Sink or Swim??

Discussion in 'Multihulls' started by Richard Woods, May 5, 2009.

  1. Richard Woods
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    Richard Woods Woods Designs

    Or put it another way

    Self righting or unsinkable – which is better??

    One of the perennial arguments between supporters of multihulls and monohulls is “Is it better to float upside down or sink?”

    Notice I used the phrase “self-righting”, not “capsize” for ALL boats can capsize. It is only recently that one specific type can self right after a capsize (providing it doesn't flood and sink first). Yes I'm talking about monohull keel boats with external ballast. Many will be surprised to learn that they are the newest of all sailing vessels, for 150 years ago they didn't exist.

    Multihulls on other hand sailed for thousands of years in the Pacific and Asia, while all European voyages of discovery and trade from the Phoenicians onwards have been in non self righting boats.

    However history isn't relevant to those who say it is better to sink than stay upside down.

    I know I won’t be able to change people’s opinions in this short article, but what I hope to do is to encourage people not to just make glib statements but rather to decide what the real chances of either sinking or capsizing are.

    Let’s be specific.

    A monohull will sink if holed or if flooded by a large wave.
    What are the chances of that, and what can the crew do to prevent it happening?

    A multihull can capsize if blown over by the wind or if overcome by a large breaking wave.
    What are the chances of that, and what can the crew do about it?

    Despite the advent of GPS there are still many collisions with rocks or shore as boats cut corners as they blindly follow their chart plotter.

    Running aground on a monohull is considered a stranding often leading to ship wreck. Whereas multihull sailors will deliberately dry out on a beach - to escape bad weather or even just for fun, say for a BBQ. If the worst happens you are more likely to survive running ashore in a gale on a shallow drafted multihull than a deep keeled monohull.

    Whales have sunk many monohulls, but they aren’t the only floating objects out there. People are a bit coy about reporting facts, so the estimates vary widely, but between 2000 and 10,000 shipping containers are lost each year. Whatever the true number, it is certainly in the thousands. Not all sink immediately, some have been know to float for over a year (those filled with polystyrene/Styrofoam float longest).

    Of course, you don’t need a container to hole your boat; even a log can do that. I write this in British Columbia where every year even ships are damaged by “deadheads” or floating trees, while I once saw a fridge floating off the coast of the UK. Race boats are constantly reporting being damaged by floating objects. In a recent Cape to Rio race a monohull hit a container when 1000 miles from land. It’s crew were rescued just before the boat sunk by a CATAMARAN which took them to Namibia.

    And what can the crew do to avoid such a collision?? Well, to be safe they shouldn’t sail at night, nor sail fast, and obviously there should be someone on the bow on watch at all times. In other words, however careful or prudent a monohull sailor is, he is ALWAYS at risk of a sinking EVERYTIME he goes to sea.

    And what about the large wave problem? Few people actually cruise flush decked boats with no cockpit or hatches, even though they know such boats are safer (I’m thinking of boats like Jester and early Colin Archers). Why? Because they are so impractical as live aboard floating homes. So most monohulls, especially when sailing to windward, and thus well heeled, have large openings very close to the water. And chances are that someone will open a hatch at just the wrong moment, so in fact it doesn’t need that large a wave to get water below. Obviously if it is easy to get a little water below it is also possible to get so much below that the boat is swamped.

    A multihull can capsize if blown over by the wind. What are the chances of that, and what can the crew do about it?

    Weather forecasts are now pretty reliable, and getting better all the time. So 90% of sailors know what the weather will be for their sail. And 90% of the others never get in really bad weather. So the chances of getting “caught out in a blow” are now pretty small for the majority of sailors.

    And even if you are, there is plenty a seamanlike crew can do. Reef for a start. Throughout the history of multihull capsizes it seems the vast majority are either pushing too hard when racing or are monohull sailors not used to sailing multihulls.

    In other words most multihull capsizes are the crews fault, not the boats. And of course the vast majority of multihulls don’t ever capsize because most crews are sensible and reef early.

    A multihull can capsize if overcome by a large breaking wave.
    What are the chances of that, and what can the crew do about it?

    The wider the boat the safer it is in waves. In fact you are just about uncapsizable until the wave height exceeds the beam of the boat. That is a proven, undisputed fact of basic naval architecture. Lie ahull in a catamaran and you’ll just bob up and down. Do that in a monohull and you’re likely to “roll your guts out”.

