Multihull RTIT capsize

I am told the boat capsized with both boards down and sailed hard on the wind. Windward hull lifted and helmsman had no rudder to steer out of it. It began heeling over like a monohull. No one on the sheets to depower. When similar cats with boards are sailed hard to windward then owners should be made aware to just deploy the windward board. If the windward hull did lift the boat is still very unlikely to capsize without a means to trip over. Cruising cats should only have low aspect ratio keels, small rigs and modest speeds to be bombproof from a capsize threat. Cats with boards and biggish rigs should not be pressed hard without an owner knowing the risks and best practices of seamanship.
 
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gemini capsize

Interesting to see this picture from another forum. This solid glass catamaran is just about floating with a load of fenders in the bows. My son struggled to hang on. If the boat was foam sandwich it would have floated high above the water upside down. It would have been safer, stronger, perform better still and more expensive. There are a huge range of catamarans. They can be built to be the safest boats on the water but others with drop keels need some knowledge to sail them safely. Geminis probably number in the 1000s and some people I hear sail them long distance across oceans with the keels a maximum of a third of the way down.
 
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The Lazy Kipper said:
I agree, it's just I thought the Gemini was more of a cruising cat than that. I never thought you could capsize one in a benign coastal F6.
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It's not really the most benign bit of coast in my experience.
Lot of tide.
Lumpy.

I'm surprised there isn't at least one water proof bulkhead in each hull.
I'm not sure I agree with the idea of lifting the leeward board entirely, I would think that gave interesting handling in choppy seas, wouldn't the windward board lose grip causing the hulls to bear off around the rudders on every wave cycle?
When going across the waves, you would have a situation that the windward dagger was generating most lateral resistance when the wave was lifting the windward hull. With the crest-trough distance being comparable to the beam of the cat, I should think that could be a recipe for capsize?
 
Unfortunately I don't have experience of handling a Gemini beam on with only the windward daggerboard down. One owner said it handled ok ..... maybe someone on here can confirm this. Waves move so quickly at sea under the boat so the hull in a trough is on a crest in an instant. A cat has enormous lateral stability. From what I read and understand - sailing cat capsizes nearly all relate to
A) going too fast downwind and pitch poling. In survival conditions you may even need to stream a warp from a bridle even with no sail up. Longitudinal stability is less than the lateral stability.
B) tripping over a daggerboard to windward. A steep wave will assist the trip but ultimately the wind is the main culprit coupled with questionable seamanship ie.pressing the boat too hard with too much daggerboard down.
 
Contributing

Gemini - LWL 32' - Beam 14' ........w/daggerboards

Lagoon 380 - LWL 36' - Beam 21.5 ...... just for an example

Gemini is a less forgiving Cat given the narrow beam, use of boards, light weight. Requires Vigilance and prompt adjustments to changing conditions + careful maneuvers if faced with higher winds and rougher seas
 
where were the crew ?

No one on the sheets to depower ! (quote )

this race was held in windy conditions , the race record was missed by just one minute !

what were the crew doing during this rough part of the passage ?

had I been skipper I would have chained a crewman to the mainsheet on standby ,

from what I gather the Gemini is a very seaworthy boat , proven by the company owner sailing one across to England from East coast USA in some fairly strong weather .
 
capsize

This is a capsize in last years round the island coincidentally the picture taken by my son. This is foam sandwich construction. I believe this capsized as it was overpressed sailing downwind just past the needles. It was a high performance boat with low aspect ratio keels. The differences between the two boats is stark.
 
The Lazy Kipper said:
I agree, it's just I thought the Gemini was more of a cruising cat than that. I never thought you could capsize one in a benign coastal F6.
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Gemini is a lightweight performance cruising cat, that very definitely has limits. It has a narrow beam by modern standards and large sail area. This plus the boards and the lightweight make it a great coastal cruising boat, but one that needs carefull looking after when on the edge of the performance envelope.
 
capsize

"Gemini is a lightweight performance cruising cat, that very definitely has limits. It has a narrow beam by modern standards and large sail area. This plus the boards and the lightweight make it a great coastal cruising boat, but one that needs carefull looking after when on the edge of the performance envelope."

