The perils of edgy design offshore

Discussion in 'Sailboats' started by CutOnce, Jul 18, 2011.

  1. eyschulman
    Joined: Jul 2011
    Posts: 253
    Likes: 8, Points: 18, Legacy Rep: 77
    Location: seattle Wa USA

    eyschulman Senior Member

    If next year two people die after being hit with a low boom will booms with less than 7 ft clearance from deck need to be outlawed. There is no clear place to draw the line on which design elements are safe enough. People die raceing sail boats. Many many more people die yearly from drinking,smoking,driving and food poisoning things easier to prevent than the interaction of bad weather and its interplay with boat design. If new designs are risky raceing is where they get tested. I have been out in weather that probably would have destroyed a goodly number of that fleet and no race committe legislation would make a difference.
     
    1 person likes this.
  2. sharpii2
    Joined: May 2004
    Posts: 2,082
    Likes: 223, Points: 63, Legacy Rep: 611
    Location: Michigan, USA

    sharpii2 Senior Member

    It is interesting to see this boat compared to a multihull, presumably a trimaran.

    I'll admit, the deck plan looks similar. It looks like a narrow tri with its floats shorn off.

    And that is the difference.

    Multihulls have very high initial stability, while this boat has high moveable ballast stability. The problem is that for it to have anywhere near its max stability, the moveable ballast has to be properly deployed on the windward side. If it is anywhere else, even in the middle of the boat, it is completely ineffective.

    With a trimaran, the "ballast" is always to windward because it is concentrated in the main hull. In wild conditions, this can be very useful. If the boat broaches, putting the other side to the wind, there is always the weight in the main hull and the buoyancy of the leeward float to hold it upright.

    Shorn of its sails, it would be very hard to capsize.

    This boat, even minus its sails, is much easier. The leeward wing digs in and the wind gets under the windward wing and over she goes. With only four to six foot waves, this seems like the most likely scenario. How else could a fourteen foot wide boat be capsized by waves less than half its Beam in height?

    It seems particularly tragic that doing the right thing in that situation with most boats, may have been the wrong thing to do with this one. Given my perceived weakness in the design, it may have been better keeping it sailing. The idea would be to bleed off as much force of the wind by running before it as possible. But in that case, a sudden shift in the wind or a broach would have been deadly.

    Either that or put some kind of sea anchor out to keep its bow to the wind. But there would have to be time to do this.

    I think the bottom line is this boat has little right to call itself a keel boat. The ballast keel has proven itself so ineffective it might as well be called vestigial. A real keel boat should be able to be counted on to reach its maximum righting moment somewhere between 60 and 90 degrees of heel. This way, it is at least difficult to blow over. It reaches its maximum righting moment at the time the sails and mast have lost most of their capsize moment and the keel has lost most of its effectiveness in keeping the boat from sliding off to leeward.

    This boat may have technically met that test, if it wasn't for the windward wing replacing the sails and mast for capsize moment and the leeward wing acting as a very effective new keel, keeping the boat from sliding off to leeward, like a more conventional keel boat would in that situation.
     
  3. Gary Baigent
    Joined: Jul 2005
    Posts: 3,014
    Likes: 128, Points: 63, Legacy Rep: 509
    Location: auckland nz

    Gary Baigent Senior Member

    I read it all - usual Sailing Anarchy **** fight but amongst the mouth frothers, some sense there too. Actually looking at the stern views of the Kiwi 35, the wing setup is quite different to the Young Rocket 31 and Extreme or numbers of Elliotts here (and the later Whitbread/Volvo/Open designs) because they are truly flared hulls, and not wing additions. There is no doubt that the K35's wings would dig in. Having said that, Doug Lord mentioned the digging in may very well have saved crew from being washed away ... but would also have helped to capsize. A flared hull will skid whereas a wing will dig. The point that the headsail was unfurled, or still on the forestay in the waterlogged photograph (when apparently early talk was that all sails were dropped) leads me to think that it wasn't dropped at all. Although no one knows what actually happened at this stage, would have been better to have all sails down and lashed and fore reached under bare poles ... but 20/20 hindsight is real easy.
    Mike not Michael, my point about W60's getting into strife was just that, **** happens, even to champion kiwi sailors.
     

    Attached Files:

  4. magwas
    Joined: Oct 2009
    Posts: 287
    Likes: 8, Points: 18, Legacy Rep: 47
    Location: Hungary

    magwas Senior Member

    The word "multihull" did not came out in this debate so many times without a reason.