    It is extremely rare for a cruising catamaran to capsize in waves with no sails set (trimarans are a different matter) because despite what the media say, waves over 20ft high (the average beam of most ocean going multihulls these days) only occur in F10 conditions or more. Even then you are only “at risk” of capsizing. It doesn’t mean you actually will. I know, for “I’ve been there done that”. Not many people can truthfully say, as I can, “then the wind moderated to a F10”. Even in horrific conditions (in a 32ft catamaran) the saloon carpets stayed dry. I once crossed the Bay of Biscay to windward in a gale in a 37ft catamaran. We kept the spare toilet paper in the bilges – it stayed dry.

    And before anyone asks, yes I have had my fair share of being close to sinking on monohulls. Pumping for 20 minutes every two hours to stay afloat when over seven days sail from land isn’t much fun, even if the boat was a Swan 55.

    Having said all that, it isn’t the boat that is important, it’s the crew. Few people survive a sinking, especially if well offshore, while a large number don’t even survive a knockdown even if the boat does (the Fastnet 79 and Queens Birthday storm proved that). Whereas most people do survive a capsize.

    And of course I also have to mention the fact that keels still keep falling off monohulls. And it’s not just a problem on race boats, it also happens on production boats. Well known brands like Contessa, Sigma, Bavaria and J boats have all had failures and lives have been lost. One problem is that the keel cannot be easily inspected, so any failure is always unexpected. In comparison a multihull crossbeam, say, can be inspected daily.

    Nor have I started on the fact that you are far more likely to fall overboard or be injured on a monohull than a multihull, while I suspect that most emergency call outs are as a result of damage to the (single) rudder or engine failure. Most cruising catamarans have two of both. But discussion on that is for another time.

    In fact to me the real question is “why don't monohull sailors demand unsinkable boats”? It isn’t as if they weren’t available, the Belgian yard Etap has made them for years, so too did Sadler in the UK.

    Finally, let’s put the risks of sailing any boat into perspective. According to the official 2001 US Coastguard figures, nearly 500 people died when boating. 350 were in open motor boats, 100 in kayaks/canoes, 50 in personal watercraft.

    So I guess no one drowned when sailing in 2001 in the USA.

    In comparison 24 people were killed skiing in British Columbia in the 2008/9 winter, while over 30 people drown each year in their cars in the UK.

    Richard Woods of Woods Designs

    www.sailingcatamarans.com
     
  2. Boston

    Boston Previous Member

    I would put in a word for positive flotation
    Im ok with swamped, rolled, broken, knocked down, or just plain flattened by a sneaker wave. but sunk is not an option. Any vessel or at least any well designed vessel in my view ( limited since Ive been stuck inland for so long ) should be positively buoyant even if completely swamped for whatever reason. Even badly holed a pleasure craft should always float, or at least mine will once Im back on the water.

    good article
    Im just making a pitch for the unsinkable angle
    as in MHO its the only kind of boat Im ever going to build

    B
     
  3. Ad Hoc
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    Ad Hoc Naval Architect

    "...why don't monohull sailors demand unsinkable boats? ..."

    I'm sure you're familiar with the term 'supply and demand'?

    "..Finally, let’s put the risks of sailing any boat into perspective. According to the official 2001 US Coastguard figures, nearly 500 people died when boating. 350 were in open motor boats, 100 in kayaks/canoes, 50 in personal watercraft..."

    If you wish to use these stat's by "putting them into context"...then you need to supply the raw data. Such as cause of accident, and the sample size etc. Since 500 deaths in a population of some 300million is rather small. Just quoting figures of deaths "in a boat" provides no indication of why and hence a consistent mechanism that can be addressed, if indeed it is necessary...hence my statement above..
     
  4. mydauphin
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    mydauphin Senior Member

    Simple, I would do both - if you can afford it...
     
  5. PAR
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    PAR Yacht Designer/Builder

    Floatation or air chambers are only practical in small craft. Too much interior volume is compromised in larger vessels to warrant implementation, particularly when ballast/displacement ratios are high.

    The argument is timeless and un-ending. If you hole a mono or mutlti, both will likely sink if the breach is large enough. If you go turtle in a multi you can hope you've done so in place you'll be seen fairly quickly and preferably in warm waters. The same is true of a mono, though with the exception of a few designs, you'll find a mono will probably roll over on it's side at some point if not self right. Okay, the boat's a wreck, but you're more visible optically and on radar, plus you might be able to stem leaks and hoist a jury rig.

