Capsizing on mooring

[sparau]

Used Snell Easy 37 Catamaran for Sale | Yachts For Sale | Yachthub

Does anyone know how this occurred or can anyone please explain how a cat can capsize on a mooring?

Even as a lightship wouldn't it take an absolute gale (i guess 100-150k) to flip one considering on a mooring it wouldn't have much in the way of wave to lift a hull and get some wind under it?

[ReMetau]

We had a friend whose trimaran was capsized in Boot Key harbor on a mooring ball due to a micro-burst storm.

[44'cruisingcat]

Maybe they had an absolute gale? For instance, if a waterspout can lift water, it could also lift something that floats on water.

[sparau]

I can imagine it could happen a lot easier on a racy tri where 1 hull is always flying, I'm guessing it wasn't a searunner.

Likewise this boat is would be fairly heavy, epoxy ply construction cruiser, although it would have a fair amount of windage.

[sparau]

Originally Posted by 44'cruisingcat

Maybe they had an absolute gale? For instance, if a waterspout can lift water, it could also lift something that floats on water.

Yep, I suppose it is a useful reminder of the old adage "**** happens".

I hadn't given a lot of thought to capsizing on a mooring or at anchor though

[Jimbo485]

There was a tornado / water spout down there a few months ago. Ask if that was the one that caused the capsize.

[Cheechako]

Micro burst? Yesterday up here in the PNW where we dont have tornadoes, a neighborhood was hit tearing apart siding, roofs, sheds , large trees, and a boat on a trailer. Go figure... 45 second storm.

[Cherp]

I think that one dragged its mooring out of Kettering in the D'Entrecasteaux Channel near Hobart and was flipped out in the channel. Other boats dragged that day as well and there was considerable storm damage over southern Tasmania. Mind you, it blew to 70k for a couple of hours at Kettering, and a nearby wind station on the River Derwent gave up the ghost with a gust in the low 80s (knots that is). This little charmer was not forecast (forecast around 20-30k I think) and appears to have been a little bomb that formed on the back of a front. Don't take all this as accurate to the last knot, but it's more or less what happened.

[JPA Cate]

Slightly different story, but second hand (we were in Pt. Davey at the time). The way I heard it, the catamaran did flip at its mooring, and it was caught in a microburst. There was a "white squall" with the frontal passage, a storm cell in the front. Our friends recorded 80 knots. The wind just must have got under it and lifted/pushed it over. Very sad story.

The friends who told us were the crew aboard the Solquest, skippered by Garth Wigston, who upped anchor and went out in it to rescue the Varg. If anyone's interested in the story, it can be found in the newsletter for the wooden boat festival, good story and pix from Casi from Pt. Townsend, WA.

Ann

[Polux]

80K is a lot of wind, that cat has a considerable windage and is very light. I have heard stories of cats moving frantically on the anchorage and menacing to capsize in very high winds.
I do remember quite well a Route du Rhum were several 60ft ORMA trimarans were capsized only by the sheer force of the wind on their wing masts (no sails). The rigging and masts were modified after that.

[BigBeakie]

And don't forget that cats with sloping windows develop lift like an airfoil if they have smooth air flow over them. The amount of lift is quite amazing and I'm informed by an insurance assessor that there are numerous cases of cats flipping when on the hard from the airfoil lift they develop once the wind is strong enough.

The designs with vertical saloon windows have an advantage here in that the airflow would be disturbed in really high wind situations, so would be more stable.

I spoke to Lock Crowther many years ago about this when anchored or lying to a parachute anchor in survival conditions. He thought it was a good idea to tie a door, or anything else big and bulky (the dinghy?), against the front edge of the mast to try and disturb the airflow as much as possible. Hope I never have to contemplate this in reality!

[sparau]

Looking closer at the specs it is listed as only 4000Kg, I must admit I was expecting it to be heavier than say a Schionning of a similar length made out of composite panels… Either the listing is wrong is it is pretty lightly built?

I was going to ask why all the schionnings weren't falling over with higher bridge deck clearance but less windage and supposedly more displacement should fix that problem until 100k or so I guess

[sparau]

Originally Posted by BigBeakie

I spoke to Lock Crowther many years ago about this when anchored or lying to a parachute anchor in survival conditions. He thought it was a good idea to tie a door, or anything else big and bulky (the dinghy?), against the front edge of the mast to try and disturb the airflow as much as possible. Hope I never have to contemplate this in reality!

Gee, manhandling a dinghy into place in hairy conditions would be fun !

But what you are saying makes sense.

[Jeannius]

We were in a marina in St Maarten Lagoon during Hurricane Omar in 2008. No more than 200 yards from us, a Lagoon 410 at anchor went over during the storm. Although the main storm was generating 'just' 120 knot winds, there was complete devastation in narrow paths where there had been micro tornadoes generating wind speeds of more than 200 knots.

If you get enough wind almost ANYTHING can be picked up and turned over!

[noelex 77]

There was a cat that flipped at anchor a few years ago in Greece. A woman was trapped inside the upturned cat until a brave soul dove underneath and rescued her.

It was a short, but bad storm.

ΑνεμοÏÆ’Ï„Ï�ÏŒβιλοÏ‚ ÏÆ’Ï„ο Î’λυχÏÅ’ ΛεÏ…κάδαÏ‚ - Tornado at vlyho - YouTube