Structural Faults with Modern Yachts

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Let them buy slow and stodgy I say, so what if their grins are not wall to wall like ours...

Robin

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Which is of course what the multihullers say. /forums/images/graemlins/grin.gif
 
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Birdseye wrote: "I agree. Its a boring subject that has been done to death a hundred times."

If your (sp you're) bored ..... you can go to another thread. This one interests me. /forums/images/graemlins/ooo.gif

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Well you've got an interesting few days in front of you then. Put "AWB" into the search engine and you will find the previous hundred or more inconclusive threads on the same subject.

That of course is the problem - there's lots of conflicitng opinions and prejudices in the old vs new debate, but precious little technically sound hard fact.
 
I sailed a 32ft Beneteau off the east coast of Africa. In Fact from Durban (South Africa) to Maputu (Mozambique) and back again. I am not sure how old the boat was at the time, I can find out if you like, but the one thing I noticed during the sail was the boat flexed a lot.

I had the dubious honour of the forepeak cabin and I as I lay on my bunk trying to get some zzzzz's I would watch the hull literally breath in and out. The hull seemed to move as much as 3cm's. I must admit I found this to be rather disconcerting. I must be fair and add that we were sailing downwind in apparent winds of around 45kts, ...We only had a tiny handkerchief of genoa out.....And the waves were probably at first spreader height and quite steep, anyway, the thing is that the boat was flexing a lot and I wondered how often one could submit the boat to treatment of this kind before the fiberglass started to give up.

Another thing that worried me about this boat was how difficult she was to sail downwind, she tried to broach at every opportunity, is this because of its design, or what? Other than that she was easy to handle in the marina under engine and on a beat, or fetch in 10 to 15kts true, you can trim her sails and tie the helm and she will sail on her own. But when you are sailing you aren't always guaranteed light winds, and more often than not you can find yourself in 25 to 30kt winds with rough seas, especially on a longish trip. Personally I am not sure of the longevity of modern bulk production boats.

On another point, I have friend who sailed on a 45ft Beneteau. The intention was to deliver it from Durban to Vancouver (Canada). I don't know how old the boat was, but she sure looked good.

Anyway, they foolishly left in front of a storm warning, hoping to get into the next port before the storm arrived. They didn't manage that and the skipper was not from South Africa and had not done his homework. When the weather hit them they had SW winds of 45kts true and climbing fast. He went out to sea instead of trying to motor like heck for port, or turn back and hightail it for Durban.

Of course he now was in the 'Agalus current' (sp) that sweeps down the east coast of Africa at up to 4kts from N-S. They were getting deeper and deeper into trouble. The further out they went the worse the wind against current got and of course the wind was rising all the time. By the time the Navy went out to rescue them, the inside of the boat had shredded. It became VERY dangerous to be below, the boat flexed so much that the inner panneling started to peel, splinter off, and fly around. Then, the saloon table also came loose and was being thrown around. By now the place was also covered in food, that had been spilled out from all the cupboards.

The sails were shredded, the rudder broke, the engine was swamped by rogue waves, the life raft was blown away when deployed, the painter was snapped as if it wasn't even there.

A ship tried to rescue them, but got a little close and bashed their mast. When they were lifted off the boat the winds were in excess of 90kts and the waves were ( according to my friend) higher than the mast. The only thing that enabled them to last long enough till the hellicopter arrived, was the ship. It sat to weather of them and so managed to calm the seas somewhat.

I am not sure if the mast went through the bottom of the boat, I tend to think not as she floated for two weeks and was a navigational hazzard during that time. BUT she absolutely trashed due to her flexing so badly, and definitely could not be sailed anywhere.
 
Wow ...... !!!! I have yet to sail down there .... but I do know that 30kts is the norm. /forums/images/graemlins/smile.gif

Your experiences are a lot different to the weekend cross English Channel croud that wont go out in 20+ knots.

Many thanks ...... and welcome
 
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That of course is the problem - there's lots of conflicitng opinions and prejudices in the old vs new debate, but precious little technically sound hard fact.

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Yes ..... I'm beginning to get that feeling too. I hope this post will be active for a few days more, just to see if the are some more hard facts out there.
 