    All boats, regardless of hull configuration (or number) are a complex set of convoluted compromises. A design brief with the client (or marketing team) makes decisions based on many factors. Not every hole can get plugged, but most get a rubber stopper of sorts, some better then others, some not so much. The compromises we live with are a choice, no one being any less desirable or more then an other, at least to the person commissioning the design foray.

    We can discuss until we're blue in the face and not topple a multi/mono lover off their soap box. So why try? Accept that, like peoples noses, each is unique with application specific requirements and values placed therein. Without sailing a life with their nose on our faces, we can't judge, condemn or criticize, leaving only acceptance as the reasonable route.
     
  6. marshmat
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    marshmat Senior Member

    Putting things in perspective is indeed important. IIRC, only commercial passenger ships, trains and commercial aircraft are statistically safer modes of transportation than yachts. In two of the three cases above, trained professional crew are the main reason they fare so well.

    Now, in the small sizes of boats I'm used to, unsinkable is pretty much a given. At least in theory. Coast Guard level flotation requirements are supposed to see to that. In practice, you can sink anything, given enough overloading, enough neglect, and enough drunken ingenuity.

    I'm not an ocean sailor (yet). And I don't have any particular prejudice one way or the other. But I do think there is a certain pattern that emerges when we look at cats and tris that do end up inverted. A lot of them are high-performance racing machines, intentionally designed to push the limits. With such a boat, you have to expect the crew will hot-dog it a little too far now and then, just as you expect race cars to spin out into the wall on occasion. Of the remaining multis that get into trouble, a large number seem to be the bulky, luxury-heavy deck saloon types intended for hopping between protected anchorages. (You know- the ones with 1'4" under the bridgedeck, 200 square feet of window, and the deck being completely solid except for a trampoline the size of a double bed.)

    So I'm quite convinced that a well-designed cruising multi, engineered for offshore conditions and capable of taking water over the deck without trouble, can be made just as safe as a real self-righting mono (the type that are designed and operated so as not to downflood like crazy if the companionway gets dunked). And vice versa for a well-designed mono being as safe as a floats-after-flipping multi.
     
  7. Chris Ostlind

    Chris Ostlind Previous Member


    No, one doesn't. The numbers speak for themselves as representations of collected data. I suppose that if one wishes to go the bean counter route, then we should also know the color of hair of the dead, the age and sex, the sleeping watch habits and on and on until the whole thing is one huge silly mess... since there just might be some context there.

    Richard did not present a thesis argument, or technical paper for peer review, he presented a series of points to open a discussion on which every open water sailor should have some sort of handle.




    Even one death is traumatic as hell if that person is a friend or loved one. I'm suggesting that this seeks to distill the human experience to data points on a chalkboard.

    Stepping away from the calculator and slipping into one's jammies might get this turned to a discussion among enthusiasts where plain speak is encouraged. Perhaps sensations other than that which one gets in a three piece suit can prevail?

    Yes, data gathering has its place and surely some of us are engaged in too much of it already, but it is not the essence of the sailing experience and I'm of the opinion that Richard was slanting this thread in the human direction more than the technical.
     
  8. Ad Hoc
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    Ad Hoc Naval Architect

    Chris

    So, lets be clear about this:
    When person has had too much to drink...they are intoxicated. This impairs judgement, not just with boats, look at cars. If all the deaths were as a result of intoxication, the conclusion is obvious.
    If all the deaths occurred during extremely dense and thick foggy weather conditions, and found that non of the boats had fog horns or radar and were travelling too fast, again, the conclusion is obvious.
    If all the deaths occurred at night and it was found that the "Capt/person at the helm" did not know the meaning of navigation lights, and caused a collision to sink their boat (even others), again, the conclusion is obvious.
    If all the deaths occurred because the "capt/person at the helm" is at sea in extremely rough conditions, well beyond their seamanship and sank, and their boat had no liferaft, or lifebelts or radio, again, the conclusion is obvious.

    With such qualifiers to the stat's, the conclusions become obvious!

    Statistics are used for a reason, to enhance legislation and to separate the facts from the fiction and supposition as you seem to support. Hopefully it begins the process of enforcement and supporting legislation that prevents incompitent and negligent 'sailors' from getting into their boats and being a danger to others.

    If you wish to focus upon the emotive side, that is your prerogative. But establishing the facts and reason for a death is far more important then if one is is traumatised by said death. Being traumatised helps no one to repeat that same!
     