    This boat is not multihull, but also definitely not a usual monohull.

    It would be interesting to see this incident analized from the multihull viewpoint. I mean that "no rightning after capsize" is a property usually associated to multihulls. There are technical and procedural measurements associated to this fact, and adhering these measures mean that a multihull is seaworthy. Maybe looking over these measures and seeing how they apply to this boat would provide some insight.

    I am no expert, so I can think of only two such considerations:
    1. initial stability. Multihulls have nearly the same tranverse initial stability than longitudinal one. Obviously it is hard to achieve with a monohull (a wing might contribute something, I don't know). A mitigating measure might have been to keep the boat perpendicular to the waves. Does it make sense? Did the crew tried something like that? How could it be achieved?

    2. Room to weather out in case of capsize. As I recall monohulls have to have an entry above water in capsized state, and parts of the cabin should be above the waterline. Did this boat had something like this?


    As an aside note: in 07.15 there was the biggest freshwater race in Europe, in lake Balaton, the Kék Szalag (Blue Ribbon) race. We had some foul weather here as well. 90km/h gusts and 70-80km/h sustained winds for ten hours. Of the 589 entries 339 have made it. One boat have sunk, no serious injuries to any people. The winged race machines haven't got from the storm, they were too fast. Otherways my impression was that all problems had to do something with problems in seamanship.
     
  5. MikeJohns
    Joined: Aug 2004
    Posts: 3,192
    Likes: 208, Points: 63, Legacy Rep: 2054
    Location: Australia

    MikeJohns Senior Member

    The predictive seaworthiness of any boat from a scientific, validated approach doesn't change. Some people seem to have a problem with that.
    You can have the seaworthiness of your boat quite accurately assessed from some relatively straight-forward indicators.

    You can compromise a lot of features for speed but you should understand those compromises, not deny them. People can decide what the acceptable risk is for a particular venue and stand by that decision with full knowledge and disclosure. Not to try and obfuscate the issue of dangerous craft design.

    As for your fear of safety creep, understand that scattered data doesn't count. We don't need to push the bar so that every boat is intrinsically safe. It's based on reasonable risk assessment. It would be sensible for a race organiser to apply such a risk assessment and weed out the coastal racers in an offshore event to protect the gamblers from themselves ( or get them to sign a very clear disclaimer !)

    Every boat owner should be aware of the limitations of their vessel and that assessment of safety and suitability should be made clearly known to everyone aboard.
    In Europe that has become mandatory for production boats whether commercial or private leisure. That doesn't stop you privately operating the boat outside of it's recommended area but it can make you liable if you kill someone in the process.

    What doesn't help anyone is vehement denial that a vessel which lacks sensible seaworthiness criteria is somehow safe unless the weather intervenes, and if this occurs then it's the weathers fault and has nothing to do with the inherently dangerous design.

    I said before that it's human nature to gamble, but you should have enough information to know the odds and blame no-one but yourself if you lose.
     
  6. MikeJohns
    Joined: Aug 2004
    Posts: 3,192
    Likes: 208, Points: 63, Legacy Rep: 2054
    Location: Australia

    MikeJohns Senior Member

    And it will dig early and it will add a significant turning moment to roll the hull. Couple that with possible wind and or wave action on the upturned wing, and you have the impeller action I was trying to get through to Doug when he was denying that there was nothing untoward in the design.

    This feature significantly reduces the seaworthiness of the craft. Couple that with high inverted stability and you have a very poor design to take offshore.

    It had absolutely nothing to do with the design of Wingnuts at all.
     
  7. Paul J. Nolan
    Joined: Sep 2009
    Posts: 19
    Likes: 2, Points: 0, Legacy Rep: 51
    Location: Seattle

    Paul J. Nolan Junior Member

    People can expend themselves endlessly arguing about the inadequate number of lifeboats, lack of 24 hour radio watch, water-tight bulkheads not going all the way to the deck, or inferior rivets, but the root cause of the Titanic disaster was the decision of the master to run at full speed through an ice field at night. It was a failure of basic seamanship. All the rest is immaterial, simply grist for jawboning.

    All this talk about design parameters, wings, ballast, righting moment, etc. just serves to obscure the truth: Wingnuts was laughably unseaworthy and such would be apparent at even a casual glance to any sailor worth his salt. And yet people set off for deep water in crudbuckets like that one all the time. Why?