Forgive me for doubting a 1st time poster with nothing in his bio to say who/what/where or boat owned but I have to say I am very impressed that you were able to sleep in the forecabin of a 32 foot Beneteau whilst going downwind in F9 winds and with seas at spreader height. I am amazed too that you were surprised at a tendency to broach under those conditions, I remember reading about boats that had even pitchpoled in similar conditions but then they were old fashioned long keeled heavyweights.
 
Thanks for that posting but I suspect that this sort of discussion people take the bits that reinforce their prejudices -so not to be outdone here goes:-

1. All boats are a compromise.

2 Modern boats sail well in average conditions and will survive a storm. Modern boats do slam more than long keelers.

3. Sails supplied on new boats are the cheapest possible.

4. Traditional long keelers track better in a sea but are slower and not so manoeuverable in marinas and are smaller and darker internally for any given length.

5. A friend who bought a long keeler as he thought the motion would be kinder is just as sea sick.

Here endeth the lesson!!
 
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The hull seemed to move as much as 3cm's. I must admit I found this to be rather disconcerting. I must be fair and add that we were sailing downwind in apparent winds of around 45kts

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I wouldn't be surprised if this was well within design specs for a 'modern' laminate.

my hull certainly flexes significantly at 25 - 35 knots. if fact many problems are associated with people creating fixed points in areas designed to flex which can lead to localised forces and failure................
 
Duncan wrote "my hull certainly flexes significantly at 25 - 35 knots. if fact many problems are associated with people creating fixed points in areas designed to flex which can lead to localised forces and failure................ "

I agree. I sailed a FP Tobago ..... hull sides used to pant and hit my elbow when I was on the bunk. I just moved further over ..... no real worries.

The problem with panel flexing is at the hard spots created by decks, bulkheads, internal joinery, etc.. And of course it wastes energy and doesn't make for an efficient hull.

Provided the rig, keel, and hull loads are transferred through a stiff framework ...... I can't see a particular problem.
 
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See Here for a report of a delivery trip in a new Jeanneau SO40 from France to South Africa which might be of some interest.

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Thanks for that. Despite it being from the Jeanneau site and hence bound to be pro-Jeanneau, it's good to remind ourselves that there are some good experiences out there. /forums/images/graemlins/ooo.gif

I note that they had to store 200 ltrs of fuel in there cockpit lockers. This suggests that the boat is not designed to sail with an extra 0.2 tonnes of load ..... especially in the cockpit lockers. Hopefully most of this was burnt off before they hit the rough stuff.

Note that the really testing part of the trip will be from Cape Town to Durban ...... so far they've just done the usually tradewind passage. The Durban trip is usual day sailing .... where the weather is unpredictable.
 
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Thanks for that. Despite it being from the Jeanneau site and hence bound to be pro-Jeanneau, it's good to remind ourselves that there are some good experiences out there.

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It was actually taken from the Jeanneau OWNER'S site , not the factory site so not a piece put in by the marketing men but a write up by a satisfied new owner. Not many people will do an 8,000 mile delivery trip with their brand new boat straight out of the factory!

In the interest of accuracy too, despite the name the SO 40 is actually only 38'6" LOA.

I don't really understand your comment on the 200lts/200kg of fuel in cans they put in the cockpit lockers. The standard fuel tank is not huge and ours is similarly sized at about 150lt, enough for over 60hrs motoring at 6kts in our case. Admittedly more might be nice but the limitation in our case is where the tank is sited (under the chart table) rather than because of any weight worries.

When we were looking at boats I was amazed at how some of the hardy faithful 'names' were lacking in cockpit locker space. We were moving up from a Westerly 33 Ketch with a centre cockpit and gi-normous cockpit lockers. The potential boats we initially looked at (Moody 40+s, HRs, Westerly Oceanlords, Sadler Starlight 39s to name just a few) were surprisingly lacking in cockpit locker space, lots of which was lost to walk-thru access to stern cabins. The SO 40 in the article apparently had space for 200lts in cans so at least has a bit of room.

The abilty to carry weight in light versus heavy boats was discussed in an interesting article in PBO last year by Andrew Simpson, part editor, part surveyor as well as yacht and multihull designer and builder. All is not as simple as it seems if I recall the article correctly and modern shapes CAN carry weight well, they do so without sinking as deep as older designs for the same amount of added weight. OK so the the inertia factor is there in that acceleration will suffer but the overall performance is not screwed as much as might be expected and less so than it would be on narrower heavyweights with wineglass sections.