  9. Landlubber
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    Landlubber Senior Member

    Unfortunately, the choice, mono or cat, it is horsers for courses.

    Basically I am Mono, good design, good condition and designed for the purpose. The mono has a gracious movement, comfortable at sea, and performs well.

    The cat will have a more sudden motion, acellerating and slowing, but most importantly to understand in the ocean, they are harser on the folk on board, as there are two hulls to be affected by the waves, one is sailing free the other has just had a wave hit it and try to stop it, the motion is felt constantly through the deck, and personally I do not like it.
    I do however feel that in protected waters, the multi is second to none. Pleanty of room, good person carrying abilities for entertaining and comfortable , stable platform....just dont add waves.

    there is no perfect boat, there never will be a perfect boat as a boat is a different thing to different people, some carry cargo, some are homes some are floating brothels, but we love em all.
     
  10. rayaldridge
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    rayaldridge Senior Member


    How so? Multis have torn out their bottoms on coral reefs, floated in to the beach, and been repaired. If a multi is built of unsinkable materials-- foam or wood, for example, it can't sink. Even if it breaks up, the component bits will mostly float.

    I believe that the issue Richard is raising here is ultimate safety offshore, and I think that in this narrow category the properly-designed multi has an undeniable advantage over a properly-designed ballasted monohull, for many of the reasons Richard cites. Chris White attempted a similar analysis in his book that covers much of the same ground. I found it completely convincing, despite the fact that when I first read it, I owned a monohull yacht.

    I believe there is indeed a point to making these arguments. Our audience here consists almost entirely of folks who go to sea for pleasure, not out of necessity. They want the most fun, they want the most safety. 50 years ago, almost no serious sailors were interested in multihulls. Now the multihull segment of the boat manufacturing industry has become the healthiest remaining segment of that chancy business. Somewhere along the line, minds have been changed. I see no reason why that process will not continue.
     
  11. Richard Woods
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    Richard Woods Woods Designs

    I thought I had written too much as it was, so didn't include the basic accident data from the US Coastguard.

    But I post below what I found after a very brief google search. I am sure you can find and analyse the data more completely (to be honest I don't have the time and it wasn't really relevant to the points I was trying to make)

    =========================

    Boating Accidents at a Glance
    *The Coast Guard received reports for a total of 6,419 recreational boating accidents in 2001. The casualty data for 2001 showed 681 fatalities and 4,274 injuries.
    *Four hundred and ninety-eight (498) boaters drowned in 2001. Life jackets could have saved the lives of approximately 420 boaters who drowned. In 2001, approximately eight out of every 10 victims in fatal boating accidents were not wearing life jackets. Boaters continue to be at a greater risk of dying when involved in an accident during the fall and winter months than in the summer. Besides the colder weather and water, there are fewer boaters and patrol officers in the area to rescue boaters in distress. When waters are below 60 degrees Fahrenheit, hypothermia can set in quickly. Those who hunt and fish from boats, especially in colder weather, need to dress for possible immersion and wear their life jackets. Boaters in larger bodies of water should also take advantage of using available distress alerting and position indicating technologies to improve their chances of survival if a mishap occurs.
    *Eighty-five (85) percent of fatalities occurred on boats less than 26 feet in length. Seventy-two (72) percent of those victims drowned. Specifically, 322 fatalities occurred on boats less than 16 feet in length and 254 occurred on boats 16 to less than 26 feet in length.
    *Alcohol involvement in fatal accidents accounted for thirty-four (34) percent of all boating fatalities — up eight (8) percent from 1999. A Coast Guard study estimates that boat operators with a blood alcohol concentration above .10 percent are estimated to be more than 10 times as likely to be killed in a boating accident than boat operators with zero blood alcohol concentration.
    *Approximately eighty (80) percent of all boating fatalities occurred on boats where the operator had not completed a boating safety education course.
    *Nearly 70 percent of all reported accidents involve operator controllable factors. The primary causes of accidents are operator inattention, careless/reckless operation, operator inexperience, operating at an unsafe speed, and no proper lookout.
    *”Capsizings” and “Falls Overboard” accounted for 386 fatalities, nearly sixty (60) percent of all reported boating fatalities. Nine out of every 10 of those victims drowned . “Collision with Another Vessel” was the most reported type of accident . These accidents resulted in 1,366 injuries and accounted for nearly nine (9) million dollars in property damage.
    *Twenty-six (26) children age 12 and under lost their lives while boating in 2001. One hundred and thirty-seven (137) boaters died in the 40-49 age group category — the highest number reported for any age group.
    *Three hundred and fifty-two (352) fatalities occurred with the use of open motorboats, just over half of all boating fatalities. One hundred and one (101) people lost their lives while using canoes/kayaks in 2001. Approximately ninety-three (93) percent of canoe/kayak deaths were caused by drowning. Fifty (50) fatalities occurred with the use of Personal Watercraft (PWC), the lowest number of PWC fatalities reported since 1993. Approximately eighty (80) percent of all reported injuries were associated with the use of open motorboats (46%) and PWC (34%). Lacerations were the most reported type of injury for open motorboats. For PWC, broken bones were the most often reported type of injury.
    Data Provided by: U.S. Department of Transportation, United States Coast Guard

