how do cats handle big waves?

Thanks Catsketcher, I have a similar space aft but am trying for more. There would be plenty of buoyancy in the unflooded portions of the amas, wings and main hull to keep things floating high if something didn't work. I haven't given up on self righting either, it is one reason I wanted to build and test a model. when things go wrong it always seems like nobody is there! I remember reading about the Rose, it seemed similar to a Cross. I think relying on just airlock though is taking a huge chance. What if the mast punctured an ama or the cat hit debris that flooded a bow then went over etc....Charles Kantner in some of his books has good ideas for floatation, using empty plastic bottles in the wings and other spaces etc...They can still be removed for inspection and open the possibility of adjusting your trim should it be needed. Cats trim stern down because of the engines and batteries ? Having an idea of how your boat will float is important. I agree that it isn't good seamanship to pretend these things can't happen, having a plan always helps! Not to mention a manual watermaker.....

 

Page one of the Loch Crowther design notes here http://www.boatdesign.net/forums/po...ot-about-crowther-cat-haul-designs-14969.html mention unable to capsize a cat (model) in 31 foot waves compared to easily capsizing a mono in 24 foot waves.
Tests with conventional 40ft monos after the fastnet disaster showed they are easily capsizable in 12 ft waves.

 

I know some of you are passionate about cats and have your own reasons for being so, but in all humble curiosity what is it about a cat that could possibly make up for a catastrophic capsize in difficult conditions. If you're on the water, you run the risk of being caught out, and if so and your in a cat, thing capsizes, well, I suppose the real question is whats the survival rate, as apposed to a mono's of similar length. Tragic loss for tragic loss what are the numbers cause it sounds like capsizing in a cat is a one way ticket.

sorry if it sounds calice but whats the survival rate comparison

 

Properly prepared for living inverted a multihull of any kind can be far safer than a monohull which has the big problem of sinking. To be comparable a monohull should have positive flotation and a means of balance should it lose its ballast generated stability. It is easier to roll a monohull in big seas than it is to flip a multihull but both can be seaworthy with proper preparation. I sailed a lot on monohulls but my boat always had positive flotation. It means giving up space but all the room in the world doesn't help if you're not afloat to enjoy it. The criticisms of modern catamaran marketing are equally valid because their edge on safety is lost if no one prepares them properly. A multihull is far more comfortable at sea and reducing fatigue can go a long way towards reducing operator error. I'm sure you'll get a lot of response on this, I think a well rounded sailor ought to be familiar with all types of boats, then he or she really has a knowledge base to choose from.

 

Im not so sure that a fair assessment could be had by comparing the incidence of keel failure in a mono with the incidence if fatal injury in a multi. Keel failure is a issue generally associated with class vessels. Multihull capsize is an across the board problem. Lack of positive buoyancy is its own issue

not trying to be difficult but again
what are the numbers

proper preparation should average itself out and so should not be a factor in a overall review of incidences had in each kind of hull. Yes it would mater if we were not talking averages but I just want to know what the average survival rate in in a monohull that capsizes and in a multihull that capsizes

on an individual basis yes
preparation is everything
but whats the overall numbers say

seems like the issue of safety can be answered best by just looking at the numbers

how many capsizes in each
now many fatalities in each

 

Good question Boston

I must have been around a fair bit because this is the perennial good question that alwyas needs to be heeded. If you go and buy Jim Brown's fabulous book - The case for the cruising trimaran - he gets asked this question at the start of the book and the whole book is an attempt to answer it. The book is now back in print and if you don't have get it and read it - go to Outrig.net.

As to my take on the question

I feel that cat design has gone backwards in terms of safety in the last ten years or so. Up until the 90s cats were the province of people who had to seriously consider challenging stereotypes in order to own one. As such they were always facing the capsize question as it was uttered by every third mono sailor they met. This is not the case today. Still we are no where near the carnage days of the 60s through to the 80s. In the 60s trimarans were the cause of many deaths in the Pacific. If is recall correctly there were

-Waka Toru - capsized going to Lord Howe - 8 deaths from a family and female crew
-Vagabond - wrecked on Breaksea spit - 2 deaths
-Bandersnatch - capsized and lost a float in Bass Strait returning from the only multi Hobart race - 4 deaths
-Privateer - Hedley Nicol and two crew were lost sailing to the US

These are the ones of the top of my head in the late 60s. With the advent of EPIRBS and GPS, survival suits and better designs the problems were greatly reduced. Sadly the increased safety we now have with heavier and beamier designs is being eroded by increased accomodation and higher center of gravity. It is really a lot harder for the multi designer. A monohull designer can just say "Carry a life raft". A multi designer can't really as the whole idea of a multi is to give you a better platform than the life raft. Jim Brown sorts designs into two groups. One that will support you and one that needs a raft. Sadly most cat sailors have boats that need a raft for survival but do not carry one. Even if they do the raft needs to have special access built into the boat so that it can be retrieved upright or inverted. Again Jim Brown designed special compartments into his designs for this.

