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Old 05-06-2019, 09:32   #1
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How many cats have flipped ?

Just saw a video of a rescue of a couple from an overturned Atlantic 57.
Made me think. What is the frequence of cruising catamarans flipping? Is there a common cause ? Are certian boats more prone to flip ?
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Old 05-06-2019, 09:51   #2
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Re: How many cats have flipped ?

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What is the frequence of cruising catamarans flipping?
Once per catamaran

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Is there a common cause ?
Operator error/inattentaveness

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Are certian boats more prone to flip ?
Only when handled by either an inexperienced on in inattentive sailor.
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Old 05-06-2019, 10:01   #3
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Re: How many cats have flipped ?

I don't think that statistic exists. My gut feeling is that catamarans capsize more often per cruising mile. I can't prove that though.

All one can really say is that at a 90 degree angle of inclination that a catamaran is unlikely to right itself but a monohull is likely to right itself as long as there was a minimal amount of water ingress into the cabin. Both types of vessels have very different righting moment curves. This would only apply to ocean swell that is not severe. Under severe conditions where you have swells rolling I would imagine the chance of rolling is about equal given the same angle of inclination into the swell.

I know this will stir up controversy but I think monohulls overall have a bit of an advantage in severe wind and ocean swell conditions.

On the other side of the debate, catamarans have a greater initial righting moment and less beam per hull providing a speed advantage allowing them to dodge low pressure areas more readily. If you have the ability to reduce the chance of getting into a bad situation in the first place then that is a distinct advantage.
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Old 05-06-2019, 10:05   #4
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Re: How many cats have flipped ?

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Once per catamaran

Well that made coffee shoot out my nose, so thanks for that.
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Old 05-06-2019, 10:10   #5
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Re: How many cats have flipped ?

I've seen plenty of pics of them upside down. But how common? Hard to say. I think one reason they flip is cats don't give much warning; they stand up straight and it's hard to tell what's going on.
I once accidentally got caught in temporary winds to 40 on a reach in my cat , in steep seas also. Full canvas up, you really couldn't tell it. It got me to thinking "what is the point where things quickly go upside down?" In a mono you feel the gusts and feel the heel to make decisions.
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Old 05-06-2019, 10:36   #6
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Re: How many cats have flipped ?

I once saw a device advertised that will blow the mainsheet automatically at a preset angle of inclination. That might help to reduce the capsizes.
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Old 05-06-2019, 10:39   #7
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Re: How many cats have flipped ?

Statistically you have about the same chance of flipping a cruising cat as you do sinking a cruising monohull, pick your poison.
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Old 05-06-2019, 10:56   #8
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Re: How many cats have flipped ?

I’ve wondered the same myself. In the Caribbean I see cars sailing with a full job and main when I’m at 1st reef in the main and stay sail. My sense is that there are a number of these cats being over powered but the owners/captains don’t know it.

We have a friend who will charter a cat every second year. One year he said he saw a BIG (57’?) cat leave the charter dock only to come back 2 days later with a busted mast and a dead guy.

One would think the insurance companies or large charter companies would have some stats.
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Old 05-06-2019, 11:02   #9
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Re: How many cats have flipped ?

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Iíve wondered the same myself. In the Caribbean I see cars sailing with a full job and main when Iím at 1st reef in the main and stay sail. My sense is that there are a number of these cats being over powered but the owners/captains donít know it.

We have a friend who will charter a cat every second year. One year he said he saw a BIG (57í?) cat leave the charter dock only to come back 2 days later with a busted mast and a dead guy.

One would think the insurance companies or large charter companies would have some stats.


The stat I gave above came from a Lloydís of London insurance rep.
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Old 05-06-2019, 11:11   #10
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Re: How many cats have flipped ?

There is really no such thing as a generic cat.

Light weight performance cats, especially if they are racing at the bleeding edge, are much more likely to capsize than an under canvassed condomaran that often times are motoring, and often times only doing coastal cruising.

As with a lot of things a capsize is often the result of multiple factors and not a single thing. Failure to reef early in the face of an approaching storm and broaching on the face of a wave to an awkward angle while a sudden gust from a micro burst hits and lifts the bridge deck as the dagger board gets caught can result in a capsize; but if any one of these factors is missing there may not be a capsize. On the other hand any single one could result in a capsize.