    =================

    Richard Woods of Woods Designs

    www.sailingcatamarans.com
     
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  12. rayaldridge
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    rayaldridge Senior Member

    This strikes me as a very unusual view. Most folks who've sailed offshore in both monohulls and cats, as I have, would say, I think, that the cats are vastly more comfortable.

    For one thing, they don't roll their guts out downwind.

    If you were to take a poll of arriving wives in Barbados in December and January, I think you'd find that the ones who made the milk run in cats are a lot happier about the conditions aboard than those who come across in monohulls. I specify wives in this scenario, because in my experience women seem less affected by prior ideas of what constitutes a proper yacht, and also, they seem to be much more willing to air complaints about their boats than the proud captains of said proper yachts.

    I hereby volunteer to make this important survey, if someone will sponsor me to the extent of a round-trip ticket to Bridgetown next winter.

    Anyone?
     
  13. Ad Hoc
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    Ad Hoc Naval Architect

    Richard
    very very interesting stats
    "...Four hundred and ninety-eight (498) boaters drowned in 2001. Life jackets could have saved the lives of approximately 420 boaters who drowned. In 2001, approximately eight out of every 10 victims in fatal boating accidents were not wearing life jackets..."
    S0, 80~85% of all 'sailors' were not wearing a life jacket that could have prevented their deaths.
    Whether a boat is unsinkable or not, doesn't account for shear stupidity and negligence of owners!
    As with most aspect of 'death' in transportation, it is often found that around 80~90% of such deaths occur owing to "human error". Yet legislation becomes harder and more difficult, which does not influence the stupidity of those losing their lives at sea in the first place one bit!

    The 'Marchioness' and 'Herald of Free Enterprise' being typical examples of human error. And.... with 'experienced' crews!
     
  14. Chris Ostlind

    Chris Ostlind Previous Member

    Nothing about statistics is obvious. They are as misleading as any other bit of information and just as likely abused, rather than used for good deeds.

    Since you brought up the car analogy.... the real reason people die in cars after drinking is not because of the drinking. It's because they got into the car. Is there a column in the data for that inconvenient reality?

    Ever had someone die in an accident? Of any kind? Did running a bunch of data points on the whole deal get them back for you? No, I thought not.

    If you really want someone to "get it" from the collected data after the fact, you have to put the message in a human form; something they can feel, or you might as well be talking to a wall. Human beings do not naturally take to lists of numbers. They respond to visceral comprehension and the emotions that those feelings create.

    It's not me making that up to argue a point. It's as plain to see in just about every bit of marketing material that is made every day. You want someone to be moved by argument, you do not hit them with a list of numbers. Well, unless you really like getting ignored, you don't.

    When we get the emotional side of the argument, we are connected. Once that is accomplished, you just may have an opportunity to address a small element of the statistical data to support the presentation. Ignore this reality at your own risk, or limit your scope to other fellow data jockeys.
     

  15. Boston

    Boston Previous Member

    Fantastic data Rich
    give me the facts and nothing but the facts any day
    your post is perfect for determining how well my own plans stack up
    for me thats what this hole site is all about
    learning as much as I can from the mistakes of others
    as well as paying close attention to the successes and how they were achieved

    I was always kinda scared of the water
    nothing like a little good old fashioned respect to make you think twice about doing something completely stupid
    Ive seen that if the ocean wants you
    its got you
    but luck favors the prepared
    and I love the water anyway

    thanks for the tips
    you got a few points from me on that one

    cheers
    B

     
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