Maybe it is because cat design has been largely taken over by stylists and interior designers rather than yacht designers that these problems arise. Listen to how people choose their designs - often I hear people say they will choose between designs as they want a galley up - why? Have they tried to cook in a seaway in a high galley or worked out how much higher the CG will be from this? No it just looks modern and is easier at anchor. It may be a good detail to have but it would be nice if people put as much care into their hull lines and safety features as they did into their galley arrangement.

As to Boston's very good question - we don't know. We do know that capsize and sinking are rare and that you run more risk of falling overboard or driving up on a reef than either. The question is made harder by the fact that the worse a good cat can do (after break up or burn) is capsize. At least you are left with the boat in the last case. For John Glennie and his three crew in the Rose Noelle they were looked after by the boat even after it flipped. They would not have survivied long in NZ waters in a raft but they may not have sunk in the same storm. Sadly many cats can't even be thought of as unsinkable as they carry large batteries, diesels, rigging, solid glass laminates and heavy anchor gear to act as ballast enough to make them deep six and have too few watertight compartments to give a reasonable platform to live on with the hulls stove in.

I guess my personal answer to Boston is that some cats are much safer than others and you can't group them all together. Some are far more resistant to flipping and better built. Some have capsize features built in but most have none. Your chances of survival are greatly increased in those that are designed to be seaworthy first and roomy second.

cheers

Phil

 

I agree that keel failure is relatively rare, I pointed out that flotation in a mono hull should allow for it. However sinking in a monohull is anything but rare, even in calm waters a hose clamp failure has sent many a lead lugger to the bottom. What do your numbers say? I own and sail both so my mind is made up and the conclusion is preparation. All things being equal I'll take the well prepared multihull any day. To find an answer to your question preparation will have to be taken into account and cruisers compared to the same and racers the same. Some years ago the safety clearly favored multihulls when comparing what the craft were used for. In recent years the numbers may have changed as people new to boats may not have made the preparations. In truth most people don't die when their boat capsizes though many do when a monohull sinks because of the time factor. Lets see hours to days to weeks to decide on the life raft or seconds to minutes before you sink......Thats good enough math for me but Boat U.S. and the like may have the numbers, just read the stories to make sure your comparing what the boat was doing. P.S to Phil, Bandersnatch hit a whale and Vagabond had to be lost to try sailing across BreakSea Spit and on Privateer only Hedley Nicol would have been trying to sail in winds of 70 knots and they lasted long enough to try righting the boat by sawing off an ama! In truth it is sad to see lessons learned forgotten, we should send the dock crowd designers to sea with their clients.

 

agreed, Im aiming for comparing apples to apples
how many boats went over yet did not sink and how many survived
or how many went over and came back upright
bla bla bla you get the picture
apples to apples all the way no biased involved

I would reiterate the need to offer a moment to the lives lost as my literary style oft places me at odds with the more politically correct, however the issue of survival may not be precluded by the reality of loss. Its a subject that deserves an informed review, unfortunately it sounds like the numbers are simply not available. Seems unconscionable that no one would be keeping track of something like this, the insurance industry perhaps?

B

 

Going on the increased acceptance and reduction of price of insurance premiums over the years for multi's one would suggest they have been keeping track and have decided that they are a better risk and safer.

 

There are, so far as I know, no official, widely accepted numbers of the kind you'd like to see.

Chris White, in his excellent book, attempted an analysis of fatal accidents over a period of years, using Coast Guard data on incidents in which lives were lost aboard pleasure boats in the CG jurisdiction. His conclusion was that multihulls are less likely to kill their crews. I won't attempt to convey the stats; read the book.

I think, however, that if you apply a little common sense and logic to the problem, and you have no strong bias regarding the conclusion, it's hard not to think that multis (and cats in particular) are safer.

