I watched a guy nearly capsize right in front of us

[Training Wheels]

Perhaps, but they are only cats I know of that are lashed together.

[KJThomas]

Originally Posted by earthbm

To clarify, the death zone I was referring to is when you are reaching at about 60 AWA, canvassed at the limit, and a gust hits. Then you are at a local minimum for the heeling moment and any heading change makes it worse:

1. If you bear off the mainsail gets more perpendicular to the wind

2. If you head up into the wind your AWS increases and the centrifugal force adds to the heeling.

(FWIW my preferred solution is to ease the main and head up, but sometimes there is no time and I bear off because it temporarily feels better due to lower AWS).

I have no idea if my “swell moving from under the windward hull” theory is correct. Because OP said there was a 10 degree heading change as it happened I suspect it may have been a death zone situation as described above and the heeling was real.

As to the swell pushing the windward hull over, this is mythical southern ocean or “rogue wave” kind of stuff... I don’t know. Just don’t have the lee board down I guess. And always chuck the first shot of rhum overboard to appease Neptune...

Nearly always better to bear away momentarily, as you let the sail out. Centrifugal force as you head up makes things worse.

[catsketcher]

Originally Posted by KJThomas

Nearly always better to bear away momentarily, as you let the sail out. Centrifugal force as you head up makes things worse.

Actually, sorry to be a killjoy, but this is not correct for the type of boats we usually talk about here and for most flat cat sailing. When beating upwind it is better to head up and feather the rig to depower. When deep downwind it is better to bear away. If you bear away when easing sheet when going upwind, you just power up the rig again. So be really quick on dumping sheet if need be and head up if close to the wind already.

The death zone referred to earlier in the thread is somewhere around a close reach. At this point of sail you need to make a large course change up or down to get to safety. Hence - zone of death as either choice is a long way to safety. All high powered boats - mono or multi have this issue.

I once had the good fortune to sail on an ORMA 60 tri for a few hundred miles. Sean Langman helmed her to windward in 20 knots true and it was very skilful and taxing as well. He had the main hull flying much of the time and feathered the boat up in the gusts to keep her just skipping along the wavetops - hour after hour. Up to bleed off power, bear away a few degrees to crank her up again. One of the best sails of my life but he was quick on the helm and always watchful of every gust.

Centrifugal force on a large cat at low angles of heel produces very little overturning moment The rigs are low and light compared to the rest of the boat. On small off the beach cats such as A class with very tall rigs this could be an issue but with heavy large cats with relatively low rigs the inertia of a rig is very low compared to the stability of the boat. It was a problem with C class cats in the early days, but their rigs weighed a very significant fraction of their total weight. On my 11.6m x 7m cat the mast (about 14.1m) weighs less than 3% of the total displacement. On an A class cat 5.5m x 2.3m the mast is about 9 metres long and about 9kg which is about 12 % of the boats displacement (but you need to include crew) but it is much higher proportionally, especially when you include the height in stability calcs. So an A class or Nacra could have centrifugal issues arising from the rig.

To test the centifugal idea you can round up quickly in a big blow when totally flat or heeled, Laser, skiff or beach cat - it makes little difference. If the rig inertia is the problem then heel angle would not make much difference. But when flat you can round up quite safely and easily. Heading up is not the problem, doing it too late - when heeled greatly is. So get active on the helm when sailing on the edge and get the boat up or down quickly and when at low angles of heel.

Once heeled things can change as the weight of the suspended hull is significant. Beach cats especially have this issue as the crew weight is suspended highest on the wire, whereas the cruising cat still has its CG in the middle. I would prefer to stay flat and use quick helm movements either up or down to stop the hull from flying high rather than bear away every time which will cause issues when flat going upwind because bearing away may help when the hull is high when sailing deep.

[malbert73]

Originally Posted by Factor

Yeah - nah. For all the reasons above, Hard to capsize a decent multi, easy to flip it back

Not a full out cruising multi right? I’d say hard to flip and hard to right...

