damage and system i just reach the conclusión that beneteau want their customers to be screwed in some isolated spot in the blue ocean somewhere, Lame and sad....

[robert sailor]

No matter who the builder is, Benni or Hunter or whomever....when you pay the entry level price for a product, any product made, you do not get high quality as they simply do not go together, never have, never will. You may get good value and personally I believe you do but that's as far as you can reach. Bullshitting yourself is pretty common these days depending on what boat you chose. Anything made that floats yesterday or today can get across an ocean but when the **** hits the fan you may well find out the difference quality makes.

[HappyMdRSailor]

Holy SMOKE...

That was a tough read to catch up...

[poiu]

Originally Posted by Polux

They don't use them anymore on new models. I believe the fact they had used old designed rudders for so long had to do with the conservatism of their clientele that as all conservatives think old stuff works better and is more resistant. They were lucky in managing to convince sooner their clients that a modern keel is not dangerous and way better than a full keel or a modified fin keel. It seems that finally they manage that also in what regards modern rudders versus skeg rudders. All the new models have a very nice set of spade twin rudders, except the 545 but that one is a MKII and use the same hull of the old 54.

The Oyster 48 lightwave belongs to the Oyster past when they made some very modern boats and had a clientele that wanted modern fast boats. The fact that that 26 years Oyster is still a very fast boat says at how well that boat was designed. Unfortunately they did not sell many of them and understood that their future passed by a more conservative design, not to say older, that sell better in UK.

Regarding that Oyster 48 and the rudder breakage it is good to remember that boat is used exclusively as a race boat and make an huge number of races every year including transats and have certainly made hundred of thousands of miles. It remains to know if the rudder was still the original rudder. They, like masts and other stressed parts of the boat have a long duration, but not forever, specially if they are used in hard racing for many years.

With rudders, it is actually just the larger boats 67ft and up that have twin rudders unless you pick the lifting centreboard option, then you have to have twin rudders because there would be no point in the reduced draft keel with a deep rudder. In fact that is how Oyster started offering the twin rudder option, it was a result of the development of the lifting centreboard version of the 82 launched in about 2006. Since then they found the twin rudders work quite well and with the redundancy of two rudders the argument for having a stoutly built skeg hung rudder is less persuasive.

From a performance and control load standpoint they do make sense and I would be happy to own a twin spade rudder boat. With the failure of Scarlet Oyster's rudder the requirement for either a stoutly built rudder or redundancy from twin balanced spade rudders is made stronger in my view.

The Oyster Lightwave is not so much a fast design, but..guess what, a light boat. That is the main reason it is fast. I think the rudder being a spade is a small part of the picture. The hull shape is fairly conservative. The Scarlet Oyster is further fast because it is a tricked out version, well equipped, greatly modified for racing and sailed very well to boot. Oyster did try then and to sell light boats since, but they are not specially wanted. Seemingly people like the seaworthyness, smooth ride and stability of a heavier boat.

[robert sailor]

When you look at the stats about the actual use a boat gets it makes you rethink a few things. In San Diego over 80% of the boats never left their slip in a 12 month period and of those something like 5% actually went past the first buoy. So if my figures are close you have 95% of the boats (of which there are thousands) sitting around hardly being used. Then the very very few that actually go out in open water have a certain number of structural failures and everyone folds in the other 95% of the boats and says, well ya but its still only 1% failure rate but its 1% failure rate on 5% of the boats that actually go anywhere.

[poiu]

Originally Posted by robert sailor

When you look at the stats about the actual use a boat gets it makes you rethink a few things. In San Diego over 80% of the boats never left their slip in a 12 month period and of those something like 5% actually went past the first buoy. So if my figures are close you have 95% of the boats (of which there are thousands) sitting around hardly being used. Then the very very few that actually go out in open water have a certain number of structural failures and everyone folds in the other 95% of the boats and says, well ya but its still only 1% failure rate but its 1% failure rate on 5% of the boats that actually go anywhere.

Yep, a 1% failure rate is a colossally huge enormous number. If you multiply that by say a 30 year boating career and multiply it by say 20 to account for the unused fleet you mention the probability of failure for your actively used boat that is used in a career of boating goes to 600%.

It is the little numbers that kill you.