    Aside from general ignorance and foolishness, there are a couple of things I have noticed in the decades between the CCA cruising boats and today's "craft." One is the Disneyland Effect (Hey! There's a grizzly bear! Let's get a better look!) This is the idea that bad things won't happen and if they do someone will be there to save you. This is what causes people, when the bilgewater is around their ankles and rising, to reach for a radio transmitter rather than a bucket. Once the idea of self-sufficiency was universal among ocean racing sailors. World-wide radio communications have utterly destroyed that way of thinking and replaced it with the expectation of search and rescue always being available. The other phenomenon I see repeatedly is Group Think. Someone on this thread earlier asked if a respondent thought all multihulls were unseaworthy. Well, the answer is, yes, they are. But so many people put to sea in them repeatedly, racing and cruising, that people's attitude towards them changes, despite the well-known dangers of unballasted boats offshore. It is the same with single-handed offshore racing. People who sail large vessels at 20+ knots with no one on watch should be imprisoned. Instead, group think causes them to be venerated for behavior so lubberly that it verges on criminal.

    The problem with engaging in a bad practice, whether it is smoking, drunken driving, writing naked call options, or going offshore in grossly unsuitable craft is that you can get away with it time after time, often for a very long time indeed.

    Until you can't.

    Paul
     
  8. Doug Lord
    Joined: May 2009
    Posts: 16,679
    Likes: 343, Points: 93, Legacy Rep: 1362
    Location: Cocoa, Florida

    Doug Lord Flight Ready

    The Perils of Edgy Weather in Any Boat

    ===============
    Wow! Now, lets hear Mike answer the question......And yes it is relevant to the design of Wingnuts and the future design of high performance monohulls. And to potential safety considerations that could work for these boats and are already adopted for multihull design.
     
  9. Stumble
    Joined: Oct 2008
    Posts: 1,909
    Likes: 71, Points: 48, Legacy Rep: 739
    Location: New Orleans

    Stumble Senior Member

    I have avoided this thread mostly, but feel like some of the posts here have become a tad critical of a design they know little about.


    I have spent a good bit of time on a sister ship to this boat (another kiwi 35 named Turkey Wings). And the reality is that the boat is as you might expect highly unstable. However when weight is concentrated low and inboard ( in the cabin) the boat quickly stiffens, and is quite stable under pretty much all conditions.

    The real hallmark of this boat though is that as soon as a wing hits the water, the boat quickly slows down, and the nose dives leeward. If the sails are set for upwind this can be a problem, since as soon as the boat turns down the sails act like a wall, and drive the boat further over. However this is where it stops.

    As soon as the wing hits the water, the amount of added righting moment is huge. Those wings weigh nothing, and are air filled and water tight. Secondly the boat doesn't trip over the wing, the boat starts to slide sideways quickly as only a few inches of the edge dig in. When this happens ( the boat sliding sideways) the hulls are designed in such away that the water is forced off the back end driving the bow back up into the wind. In effect the entire wing acts like a rudder.

    This can result in a cycling where the boat heels over, the wings then push the boat back up, the boat rights itself, then the sails drive it down again. This is a pretty uncomfortable motion, but occurs at around 40 degrees of heel, and the normal procedure is to dump the main and the boat will self right quickly. Clearly that did not happen here.

    Now compare this to the boat that the wind readings are from. The owner there indicated that they were pinned at 90 degrees for 10-15 minutes. Had the boat rolled anymore it would have sunk as hatches and through hulls were submerged.

    These are quite different motions, and honestly I can't say that I know which would be worse. But I can tell you that the Kiwi in very heavy air (I have been out on them up to around 35kn ) is very controllable.



    By comparison the most modern wing boat I have been out on is named Danger Zone. A R/P custom 32. It's wings have the opposite effect from the Kiwi. As soon as the wing hits the water, the design of the wing has no effect on the heading of the boat. I don't know how this is accomplished so I won't speculate, but the boat has no tendency to turn as the wing is submerged. Does this make the boat more or less sea worthy? I have idea, but think it is interesting to note how different shaped wings behave differently.


    Personally I think this tragedy was the result of a very strong microburst where winds can exceed 160kn. Followed by a string of very bad luck. Perhaps exacerbated by a design flaw. But i personally have seen masts ripped off of a boat in winds less than that this kiwi experienced. And just a few miles away from the Kiwi another traditional keel boat sank from in flooding when they were pinned over. Of course the kiwi's story is more tragic as people died, but until we know why they died (drowning, or hit with a boom in the head) it is premature to ascribe the fatalities to a suspected cause.
     
