Cats rarely flip ... Irma

[admiralslater]

I think it might be interesting to try and determine if there are any particular traits among the boats that did and did not flip. For instance boats with higher bridge deck clearance quit often have less solid bridge deck but they may tend to be lighter. I would think powercats would fare better . It is all speculation as I believe 200 mph will take out just about anything. Does anyone know how big the waves got inside that big moorings base . Also and I say this with out prejudice!I wonder how far over a bare poles mono would lay and would it be able to stay water tight for long enough to survive. The economies of these small countries are going to take a beating because of this

[Snowpetrel]

Originally Posted by donradcliffe

If I was head a school of naval architecture specializing in catamarans, I would send teams down to the hardest hit areas immediately to gather as much data as I could. There are standardized calculations for transverse and longitudinal bare poles velocity for catamarans--the theoretical wind speed at which the a cat will flip with no sails up. By studying the designs and the mooring arrangements of the cats which flipped and the ones which did not flip, the school could validate or improve these calculations.

For instance, one of the pieces of data which could come pretty easily is whether any power cats flipped. Its pretty easy to calculate the bare poles velocity with and without a mast up. If the BPV is 50 knots higher with the mast down, I could see insurance companies demanding that masts be removed before a major storm.

It's an interesting topic and a potential weakness of cats. One flipped after dragging its mooring in Tasmania during the passage of a strong cold front. Maybe 80 knots or so, so well inside the normal range of gust windspeeds that may be encountered. Possibly the capsize was assisted by the weight of the mooring hanging off the bow.

It would be nice to have more info about the windspeeds and apparent wind angles where this is a possibility for different cat designs. Is water ballast or partly flooding compartments a useful option for extreme conditions?

[mikedefieslife]

It does look shocking, but it's pretty irrelevant to sailing. Though I wonder just how fast you could go in 200mph winds.

Curious how many monos flipped. I've only seen two with masts in all the images I've seen. Either they were removed on purpose, removed by the wind, or turn off after a tumble.

I think the moral of the story is stay the f away from hurricanes, and cyclones.

On a more upbeat note. Used spares in that region are going cheap.

[maxingout]

Seeing flipped catamarans in that much wind does not surprise me. A catamaran becomes a tumble weed in 185 mph of wind.

That's why there are places like Trinidad, New Zealand, and Brisbane that you go to during hurricane/cyclone season.

During our eleven year circumnavigation, I saw winds to fifty knots on only three occasions. The reason is simple. When it was hurricane/cyclone season, we left the hurricane/cyclone zones and sailed out of harms way. No rocket science here.

I understand that a charter operation like Moorings cannot move all their boats to Trinidad on short notice. What I don't understand is why a person would remain in a hurricane zone when it is hurricane season and there is a hurricane heading directly for you. You have enough warning to get out of harms way by sailing south for a couple of days.

A reasonable approach would to be spend hurricane season in Grenada, and if a hurricane is heading your way, simply do an overnight sail to Trinidad.

I never worried about my catamaran flipping from a hurricane because I did not cruise in hurricane zones during hurricane season. Seeing flipped catamarans from 185 mph winds is sad, but it's not the sort of thing that I worry about. The first rule of cruising is that when it's hurricane season, you get out of Dodge.

[john61ct]

I lived on Tortola, sailed with many liveaboard cruisers, and yes most headed south and/or west for the season, long before any specific storm came along.

But 95% of the boats there are charters or the owner flies in for short holidays and just pays her insurance.

Plenty are so wealthy, losing their iPhone would bother them more, have a staff to take care of such inconveniences.

Yes it hurts us to see the wreckages, but let's consider the poor locals whose whole lives are wiped out.

[GordMay]

Greetings and welcome aboard the CF, Binkbink, & Brent.

[Red Herring]

Originally Posted by Cotemar

With a Hurricane EYE wall and a recorded 206 MPH of wind, EVERYTHING becomes flying debris.
.
.

https://www.youtube.com/watch?v=IYbbn71h_bc

[NoahTreat]

Ron white gets it.

