15M Catamaran Capsize off Portugal

[fxykty]

Originally Posted by At Peace

Just a thought on not seeing the port dagger board. Performance cats often have the windward board pulled up into the hull to reduce drag.

Not correct for non foiling daggerboards: the leeward one is lifted. This prevents tripping over the leeward board in a big gust or big wave. Typically both boards are up for anything downwind of a close reach. Both boards can be down in light and medium conditions upwind to minimise leeway.

You are correct if you meant daggerboards with a lifting foil - in that case the leeward board is left down to lift that hull. The windward board down would lift the windward hull, which is the opposite of what you want. A local 60 foot performance cat says they get up to 4 metric tons of lift from their foil, which for an 8 metric ton boat is huge. Not sure how these work in big seas, but that same boat also told me that they make passages with 3 people on each watch hand holding the helm, mainsheet, traveller and jib sheet - they’re twitchy and not for casual cruising.

[leftbrainstuff]

Speed has zero correlation to the probability of hitting something in the ocean. Area of water traversed would, which is independent of speed.

Originally Posted by smj

Im sure the higher the speed the more of a chance of pitchpoling you have if you hit a submerged object. Also the higher the speed the less time you spend on passage so less of a chance of finding the submerged object?

[jtsailjt]

Originally Posted by leftbrainstuff

Speed has zero correlation to the probability of hitting something in the ocean. Area of water traversed would, which is independent of speed.

But he said the greater the speed the better the chance of pitchpoling IF you hit something. He didn’t say that increased speed had any correlation to the probability of hitting something.

However, during good visibility conditions I think that higher speed does increase your chance of hitting something in the ocean because at greater speed you have less of a chance to visibly pick up something that’s barely out of the water. At slow speeds, once the object is in visible range you will have more time before you get to it so more chance of noticing it so you can avoid it. In dark night or poor visibility conditions you’re right that speed doesn’t matter.

[Cat_sailor]

Hey Guys! my first comment in this forum.

This is a very interesting discussion, does anybody have some scientific studies backing up and explaining why catamarans capsize?

I find it hard to find some good reliable info that isn't just opinions!

Cheers!

[Training Wheels]

Too much wind with too much sail.

[fxykty]

Originally Posted by Training Wheels

Too much wind with too much sail.

They were on a reach, so it could have been a quick slowdown (object and/or wave) that slows the boat and quickly increases the apparent wind. That doesn’t mean they had too much sail up, just bad luck.

Though typically cruising on a performance boat like that you can really decrease the sail area and still keep a decent average speed, with double or triple of the standard capsize resistance.

[Cat_sailor]

https://www.catamaranfreedom.com/why...for-beginners/

What do you guys think about this approach to explaining it?

[fxykty]

Originally Posted by Cat_sailor

https://www.catamaranfreedom.com/why...for-beginners/

What do you guys think about this approach to explaining it?

Reasonable, but still based on a bunch of anecdotes as he didn’t show any other references.

But from the point of view of frequency of capsizes, the insurance statistics should tell you all that is needed. That would be a valuable analysis. Extrapolating based on the rates they charge, there doesn’t seem any difference for catamarans versus equivalent size/value monohulls as far as I can see.

[Palarran]

Originally Posted by Old fella

Yeah I know what you mean, I’m fizzing at the bung watching these races. I understand though even if the kiwis win the cup, it looks like they will take the next cup off shore. The good thing about that is it could create more challenges, although I would prefer to see it stay here.

Congratulations Old fella. That was super enjoyable and I'm super happy to have called it totally wrong. I do have to admit, there was a desire to root for the Italians. I just like underdogs in sports.

fizzing at the bung - hadn't heard that before - but I like it !! ;-) Probably should look up exactly what it means before putting it into my general vocab just in case it doesn't mean what I think it does.

[Cat_sailor]

Originally Posted by fxykty

Reasonable, but still based on a bunch of anecdotes as he didn’t show any other references.

But from the point of view of frequency of capsizes, the insurance statistics should tell you all that is needed. That would be a valuable analysis. Extrapolating based on the rates they charge, there doesn’t seem any difference for catamarans versus equivalent size/value monohulls as far as I can see.

I read the scientific paper and i tried looking for another study that is quoted inside but couldn't find it. And surely there should be more studies like this?

[Cat_sailor]

Originally Posted by fxykty

Reasonable, but still based on a bunch of anecdotes as he didn’t show any other references.

But from the point of view of frequency of capsizes, the insurance statistics should tell you all that is needed. That would be a valuable analysis. Extrapolating based on the rates they charge, there doesn’t seem any difference for catamarans versus equivalent size/value monohulls as far as I can see.

It is also based on other factors than capsize i would assume, which makes that type of comparison maybe too inexact.?

[Tupaia]

Originally Posted by Cat_sailor

I read the scientific paper and i tried looking for another study that is quoted inside but couldn't find it. And surely there should be more studies like this?

All you need to know.



https://shuttleworthdesign.com/NESTalk.html

[Cat_sailor]

Originally Posted by Tupaia

All you need to know.



https://shuttleworthdesign.com/NESTalk.html

Nice resource! Although a lame on the conclusions.!

[smj]

Originally Posted by Cat_sailor

Nice resource! Although a lame on the conclusions.!

Why was the conclusion lame?

[fxykty]

Originally Posted by Tupaia

All you need to know.



https://shuttleworthdesign.com/NESTalk.html

Unfortunately the analysis is very old. All catamarans (other than Wharrams and narrow-beamed cats like Prouts and Geminis) are type 6s now, so comparisons against the older types are not relevant when trying to compare the seaworthiness factors of modern (last 30 years) cats.

The lame comment could be about the recommendation for storm handling - laying ahull.