Atlantic 57 Catamaran Capsized

[admiralslater]

Brian those vids where incredible . It was interesting to see how strong the demarcation line is .In the second video the second video the school bus is blown over but the little flatbed trailer does not move.

[catsketcher]

As to windward and leeward boards - Usually the boat will tell you. It is standard practice to use both boards, usually to the same amount. Most board cats need both boards down in normal weather to get enough underwater area. If the weather gets nasty you tend to pull the leeward one up more.

What interests me about the capsize stories is the difference between cats and tris. In the 70s and 80s, before EPIRBS, capsize survivors often had to live for extended periods of time in their boats. In a tri you can chop holes in the bottom of the main hull and the boat does not settle far. The trapped air in the inverted crossbeams and floats hold them very high. John Glennie, and three others, on Rose No-elle lasted 119 days on his tri this way.

Although the Atlantic cats seem very well designed it does seem as if they missed some safety facets that could have helped - non skid and attachment points on the underwing would have made it easier for the crew. Also it seems a lesson to be learnt is that, if possible, any crew inside after the capsize should turn off all seacocks. In the 1960s Val Howells capsized a CSK design, Golden Cockerel. The pictures show her floating very high after the event with the crew seemingly lounging around on the bridgedeck. One young guy located inside after the capsize had the presence of mind to shut all the seacocks to keep the trapped air inside the hulls.

Of course then you must get out of the hulls. I don't have the cuttings any more but in the 90s a cat capsized in the Med. One crewman was outside and talked to the rest (about 3 or 4) who were inside. After a few hours they stopped talking to him through the hull and died.

So for most cats you will need to get the dinghy or liferaft onto the bridgedeck. According to the Ana video and report and this report, this is not going to be fun or comfortable. I prefer the idea of a watertight bulkhead forward - somewhere you can cut into without letting the trapped air escape - under a forward bunk would be okay. A saw or axe located within reach of the inverted bridgedeck and a sticker showing where to cut is a good idea in my book. There have been cases where people cut into the (trimaran) hulls with a belt buckle - a cheap saw is better but laminates are pretty thick on some cats.

I guess the question we should all think of is - Where would we survive whilst waiting for help?

cheers

Phil

[leftbrainstuff]

Originally Posted by SV DestinyAscen

Sounds easier to just have a salvage crew with a crane lift both hulls to water level to first drain the seawater - then lift one hull and revert. Not sure I'd want a boat if the salvage crew flips it longitudinal by pulling. It isn't a static load as it flips and lands on itself again, probably do more damage to the boat.

The loads from a longitudinal righting will probably exceed the structural capacity of the boat.

As an engineer i'd pass on that boat after this type of righting.

It also makes little sense in terms of bouyancy. Righting transversely places loads in the same axis as the standing rigging. You also gain stability from the hull remaining in the water.

Sent from my SM-N900T using Cruisers Sailing Forum mobile app

[CookiesnTequila]

Originally Posted by PhiSig1071

Yes, but the daggerboards offer significantly more lateral resistance over mini-keels. If mini-keels were as effective as boards no one would use boards, and the Atlantic would certainly not have both.

Your Catana has boards right? So which is it? Are you supposed to sail with the windward or leeward board down?

Catana does not mention using only the windward board, they state to use both boards, but only half lowered above 10 knots (which sounds very conservative to me) But I do lift the leeward board completely in heavy beam seas, for exactly that reason. But sailing the way they were, 20 - 30 knots of wind and sailing hard on the wind, is exactly what the daggerboards are there for.

[admiralslater]

Catsketcher ,both our boats are dagger board cats and each is different . On our PDQ36 when we are racing we only use the lee board and switch them at every tack. When I am cruising it we put both down until they are flush with the deck . The Outremer I am not so sure about . I think it needs both . If the weather started to get hairy or perhaps over night I would consider running with the weather board only.
I would be surprised if the Chris white did not have a hatch built into the hull already most deep sea multihulls do . When I had the 36 built the bridge deck was done in safety Orange and U bolts for clipping to where also installed . The Outremer has escape hatches ,jack lines under the bridge deck and a life raft.. the can be deployed from either side .

[CookiesnTequila]

Originally Posted by admiralslater

Catsketcher ,both our boats are dagger board cats and each is different . On our PDQ36 when we are racing we only use the lee board and switch them at every tack. When I am cruising it we put both down until they are flush with the deck . The Outremer I am not so sure about . I think it needs both . If the weather started to get hairy or perhaps over night I would consider running with the weather board only.
I would be surprised if the Chris white did not have a hatch built into the hull already most deep sea multihulls do . When I had the 36 built the bridge deck was done in safety Orange and U bolts for clipping to where also installed . The Outremer has escape hatches ,jack lines under the bridge deck and a life raft.. the can be deployed from either side .

Our Catana has the same as your Outremer, and a big red cross and strobe light built into the hull that deploys automatically if inverted (same as the lifering lights). A sober reminder every time we swim under it!

[PhiSig1071]

Originally Posted by CookiesnTequila

Catana does not mention using only the windward board, they state to use both boards, but only half lowered above 10 knots (which sounds very conservative to me) But I do lift the leeward board completely in heavy beam seas, for exactly that reason. But sailing the way they were, 20 - 30 knots of wind and sailing hard on the wind, is exactly what the daggerboards are there for.