[a64pilot]

Accepting you guys numbers
What is the logic in building boats to a standard that only a few percent use?
Logic dictates that if the vast majority of a product line is used as weekend vacation houses, then the attention should be put into whatever makes them better weekend vacation houses.
Take the average SUV or half ton truck sold today, the trucks are very poor at hauling real loads and the SUV's are not good four wheel drive as in off road vehicles, because only a fraction of the initial purchaser uses them as such, the "luxury" items are far more important, that and styling because that sell vehicles, not off road prowess.
Boats are no different, I bet less than 1% that buy a new production boat do so with the intention of world cruising, and anything manufactured is done so for the initial purchaser, not the buyers of used products, and most mass produced items are considered good enough if they last through the warranty period.

[donradcliffe]

Its been an interesting thread, and here's my $0.02.

Its easy to determine the load on the AP if you have an analog ammeter on your DC panel. Just look at the DC amps as the boat sails and compare the peaks to the minimum. On my boat, if the peaks were more than 6 amps over minimum, it was time to balance the sailplan. The highest AP consumption I saw was not during gales, it was when I was beam reaching in 20-25k with full mainsail.

Fatigue is a real factor in rudder failures, and the ARC is a walk in the park compared to a circumnavigation. I knew two boats which had to be abandoned within 600 miles of completing circumnavigations due to rudder failures. In both cases they tried for 3 days to save the boat before they gave up.

I agree that probably half the rudders out there are full of water, and in many cases it is due to an inadequate seal between the shaft and the fiberglass. After having my rudder rebuilt, I took a dremel tool and ground some glass out at the joint and replaced it with 5200 which seemed to seal better. It would be nice to develop a non-destructive test for water in the rudders, as failure of the stainless armature is just a matter of time.

The loads on the rudder system from the AP include torque, which is independent of the attachment point of the AP and side load, which is not. However, lengthening the distance from the shaft to the AP ram attachment will also slow down the rudder response to the AP, which is definitely not a good thing.

For my boat, which had a 6 ft wheel and two turns lock to lock for +/- 40 degree rudder travel, I figured I could put lots more torque on the rudder with the wheel than with the AP ram, which was rated at something like 1000 pounds.

My AP ram was mounted on an aluminum plate which was bolted to plywood bulkheads. After watching things flex, I glassed a shelf to the hull to beef things up. The 10mm drive pin from the ram to the quadrant finally broke after 80,000 miles, so I ended up machining a 12 mm pin.

[a64pilot]

Originally Posted by donradcliffe

It would be nice to develop a non-destructive test for water in the rudders, as failure of the stainless armature is just a matter of time.

Ultrasound would absolutely tell you, I believe the coin tap test may well, and drilling a small hole will too I believe. I've seen a rudder or two actually swollen looking when the boat was in the sling and dripping water

[Polux]

Originally Posted by neilpride

...
Look ,,, im involved in the restoration of 2 beneteaus right now after hurricane Gonzalo strike St Marteen, one is a Brand new Oceanis 50 , the other is a 45 same vintage, the 50 get holed in the bow and in starboard side, stern is holed to, it take wáter, a lot, rudder is bend , ... well trust me if i say that after inspect deeply all the interior damage and system i just reach the conclusión that beneteau want their customers to be screwed in some isolated spot in the blue ocean somewhere, Lame and sad....

How do you expect to have credibility with statements like that?

You are recovering boats that suffer damage for impact or grounding after an hurricane and are surprised that a rudder is bent or that the boats sustained heavy damage? and from that you take the conclusion that :" beneteau want their customers to be screwed in some isolated spot in the blue ocean"!!!!!

[Polux]

Originally Posted by poiu

With rudders, it is actually just the larger boats 67ft and up that have twin rudders unless you pick the lifting centreboard option, then you have to have twin rudders because there would be no point in the reduced draft keel with a deep rudder. In fact that is how Oyster started offering the twin rudder option, it was a result of the development of the lifting centreboard version of the 82 launched in about 2006. Since then they found the twin rudders work quite well and with the redundancy of two rudders the argument for having a stoutly built skeg rudder is less persuasive.
...

What I have said is that all recently designed Oysters have not a hang rudder but twin rudders. That's true and the reasons are obvious to me and regards what I said in a previous post. After all they are just doing what other shipyards of well known bluewater boats (that in the past used skeg rudders) are making: designing better rudders, more modern and better sailing yachts.

One of then is Halberg Rassy that is not using skeg rudders anymore on the new designs, not even on its bigger boat, the 64 and they don't use twin rudders but a single spade rudder.

http://www.hallberg-rassy.com/filead...4TeknBeskr.pdf

What you say regarding big yachts not being able to use single spade rudders makes not much sense: they used before skeg rudders with the same dimensions than a spade rudder need and lot's of big yachts use single spade rudders.