[KJThomas]

Originally Posted by catsketcher

Actually, sorry to be a killjoy, but this is not correct for the type of boats we usually talk about here and for most flat cat sailing. When beating upwind it is better to head up and feather the rig to depower. When deep downwind it is better to bear away. If you bear away when easing sheet when going upwind, you just power up the rig again. So be really quick on dumping sheet if need be and head up if close to the wind already.

The death zone referred to earlier in the thread is somewhere around a close reach. At this point of sail you need to make a large course change up or down to get to safety. Hence - zone of death as either choice is a long way to safety. All high powered boats - mono or multi have this issue.

I once had the good fortune to sail on an ORMA 60 tri for a few hundred miles. Sean Langman helmed her to windward in 20 knots true and it was very skilful and taxing as well. He had the main hull flying much of the time and feathered the boat up in the gusts to keep her just skipping along the wavetops - hour after hour. Up to bleed off power, bear away a few degrees to crank her up again. One of the best sails of my life but he was quick on the helm and always watchful of every gust.

Centrifugal force on a large cat at low angles of heel produces very little overturning moment The rigs are low and light compared to the rest of the boat. On small off the beach cats such as A class with very tall rigs this could be an issue but with heavy large cats with relatively low rigs the inertia of a rig is very low compared to the stability of the boat. It was a problem with C class cats in the early days, but their rigs weighed a very significant fraction of their total weight. On my 11.6m x 7m cat the mast (about 14.1m) weighs less than 3% of the total displacement. On an A class cat 5.5m x 2.3m the mast is about 9 metres long and about 9kg which is about 12 % of the boats displacement (but you need to include crew) but it is much higher proportionally, especially when you include the height in stability calcs. So an A class or Nacra could have centrifugal issues arising from the rig.

To test the centifugal idea you can round up quickly in a big blow when totally flat or heeled, Laser, skiff or beach cat - it makes little difference. If the rig inertia is the problem then heel angle would not make much difference. But when flat you can round up quite safely and easily. Heading up is not the problem, doing it too late - when heeled greatly is. So get active on the helm when sailing on the edge and get the boat up or down quickly and when at low angles of heel.

Once heeled things can change as the weight of the suspended hull is significant. Beach cats especially have this issue as the crew weight is suspended highest on the wire, whereas the cruising cat still has its CG in the middle. I would prefer to stay flat and use quick helm movements either up or down to stop the hull from flying high rather than bear away every time which will cause issues when flat going upwind because bearing away may help when the hull is high when sailing deep.

I was answering a comment about when you are around 60° off the wind. In that case it is better to bear away. In a keel boat on the wind you round up. In a surf cat I've found it is still better to bear away, briefly.

[thinwater]

Originally Posted by Svan

Swell against tide produces elephants, steep slab sided waves. Beam on waves are NEVER FUN in a cat from powerboat swell on up. I imagine the other skipper puckered a bit there and learned to quarter the waves after that. And took some sail down.

I don’t think any other PDQ owner wants to spend any time on one hull. I teach the deck crew about the line to release when things start to go upside down shaped.

It can go so wrong so fast
https://www.reddit.com/r/yesyesyesye...oiling_mayhem/

For fun. I've sailed cats a long time and this was carefully controlled. After 10 seconds or so I feathered a little and put it back in the water. I just wanted to see how it would handle. In fact, cruising cats don't really go faster when pressed that hard to windward, since the keels generally become overpowered.



But ordinarily you never let it get very light. The art of fast sailing in a performance cruising cat is correcting preemptively so that big corrections are never required. That is faster and much safer.


If you never tickle her tail in controlled conditions, you'll end up learning about her performance envelope in a storm. Those are the ones we read about in the papers.

[Factor]

Originally Posted by malbert73

Not a full out cruising multi right? I’d say hard to flip and hard to right...

And your experience is?

[malbert73]

Originally Posted by Factor

And your experience is?

None except for internet showing several wrecked multis towed or left floating upside down. If easy to right why wouldn’t it be done?

Since your comment to me drips with vast experience with capsized large cruising multis that were easily righted, feel free to educate me with some real world examples. I’m a quick learner [emoji3]

[Cadence]

Originally Posted by malbert73

None except for internet showing several wrecked multis towed or left floating upside down. If easy to right why wouldn’t it be done?