Both kinds of boats are vulnerable to being run down by commercial ships and fishing boats, with disastrous consequences. Both can burn. But apart from those disasters, the worst thing that can happen to a mono is sinking. (While there are a few ballasted monos with positive flotation, they are extremely rare.) The worst thing for a multi is capsize. The former disaster leaves you swimming or in a raft. The latter leaves you afloat on a large platform with all your supplies, and much better chance of being spotted by rescuers. It seems to me that the latter disaster is by its nature much more survivable.

There are many other factors to consider as well, and they mostly give the safety edge to multis. For example, the greatest number of fatalities are due to man overboard. The wide stable decks of a multi are intrinsically safer than the heeled narrow deck of a mono. Human error accounts for many fatal accidents, and often fatigue is a large factor, Sailing in a multi is less fatiguing, because there's less heeling and less rolling.

The shallow draft is a safety factor, combined with the wide stance of modern cats. Where I live, the beaches are sand, with almost no rocks. Out sailing in the Gulf in an onshore gale, it's comforting to know that if something went wrong and we were blown ashore, we would be a lot more likely to survive beaching through the surf than a keelboat would. Even in areas with off-lying reefs, the cat is safer. A number of multihull sailors have survived hitting a reef, because although the reef may chew away the hulls, the remnants will float and if they make it past the reef, they'll float ashore safely.

At any rate, I think there's little real controversy anymore among folks that are able to consider the question without bias. There's certainly nothing wrong with preferring monohulls, but monohull sailors should understand that they sail a more dangerous boat-- unless they are willing to have positive flotation, which is of course much more difficult when you must offset the weight of a massive keel. In much the same way, multihull sailors have to accept that they can't carry as much stuff, and that they'll have trouble finding berths at marinas.

 

So, the message is; "If one is biased, he prefers a mono. If unbiased, cats are safer" (particularly a lightly built, not solid glass, one?). You guys and your unflippable cats - give me one of those damned things - I guarantee I can flip it. And you may not know it but I do - There are seas that you cannot get back to your overturned cat after you have been ejected nor wud you survive getting close to the flailing wreck. The option of a mono isn't to let it sink then get in a raft - it is to not let it sink. The reef thing I'll give you.

 

Quite a few times whether a boat sinks or not is out of your hands, collision damage with debris, some folk have been even sunk by whales etc... People I knew on a crabber were lost when it iced up, capsized and sank, a not unusual occurrence up north. To be fair the Fastnet disaster showed most people left their boats when they didn't have to, many studies have shown people being lost on the life raft transfer so not panicking is important. In all cases being prepared makes the difference no matter how many hulls you have. The navy did a study that showed heeling past 10 degrees started interfering with human functioning so whatever you have sail it flat. It is wonderful that we can choose the configuration we prefer because they all have something to offer, I certainly didn't not sail because I had a monohull but I sure kept my eyes open for a multihull. I think the biased un biased comparison can only be made after you spend sea time on both monos and multihulls. Until then the cat guys are preaching to the choir and the ballasted barnacles are happy with where they're at.

 

I am definitely a multi fan, but I would not state this as squarely.

Monohulls roll over, multihulls flip.
If the vessel is built to be durable, both survive.
If not, mono will sink, multi will break (or what exactly it does?).

We can discuss
- magnitude of forces on crew when rolling over vs flipping
- the failure modes and their probability which lead to flood/breakage
- the relative merits of sitting in a liferaft or swimming around broken boat parts

Yes, you actually stated that probability of failures leading to fatal breakage is lower for multis when we compare similar size, with which I am not arguing.

 

Ok so both mono's and multi's have pro's and conn's, some will prefer the mono and some the multi, whichever is up to you.

The worst comes out when the going gets less good, ok so how do one rig the boat, what should you have and what decisions should one make to have the best chance or surviving - and I deliberately try to swing the argument away from comparing the boats, it's going to do you no good when the trouble starts to argue which type of boat you should have been on - you will have to make do what you have.

The thread started how do cats handle big waves, but I'd like to hear from the other boats also. I think the comparasson should be what to expect in the different boat types for the same weather instead.

I once was on the water and a storm was approaching like a big black blanket. No warning forehand, no wind. Looking up it was just there and minutes to spare. So you quickly dry yourself off from swimming and get inside so you don't get wet when it begins to rain What else ?

 

Ok,

Count the crew (one, two, three...)
You put all loose things away, close hatches
Dress up for the occasion, wet suits, life jackets
Have food and water at the ready
Let someone know where / what is happening, HF or Sat phone
Get the forecast, you obviously missed it
Do you stay or go