Agree that it is an OK boat built to a budget. Is it really lightweight considering it is solid glass and not a foam sandwich construction?
 
victoraspey said:
This is a capsize in last years round the island coincidentally the picture taken by my son. This is foam sandwich construction. I believe this capsized as it was overpressed sailing downwind just past the needles. It was a high performance boat with low aspect ratio keels. The differences between the two boats is stark.
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I don't think you will find the buoyancy of that inverted cat was due to having foam sandwich hulls.
Much more likely to have watertight compartments, or simply small enough hatches that the hulls can invert without filling with water.
'Solid GRP' monohulls usually float inverted simply because they don't completely flood.

I think to discuss whether a Gemini counts as 'lightweight' it would make a lot more sense to find oput what it actually weighed rather than whether it is foam sandwich or not. A lightly built solid laminate might well be lighter than a heavy composite layup.
A boat with few bulkheads might be on the light side.

I suspect the Gemini capsize was partly caused by it being narrow and the length of the waves being close to twice its beam. Coupled with a course across the waves, it is easy for a catamaran to be overpowered in these circumstances.
Often with 'dinghy' cats, the tipping point is when a wave slows the boat drastically, causing an increase in apparent wind, which also move back, so that even a fully eased main will not spill wind.
A good helm who can keep the boat moving fast is an asset.
 
Weight

Agree with you that a light lay up without too many bulkheads can be lighter than a composite boat. I don't know enough about the Gemini to comment which it is. Pretty sure though there are no watertight bulkheads on the Gemini.

Actually a beam on wave induced capsize is more likely on a monohull than a cat from all I have read, seen tank tested, and experienced on power cats. The wave moves too fast under the boat to create a problem. There is enormous lateral stability even with a narrow beam. Feel more threatened generally speaking on monohulls by a purely wave induced capsize. Ie. sails down in a storm motoring across the waves.

There are a lot of power catamarans out there commercially. Can anyone find me a picture of one proven to be capsized by a wave?
 
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victoraspey said:
Agree with you that a light lay up without too many bulkheads can be lighter than a composite boat. I don't know enough about the Gemini to comment which it is. Pretty sure though there are no watertight bulkheads on the Gemini.

Actually a beam on wave induced capsize is more likely on a monohull than a cat from all I have read, seen tank tested, and experienced on power cats. The wave moves too fast under the boat to create a problem. There is enormous lateral stability even with a narrow beam. Feel more threatened generally speaking on monohulls by a purely wave induced capsize. Ie. sails down in a storm motoring across the waves.
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Probably not purely wave-induced, more a matter of wave, wind and dynamic effects stacking up?
I agree motoring across steep waves in a monohull can be worrying, but at the end of the day it is one of the cats that was upside down and not one of the much larger number of monohulls.
Hopefully it will dry out and sail again soon!
 
This is a multihull racing risk, but I doubt if this was entirely wave related; I have to assume that wind at least played a part. It looks to me that when the dragonfly went over on the sequence of photos she looked overpowered, and when out of control not depowered quickly enough. I suspect there was a good deal of power on when this cat went over. I have a 45foot cat that we sail on the Scottish islands peaks race; we have one more than once. this has included going round the Mull of Kintyre in a steady 40kts, with huge seas. A trimaran in front of us retired because of the fright he got, but we stayed out of the overfalls (they are marked on the chart) and reefed right down for the conditions. When we did the same race in a 30 foot open bridge deck racing cat, we had a knife and an axe (yes an axe) with which we could cut the mainsheet if it jammed. The philosophy of multihull racing has to be "to finish first first you must finish".

I did look at this boat at the London Boat Show and was told that it could sail quicker than an F31 trimaran (which was my previous boat). Not with a 35 foot keel it can't. The fact is that it is not an offshore design, and should be considered with that in mind.
 
Capsize

What frightens me about the Gemini is it appears to be lightly built in solid grp with no watertight bulkheads. Most multihulls float upside down ok and make good liferafts. This one apparently would have sunk like a monohull it had not been for the fenders in the bows. It ended up with its bows pointing skyward with frightening speed. My young son said it happened in seconds and he was in the cockpit with the boat on top of him. Not getting out from under the boat really quickly as he did would have caused a fatality. Had anyone been down below at the time would likely have been fatal too. Very sobering thought.
 
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