Something no one has mentions about those cats that flipped is storm surge. Wave breaking at the right time with a little wind would flipped those cats easily. Or the storm surge packs all those boat in the corner on top of each other then the wind comes. It's not just the wind you got to factor in storm surge.

Also. I bet most of the monos were upside down at one point.

[Red Herring]

Originally Posted by NoahTreat

Ron white gets it.

Something no one has mentions about those cats that flipped is storm surge. Wave breaking at the right time with a little wind would flipped those cats easily. Or the storm surge packs all those boat in the corner on top of each other then the wind comes. It's not just the wind you got to factor in storm surge.

Also. I bet most of the monos were upside down at one point.

Ya. Ironically, as I was describing this thread to my wife this morning, she asked if anyone had mentioned the storm surge as a contributing factor... Go wifey (and Noah)!

[danielamartindm]

Originally Posted by barrymac

https://twitter.com/saara_leon/statu...00631209906176

How many upside down cats can you count?!

Scrunch a lot of rectangular vessels together, and you find it surprising that more cats flipped over than narrow, banana-shaped monos? Really? Who buys a cat for this mission statement?

[sailingharry]

So, I'm getting close to moving from a monohull to a cat, and saw those pictures. Came here to ask a question -- and see it's being discussed!

I'm not about to ridicule any kind of boat, or any preparations. That was some serious weather. But, it does provide pause for thought an reflection on what can be learned.

Putting aside 180 kt winds, what can we apply? Is that enough wind to literally pick up a boat and flip it? How much less than 180kt can do it? How much sea can impact it? If you are out there, how do you respond?

Earlier this summer, in my Sabre 34, I was out on the Chesapeake Bay and saw thunderstorms coming (two days in a row). Took down all sails, pointed into the wind, and motored slowly, waiting for it to pass. But we saw winds close to 50kts, and 70+ is not unheard of in our afternoon thunderstorms. In a cat, would that be the wrong answer? Can 70 or 80 under bare poles cause it to flip, especially with a good sea going? Is beam-to safer, or less safe? Run before it?

Like I said, does this lend itself to some practical at-sea lessons learned, for realistic conditions that are admittedly severe, but not Irma-severe?

[NoahTreat]

Only time I've heard of or seen a cat flip without the sails up, is during a major hurricane. Doesn't mean it hasn't happen, but I don't think it happens enough to dissuade you from buying one.

[Jim Cate]

Originally Posted by NoahTreat

Ron white gets it.

Something no one has mentions about those cats that flipped is storm surge. Wave breaking at the right time with a little wind would flipped those cats easily. Or the storm surge packs all those boat in the corner on top of each other then the wind comes. It's not just the wind you got to factor in storm surge.

Also. I bet most of the monos were upside down at one point.

Not so sure about the above... in Paraquita (sp?) bay the storm surge would not have caused breaking waves, but rather a gradual increase in depth. The shallow water and very limited fetch kinda rule out seas large enough to capsize a big cat. The pileup of boats could have mechanically tilted a cat up to the point where the wind got under the bridge deck and encouraged capsize just as you proposed, but I reckon they were driven into the corner by wind, not surge.

As to monohulls, I doubt if any ballasted mono was ever upside down in there. Wind alone won't roll such a vessel... lay her flat with the mast in the water, sure, but there is little to drive her further, and the righting moment is quite high at that heel angle. Again, it takes large breaking waves to invert a ballasted monohull.

Jim

[NoahTreat]

Originally Posted by Jim Cate

Again, it takes large breaking waves to invert a ballasted monohull.

Jim

Jim. With all due respect, I think you might be underestimating the power of this storm.

[newhaul]

Originally Posted by NoahTreat

Jim. With all due respect, I think you might be underestimating the power of this storm.

Actually I would gurantee all of my monohull sailboats would have weatherd this storm quite well in that bay if not hinderd by other vessels that were not adiquately secured
Anchor by the bow and allowed adiquate swing room . ( islander bahama 24, columbia defender 29, and spencer s42. All heavily ballasted full keel with cutaway forefoot boats ( the islander and columbia are morc boats)