As a matter of interest, what is your boat? I don't know why but suspect maybe even steel?
 
My problem with this amount of weight in the cockpit ..... the equivalent of 3 good sized men ...... is that it will :

1 produce a tendancy for the boat to broach on a downwind ocean passage, not only from the problem of trim but the added inertia.
2 make the autopilot work hard leading to wear in the steering system
3 put extra strain on the boats structure .... although if the boat is built properly this shouldn't be of too much concern.
4 the extra displacement ..... an addition to all the passage stores included ..... it will make the boat harder to drive and hence increase the rig loads and increase the loads in the hull structure too.

I'm a little surprised that your boat will do 60 hrs on 150 ltrs at 6kts. What is your boat and what is the displacement? Under what sort of conditions is this achievable? This is important because some boats find it very difficult to motor into weather .... and the fuel consumption naturally increases. Sometimes the engines are so undersized that they can't push the boat into a good force 5 .... with the associated waves as well. Of course motoring in dead calm should be no problem.

My boat is a GRP Cal 36 (Cruising) ...... designed by Bill Lapworth in the USA ...... She has a longish fin keel with a spade rudder. 35' 6" LOA, 10'6" beam, 6.5 tonnes ish displacement. She's a little like a Nic 35 .... but only a little /forums/images/graemlins/ooo.gif.

She was rebuilt by me in 2000 - 2001 using modern materials .... About the only thing original is the hull and deck moulding which is thick .... 13mm + on the bilge .... and using woven rovings rather that chopped strand. She makes a very, very, good ocean passager .... sails extremely well .... has a 48 hp diesel ..... 80 gal fuel in a tank in the bilge and 2 x 40 gal fresh water tanks.

Unfortunately she's been so badly damaged by a boatyard in the Caribbean that I don't think she'll ever be sound enough to cross another ocean. /forums/images/graemlins/frown.gif

You will probably right me off as a traditionalist. I'm not. I even like catamarans ...... like the Outremers. But I wouldn't choose to invest in a yacht to cross-oceans where I can't see the structural joints, there's no deep bilge to keep the bilge water under control, there's too little water and fuel storage to require jerry-cans either on deck or in lockers (you will find many modern yachts storing their extra water and fuel on deck ..... and that is plain dangerous in a blow: stanchions break, and crew get wiped out as the 25kg missiles head aft).

Overall ..... for a long distance cruising boat, for me it MUST be able to sail well and safely with cruising stores on board.

I missed Andrew Simpson's article as I'm in the Caribbean. I'd like to read it. Have you got a reference?
 
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I'm a little surprised that your boat will do 60 hrs on 150 ltrs at 6kts. What is your boat and what is the displacement? Under what sort of conditions is this achievable? This is important because some boats find it very difficult to motor into weather .... and the fuel consumption naturally increases. Sometimes the engines are so undersized that they can't push the boat into a good force 5 .... with the associated waves as well. Of course motoring in dead calm should be no problem.

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We have a 1988 Jeanneau Sun Legende 41 designed by American Doug Peterson, quoted design displacement around 8,000ks but well over 9,000 in the slings. We have a Yanmar 44hp with a Brunton 3 bladed self pitching/feathering prop and use 0.53gph (imperial gallons, not short measure US ones!) at 2,000rpm (max is 3,600) which in a flat calm gives up 6.5kts. We have no need to motor if there is wind! We would be making 7kts upwind at 28 degs apparent wind angle in F4 upwards and around 8.5kts if eased off - why would we need to motor?

We carry 360lts (about 80 galls) of water in 3 tanks (standard), plus another 12 galls in the calorifier.

Bilge water? What is that! Our bilges are dusty or there is a full enquiry!

We have a draught of around 6'10" (2.08m) with a longish fin keel (we can dry out alongside a quay) and a spade rudder with a short skeg, beam is 12'11".

See pics below - note the antifoul is taken well above the true waterline.

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The only potential weakness I think (and I'm talking about nearly all AWB brands here) is the unsupported spade rudder. If I were thinking about long term long distance sailing, I would probably prefer some kind of support.