My take is many condomarans would never capsize due to their design along with how often they are overloaded. If a cat is able to fly a hull it is more likely to capsize; but that also assumes the standing rigging is capable of holding up to the loads needed to capsize the boat. There have been some lighter cats getting capsized due to a microburst getting under the bridge deck and flipping at anchor; but that is rare. In fact except for beach cats it is rare for cats to flip.

On the other hand I lost count of the number of times I flipped my Hobie.
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Old 05-06-2019, 11:15   #11
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Re: How many cats have flipped ?

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Statistically you have about the same chance of flipping a cruising cat as you do sinking a cruising monohull, pick your poison.
I was going to dispute that till I saw your later post which indicated to me you are not talking about all boats; rather only boats that are insured. I can remember a couple of times Charles and I (along with others) set up a Honda 2000 and a pump on the deck of a monohull sinking on a ball in BKH.

I imagine if Lloyds insures a boat it had a survey and was in good shape.
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Old 05-06-2019, 11:39   #12
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Re: How many cats have flipped ?

This is a well worn topic. That tends to attract trolls and passionate mono and multihull enthusiasts.
Be skeptical of those making assertions without links to credible fact bases or sources. I won’t pretend I have any of those.
The monohull missionaries will point to a number of multihull inversions and discuss the dangers of boats with stability curves that disappear as you approach 90 degrees.
Multihull advocates will acknowledge that multihulls tend to have two stable positions upright and fully inverted. They will then make the case that it’s better to up side down in or on something with positive flotation even when flooded as compared to monohulls that may be self righting but typically don’t have positive flotation when flooded (as may happen with a knock down, through hull failure, or hull breach). Its worth noting that some of the “unsinkable” multihulls have proven their ability to sink but the absence of a ballasted keel makes it easier to have a truly unsinkable boat. Many multihulls are designed (including Atlantics) to have crew living/shelter arrangements in the event of an inversion.
The multihull enthusiasts will point out that monohullls have two stable positions – on the surface when not flooded, and on the bottom when flooded. That leads to the next point – an inverted multihull is more likely to make the news get good photo coverage than the monohull on the bottom as the later is less photogenic and more likely to disappear without a follow up story from survivors.
Some of the older multihulls were more prone to capsize. In particular higher performance multis are more prone to capsize (Atlantics would fit in the higher performance bucket). The more condomaran charter boats tend to have more conservative rigs.
Most modern bridge deck catamarans sailed by competent appropriately cautious crews have a low risk of capsize (and a decent likely hood of maintaining shelter if a capsize occurs). However the combination of poor crew judgement (reef early and often) and sever/surprising weather can invert almost any boat.
There has been quite a lot of work particularly for ultra high performance multis on systems to prevent inversions – probably the best known/most advance would be upsideup by Ocean Data Systems
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Old 05-06-2019, 11:40   #13
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Re: How many cats have flipped ?

Just some food for thought....

Could it be that we see more pictures of upside down cats than of sunk mono-hulls because it's far easier to take a picture of an upside down cat than a sunk mono-hull? Therefore perhaps the number of pictures one has seen, besides being anecdotal in nature, is more or less meaningless?

Could it be that comparing the righting moment of a cat that's tipped past 90 degrees to a mono-hull isn't meaningful unless you also compare the moment required to get the cat to 90 degrees vs a mono-hull?

Is it possible that most cat's flip end over end rather than to the side given the massive force necessary to get them to 90 degrees?

Is it the case that the force necessary to tip a cat over on its side vastly exceeds the strength of the majority of cat masts, therefore failing to reef leads to de-masting, not flipping over via one's side?

Is it the case that the vast majority of deaths at sea don't occur due to sinking or flipping, therefore the question may be more academic than anything else?

Again, just some things to think about.
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Old 05-06-2019, 12:20   #14
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Re: How many cats have flipped ?

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Could it be that we see more pictures of upside down cats than of sunk mono-hulls because it's far easier to take a picture of an upside down cat than a sunk mono-hull? Therefore perhaps the number of pictures one has seen, besides being anecdotal in nature, is more or less meaningless?
I honestly believe this is the core of the fear. Only in very rare cases where the keel falls off...could a monohull be found floating upside down....typically the keel would drag it to the bottom.
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Old 05-06-2019, 12:31   #15
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Re: How many cats have flipped ?

I suspect the point about some/many/charter cats being under canvassed or over weight lends to their “stability.” My observation was that it would be blowing pretty good, enough for our very heavy monohull to need a reef or two and the cats were sailing with a full press. They were often sailing faster than us, no big trick, but not much faster. So maybe that’s why they dont flip, under canvassed.
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