  10. Gary Baigent
    Joined: Jul 2005
    Posts: 3,014
    Likes: 128, Points: 63, Legacy Rep: 509
    Location: auckland nz

    Gary Baigent Senior Member

    Mike not Michael, my point, repeat again, my point re the W60's (and other 60 types who have also been flattened) was that the flared hull allowed them to survive, providing a skidding shape and also buoyancy where it was needed, at deck level. Agreed, Wingnuts did not have this feature.
     
  11. Ad Hoc
    Joined: Oct 2008
    Posts: 7,083
    Likes: 1,015, Points: 113, Legacy Rep: 2488
    Location: Japan

    Ad Hoc Naval Architect

    Far be it for me to wade into this highly emotive debate. However as noted by both Paul J. Nolan & MikeJohns there is little common sense actual facts being discussed.

    This is then picked up by Doug, questioning Pauls statement here:

    So, to avoid all emotion and “feeling” and “I think” debates, let’s look at some very simple well known facts, courtesy of Marchaj:

    Firstly ballast versus no ballast:

    Y-stab-1.jpg

    Oh simple, ballast has better stability.

    Well, what about catamarans?

    Y-stab-2.jpg

    Oh look ballasted boat has better stability again.

    By why choose a catamaran:

    Y-stab-3.jpg

    Oh not rocket science, it goes faster…thus shall win more races owing to superior speed characteristics.

    But the killer line, missed probably by all is this one:

    So let’s look at the evidence again:

    Y-stab-4.jpg

    Oh look the further you go out to sea, ie offshore, you get stronger winds and wow, bigger waves! So, with such strong wind and big waves, which would be considered safe and seaworthy and which would be considered unseaworthy…..yup, you should have it by now, if you have joined the dots correctly.

    Oh, for those that wish to pipe in with Ellen McArthur etc. Look at Yuri Gagarin, Chuck Jaeger, Neil Armstrong, Capt. Cook, Capt. Scott, Sir Ranulph Fiennes etc etc….are these normal people, no, they are driven, highly motivated individuals. The keep going until they can’t go anymore or die, usually both at the same time. Great explorers, greater examples of human spirit…but they accept the risks (their life), and know there are risks, very serious and real risks, but they are driven and do it anyway.

    Simple well known facts of design and the environment the design is to be in shall dictate what is a risk or not. It does not alter the design it does not alter the environment, the risk remains, what you elect to do with the known risk, is the variable. If you elect to remain inshore knowing the simple facts, the risk is greatly reduced, the design has not been changed. But, choosing to ignore the risk or not even make an attempt to mitigate it, is simple foolishness and ignorance.
     
  12. Gary Baigent
    Joined: Jul 2005
    Posts: 3,014
    Likes: 128, Points: 63, Legacy Rep: 509
    Location: auckland nz

    Gary Baigent Senior Member

    Ad Hoc, you're full of it, aren't you? You think the owner of a winged lightweight monohull has nothing in common with your disparate list of explorers, pioneers and adventurers ... perhaps not to quite the same extreme degree ... but definitely of the same ilk. You realize you're insulting the recently deceased owner with your garbled nonsense.
     
  13. Doug Lord
    Joined: May 2009
    Posts: 16,679
    Likes: 343, Points: 93, Legacy Rep: 1362
    Location: Cocoa, Florida

    Doug Lord Flight Ready

    The Perils of Edgy Weather in Any Boat

    Well said, Mr. Baigent.
     
  14. Ad Hoc
    Joined: Oct 2008
    Posts: 7,083
    Likes: 1,015, Points: 113, Legacy Rep: 2488
    Location: Japan

    Ad Hoc Naval Architect

    Would please care to explain where this “emotion” criterion is shown on the graphs of stability with and without ballast from factual design criteria...and how this emotion criterion relates to wind velocity and fetch?

    If you wish to debate the motive side, please feel free….im sure you’ll have many takers, with views opines and feelings.

    If you wish to debate the technical aspects, then please reply accordingly, and point out where the data posted above, is incorrect.
     

  15. Paul J. Nolan
    Joined: Sep 2009
    Posts: 19
    Likes: 2, Points: 0, Legacy Rep: 51
    Location: Seattle

    Paul J. Nolan Junior Member

    The operative words in this sentence are "pretty" and "much." I submit a good name for a boat that is stable in pretty much all conditions is Black Swan.

    Paul
     
Forum posts represent the experience, opinion, and view of individual users. Boat Design Net does not necessarily endorse nor share the view of each individual post.
When making potentially dangerous or financial decisions, always employ and consult appropriate professionals. Your circumstances or experience may be different.