I understand that the boards are designed for windward performance, I was under the impression that it was preferable to only use one, the windward one, especially in unsettled weather. I find it odd that the Captain specifically mentioned that he had the leeward board down. I feel like if he had both down he would have said "the boards were down 3 feet" or "both boards were down 3 feet". The way he said it makes me think he only had one down.

If it was a rogue tornado/waterspout then it's possible that board had little or no effect on the outcome. If it was a rogue wave, then it might have made a difference. But it seems like the general consensus is that it was a rogue wind phenomenon.

[belizesailor]

Originally Posted by Boatguy30

I think the slide thing is more intended when beam to large seas with reduced or no sail up. Boat is less likely to "trip" MAYBE

Prouts all have keels and are supposedly the safest cats.

Im very skeptical of this slide theory. Ive seen it discussed a few times, but have never run across a real world case.

Anyone?

[Boatguy30]

It's basically in every book about multihull design so been discussed more than a few times everywhere.

It does make sense in theory but as I say, most of the multihulls with the best safety records have keels or deep V hulls.

[Polux]

Originally Posted by Boatguy30

It's basically in every book about multihull design so been discussed more than a few times everywhere.

It does make sense in theory but as I say, most of the multihulls with the best safety records have keels or deep V hulls.

The best safety record has not to do with the keels but with the fact that normally the ones that have keels are heavy condocats while the ones without keels and daggerboards are almost always light performance cruisers.

That safety record has nothing to do with the keels but with a much bigger stability, for the same size, due to the much superior weight and also because the rigs are smaller, proportionally to the overall stability.

It is not a theory but a fact that the keel surface is detrimental for dynamic stability and it is well known that monohull centerboarders, with a worse static stability compensate that with a better dynamic stability.

On an old book by one of the best sailors from the XX century (Tabarly) that had a big experience with boats with full keel and with a much smaller keel surface (more modern racers at the time) explained the differences.





On cats, keels are also detrimental for dynamic stability since they offer a bigger surface compared with daggerboards (that can also be raised), but the huge difference in static stability of a condo cat more than compensates that handicap in dynamic stability, making it a safer cat (for the same size).

[catsketcher]

Gday Admiral

In the accounts I have read both the Atlantic boats have escape hatches. On the Anna example the crewman decided to stay inside (in the dry forward capsize area) whilst the owner was outside in the dinghy.Escape hatches can be a good idea although I have sailed a boat where one leaked profusely which could have been a real problem if not dealt with.

My point about escape hatches is that they are good but they alone will not ensure survival. With modern EPIRBS it seems like we do not have to wait like sailors of old, yet the capsize, and subsequent death of the crew, of the South African production cat (Sunsail/Moorings) shows that long term habitation is still a valuable asset. In the 80s I knew an awful lot of people who had capsized. I knew John Glennie and was in love with his tri that capsized. The owners of Twiggy, a twice capsized Crowther were family friends as was/ owner of a Crowther 10 cat that had structural issues and capsized as a result. It was actually hard to find someone who had not flipped. On the cat someone died even though they were only on the bridgedeck for a few hours. In the tri examples both crews waited for days or months reasonably safely.

To my mind there is a little bit of a blind spot when talking about capsizing. I would like everyone to consider where they would live IF they lost the EPIRB in a flip and had to wait for a few days or weeks. Trimarans will float high as a matter of course, the same cannot be said of cats and whilst some designs may be more stable all cats can be capsized. Some cats will float much higher inverted than others. It makes sense to deal with the probability, however low, and then feel more secure as a result.

[Sos]

Originally Posted by belizesailor

Im very skeptical of this slide theory. Ive seen it discussed a few times, but have never run across a real world case.

Anyone?

We were caught out on our Wharram Naria in large beam on waves and the slide slip was quite noticeable when hit by a wave. It was also possible to see the GPS course drastically change at the same time.
I was worried about the relatively deep hulls of the Narai not sliding.
The face of the waves were about 2.5 times the beam of the boat, wind about 50 knots.

[poiu]

Just wondering: this sounds to me like the capsize was caused by a tornado/waterspout. That would pose a danger no matter what you do given 100kt + wind speeds.

What are the wind stability limits of various cats on bare poles?

I think a number of cats have been flipped at anchor haven't they?

[Polux]

Originally Posted by catsketcher

Gday Admiral

In the accounts I have read both the Atlantic boats have escape hatches. On the Anna example the crewman decided to stay inside (in the dry forward capsize area) whilst the owner was outside in the dinghy.Escape hatches can be a good idea although I have sailed a boat where one leaked profusely which could have been a real problem if not dealt with.
...

Escape hatches are mandatory to have a cruising cat certified by the RCD and as manufacturers have hopes to sell some on the European market, practically all modern ones have them.

[Polux]

Originally Posted by poiu

Just wondering: this sounds to me like the capsize was caused by a tornado/waterspout. That would pose a danger no matter what you do given 100kt + wind speeds.

What are the wind stability limits of various cats on bare poles?

I think a number of cats have been flipped at anchor haven't they?

I remember those Orma 60 trimarans on a big Atlantic storm that were capsized on bare poles. They found out that they would capsize with 70k winds.

It is true that they had huge masts, were light but had also a huge stability due to a very big beam (as you know normally the trimarans have a bigger beam than cats).