Since your comment to me drips with vast experience with capsized large cruising multis that were easily righted, feel free to educate me with some real world examples. I’m a quick learner [emoji3]

I believe you have it correct. Hobies can be righted all day long. As I recall that high dollar Gunboat was towed in upside down and it wasn't even a heavy boat compared to a cruising cat.
My concern would be pitchpoling not flipping one.

[atlroofman]

Originally Posted by Dave_S

Just an observation, no comment on type of boat.

We were beating up wind, 25kn TWS, he was comming up behind us in a big cruising cat and lifted the hull often, occasionally it would hang up for 3 or 4 seconds then drop back down. There was wind against tide and the steep swell up to about 2.5m most around 2m.

We rounded a mark which took us off the wind about 10deg and bought the swell around to more side on. It lifted the windward hull like it did before then suddenly it shot up further to about 40° hung there for a moment like it was balancing on the edge and fell back down.

It was so fast, if the sheet is on a winch you would not have a hope of doing anything about it and I doubt the helm would shift the dynamics of the boat in time. The only chance you might have is if you were holding the sheet with a couple of wraps on the winch and just let it go.

I guess there are all types fast and slow but it was a real eye openner to see what might have happened.

Holding the sheet or traveler in your hand ready to release would be the only semi safe way to do it.
But if you want thrills like that get a beach cat, condo cats are not made to be righted again like there beach cat little brothers.

[ol1970]

We just got back from 2 week sailing trip to French Polynesia and we were out in similar to probably a little worse conditions the day we sailed from Tahaa to Bora Bora. The pass from Tahaa put us on a dead downwind sail if we took the most direct route, but it is not a far sail and we had the wind and waves at our back so we took our time and tacked a few times...it was a glorious sail for us. We did see a few large catamarans beating into the wind. A 55' Catana, 62' Lagoon, 44' FP, and a 46' Leopard...and all of them were really getting beat up. They were all motoring, but the waves they were taking on had them rocking back and forth and both hulls visible as they would crest over the wave. I could absolutely see how one of these could get a little squirrely with full sail up in these conditions. The day we sailed from Raiatea to Huahine we were the only boat out there and with 3M waves on our bow nearly the entire way...waves are hard to judge, but we had a couple that were breaking that I'd estimate just shy of 5M. First time I've ever really been intimidated by the size of waves...but damn what a sense of accomplishment my wife and I felt after we finished the crossing! If we were in a Catamaran we would have turned around...this trip we chartered a 44' mono.

[earthbm]

Originally Posted by atlroofman

Holding the sheet or traveler in your hand ready to release would be the only semi safe way to do it.

Yep.

If it’s a cruising cat with a straight traveler then the main sheet (traveler won’t travel far as the main sheet will bind it). If a racing cat with a curved traveler then the traveler (could lose the mast by letting the main sheet go in some rigs)

[Tupaia]

Originally Posted by earthbm

Yep.

If it’s a cruising cat with a straight traveler then the main sheet (traveler won’t travel far as the main sheet will bind it).

This is only a problem if the mainsheet is vertical when on the centre-line. If it is angled aft the traveller will dump easily.

[Factor]

Originally Posted by malbert73

None except for internet showing several wrecked multis towed or left floating upside down. If easy to right why wouldn’t it be done?

Since your comment to me drips with vast experience with capsized large cruising multis that were easily righted, feel free to educate me with some real world examples. I’m a quick learner [emoji3]

Lack of knowledge, a bit like the internet, salvage operator or similar paid to recover so they do, Many times I have advised folk on how to tow over a boat and their operator refused. Didnt understand the principle, didnt want to learn. It takes surprisingly little force to tow it back over.

[madprops]

Originally Posted by Factor

Lack of knowledge, a bit like the internet, salvage operator or similar paid to recover so they do, Many times I have advised folk on how to tow over a boat and their operator refused. Didnt understand the principle, didnt want to learn. It takes surprisingly little force to tow it back over.

Would you mind telling me how? Feel free to PM me if you want