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I have grave doubts as well about spade rudders.. I think they are fine for 'local' sailing and certainly seem to make going astern really easy but they are very vulnerable... The skeg on my old moody had certainly hit one or two things over the years and nights and thousands of miles... There is debris floating about and at night or heavy weather we don't see it... Makes a Spade rudder very liable to damage even if the design for 'normal' wear and tear is excellent.

In all honesty within a couple of hundred miles of the shore it does not matter too much if the rudder breaks - you will get rescued - there do seem to be a lot of ARC boats floating around abandoned in the Atlantic with broken rudders each year... Are they all spade design???
 
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I have grave doubts as well about spade rudders.. I think they are fine for 'local' sailing

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On balance (excuse the pun) I think you are right but it is not a structural win-win choice. Take the classic wooden 50ft yacht that triggered a lifeboat callout off Yarmouth over the weekend due to steering failure. The rudder was probably a highly inefficient thing that put massive strains on the steering control mechanism. Ok so base the rudder design around a partial skeg and still benefit from a balanced rudder? Trouble is now the skeg is a relatively small appendage to the hull and a new weak point.
 
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I have grave doubts as well about spade rudders.. I think they are fine for 'local' sailing and certainly seem to make going astern really easy but they are very vulnerable... The skeg on my old moody had certainly hit one or two things over the years and nights and thousands of miles... There is debris floating about and at night or heavy weather we don't see it... Makes a Spade rudder very liable to damage even if the design for 'normal' wear and tear is excellent.

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Sometimes what seems a better option isn't. I would have agreed with your thinking but then remember there was a Moody (40???) that sank off Oz many years ago who was advertising in UK mags for other Moody owners who had experienced skegs cracking, apparently his skeg broke adrift leaving a big hole in the hull. Also didn't Andrew Bray's (one time YM/YW Editor) Sadler 34 have to retire from an ARC crossing with a leak from a cracked skeg? Maybe the proviso should be that the skeg is a solid moulding added on to the outside of the hull rather than simply moulded into the hull and hollow.
 
Yes - I remember the small ad about the Moody appearing every month in YM asking if others had had similar problems. I never did find out how it was resolved.

Spade rudders have been around a long time and have appeared on many ocean crossers. Many of the early Van de Stadt designs had spades - the Pioneer 30 comes to mind immediately. 'Aziz' is a notable example of that class.

My first boat was a Van de Stadt design with a short fin keel and skeg hung rudder. Beautifully moulded by Tyler but...you could grip the bottom of the skeg and flex it fairly easily. Skegs are all very well but they need to be bomb proof if they're to stand up to hitting something solid at any speed. I suspect that many of them aren't.
 
Robin said ".....We have no need to motor if there is wind! We would be making 7kts upwind at 28 degs apparent wind angle in F4 upwards and around 8.5kts if eased off - why would we need to motor?"

This sounds like flat seas sailing ...... Where do you sail? How about the performance in open water with a fully developed F5 sea? You must surely have to de-power your rig and ease of the wind ... say 7 deg at least? What would your speed be then ... and how much does she slam?

It sounds as if your boat is well equiped and shouldn't have to worry about being under-powered, especially with a three bladed prop.

I'd prefer to sail whenever possible, but there are times when motorsailing into wind is the only practicle answer to beating the tide, weather, and the dusk.

Sometimes even tacking into a 2 knot current won't get you very far, especially in a fully developed sea. Try beating from Margarita to Granada ..... 2kt ocean current (doesn't change much with the tide).

There has also been times such as in TS Delta that my engine saved my boat when my anchors needed to be repositioned in 65 kts. /forums/images/graemlins/ooo.gif
 
Spade rudders are fine if they are designed and maintained properly ....... like everything else! /forums/images/graemlins/ooo.gif

Some spades are designed to have sacrificial bottoms to protect the rest of the steering gear. If these work properly ..... and I've seen a few broken due to groundings .... there should still be enough rudder to get home on.

As for ARC abondoned boats ..... perhaps the RYA should start teaching people how to set up their rigs and cobble together dury rudders to get to a safe haven as part of the yachtmaster courses. A good skipper should always be able to think on his feet ..... rather that pushing the EPIRB button. /forums/images/graemlins/ooo.gif
 
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