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#11
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Seaworthiness
"Peter Ward" wrote in message m... I guess I was thinking of seaworthiness in the fairly narrow sense of being able to survive something like 'The Perfect Storm'; & particularly the ability to quickly self-right in the event of capsize. According to Czeslaw A. Marchaj in 'Seaworthiness : The Forgotten Factor' the "point of vanishing stability" et.al. of most modern yacht designs is woefully inadequate - deficiencies he attributes to the pervasive influence of International Offshore Rules & the 'floating gin-palace' ethos of the charter-boat industry, on modern yacht design & construction. This observation appears to have been borne-out empirically by the 1988 Sydney to Hobart Yacht Race http://www.radford-yacht.com/stablty1.html In the Sydney-Hobart, the main lesson is don't get caught where the conditions are bad. The analysis showed that it didn't really matter what type of boat you were in - heavy narrow boats, light beamy ones, and everything in between got capsized.. But the boats in a certain area, the area with the worst conditions, were most likely to capsize. John Rousmaniere in his excellent book Fastnet Force Ten came to a somewhat similar conclusion about the Fastnet - that boats in a certain area were more likely to be capsized. That doesn't validate poor design, but it tells me that if you are in the wrong place at the wrong time, it doesn't matter what kind of boat you're in. Personally, Id recommend a boat with a limit of positive stability of greater than 120 degrees, with all the cruising gear included in the calculation (which is probably not the design condition). And make sure your boat is ISAF Category 1 or zero compliant. Design is one element of seaworthiness, but the crew (and luck) is equally or more important. Consider that the boat that won the 98 Sydney-Hobart was a light 35 footer that consistently does well in that race and you'll start to get a feeling that those guys could probably sail a crappy old raft through just about anything. And it sounds like you've read the books about the guys with no experience who cross oceans, so you can see the part that lady luck plays as well. More books that would probably be of interest to you: Heavy Weather Sailing has lots of good info, including chapters about desingn features. The Drag Device Data Book if you're really serious about going offshore. Fastnet Force 10. There's also a book about the Queen's Birthday Storm that hit a bunch of cruisers in the South Pacific, but I can't remember the name right now. As a natural pessimist, I want to build the 'ultimate-unsinkable' craft, which will weather the worst that the sea can inflict; however, I get the distinct impression leafing through all the myriad yachting magazines, that most boats out there are little more than flimsy eye-candy. Just another prettified escapist consumer commodity designed more to part you from your hard-earned lucre, than to be truly "worthy of the sea". Well, there are good boats and bad boats. There are quite a few seaworthy ones available for good prices. Some of them are lightweight flyers, and some are heavy tanks. It's hard to make a boat unsinkable but it is possible to minimize the probability. Watertight subdivision is one way to do it, but you will find that only the Amel boats come from the factory that way. Ramblin' Matt |
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#13
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Seaworthiness
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#14
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Seaworthiness
Rodney Myrvaagnes ) writes:
The most bedrock principle is the need for a capable crew. An archaic design may make you feel salty, but that isn't the same thing. That is the assessment I read of Joshua Slocam and Spray, an ordinary east coast lobster boat, and extrodinary sailor with a lifetime of ocean sailing experience. I think also luck since the life expectancy of sailors was low in his day. -- ------------------------------------------------------------------------------ William R Watt National Capital FreeNet Ottawa's free community network homepage: www.ncf.ca/~ag384/top.htm warning: non-freenet email must have "notspam" in subject or it's returned |
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#15
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Seaworthiness
"Peter Ward" wrote in message m... I guess I was thinking of seaworthiness in the fairly narrow sense of being able to survive something like 'The Perfect Storm'; If it's The Perfect Storm you want to survive then clearly you need a Westsail 32. A W32 DID survive the Perfect Storm. Unmanned no-less and, as far as I last heard is still sailing. Yet another Steve |
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#16
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Seaworthiness
Yes, but the Westsail 32 earned the sobriquet "WetSnail". A tough boat, but
not my first choice for anything. -- Jim Woodward www.mvFintry.com .. "Stephen Yoder" wrote in message thlink.net... "Peter Ward" wrote in message m... I guess I was thinking of seaworthiness in the fairly narrow sense of being able to survive something like 'The Perfect Storm'; If it's The Perfect Storm you want to survive then clearly you need a Westsail 32. A W32 DID survive the Perfect Storm. Unmanned no-less and, as far as I last heard is still sailing. Yet another Steve |
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#17
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Seaworthiness
"William R. Watt" wrote in message ... define "seaworthiness" I thought it meant a boat that would take care of itself in rough conditions, not a boat that could perhaps outrace the weather. This outracing the weather is only helpfull along the coast where, given advance warning of deteriorating weather conditions over the radio, the faster boat can run for cover. Its not much help mid ocean in a big weather system. Sorry to disagree but some years ago, during a westward Atlantic crossing, we became threatened by a tropical storm that later developed in a hurricane. My boat was fast enough to efficiently take the classic escape course from such a system. It was my fault to cross to early in season but the fast boat made all the difference and kept us safe, right in the middle of the ocean. -- Jacques http://www.bateau.com |
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#18
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Seaworthiness
Peter Ward wrote:
I guess I was thinking of seaworthiness in the fairly narrow sense of being able to survive something like 'The Perfect Storm'; & particularly the ability to quickly self-right in the event of capsize. According to Czeslaw A. Marchaj in 'Seaworthiness : The Forgotten Factor' the "point of vanishing stability" et.al. of most modern yacht designs is woefully inadequate There are some fairly simple ways to evaluate the relative stability of a sailboat, and there is a very wide range of boats on the market. To say 'modern yacht designs' have *any* single factor in common is like saying 'modern motor vehicles' are all thus-and-so. How about we say 'some popular modern yacht designs are woefully inadequate'? Then the trick is much simpler, just avoid these particular ones. As a natural pessimist, I want to build the 'ultimate-unsinkable' craft, which will weather the worst that the sea can inflict; As a natural pessimist myself, let me assure that such a thing does not exist. The ocean is incredibly powerful, it can tear up battleships & supertankers when it's in the mood to. The only answer for surviving such conditions in a small sailboat is.... be elsewhere.... That said, a high ballast displacement ratio and full positive flotation make a lot of sense for ocean passagemaking sailboats. "William R. Watt" wrote... define "seaworthiness" I thought it meant a boat that would take care of itself in rough conditions That is a good quality to have, but it can also include having the right gear such as a drogue and/or a storm staysail. .... not a boat that could perhaps outrace the weather. This outracing the weather is only helpfull along the coast where, given advance warning of deteriorating weather conditions over the radio, the faster boat can run for cover. Its not much help mid ocean in a big weather system. I disagree strongly. A boat that can make good miles, especially reaching or close reaching in a seaway, is going to spend a lot less time in a storm system and will be able to keep further away from the center. The main indicator of seaworthiness is the displacement to length ratio. Boats with a ratio over (I think) 300 are the most seaworthy. These are ocean going cruisers. Because boats are sold by the pound they are expensive. I know lighter materials can cost more per pound by they don't have as many pounds. The heavy cruisers also have more room for accomdation and storage and a better comfort factor. They can make good time under all conditions but light winds. And to windward, usually. The issue here is that a lot of the current generation like heavy heavy boats. Therefor, since so many of the boats out there cruising are heavyweights, the statistical evidence that heavy boats make the best cruisers is self perpetuating. Heavy boats are good at one thing.... not getting bounced around. Weight conveys no advantage beyond simple inertia. Jim Woodward wrote: Again, I point at Sayula II. Tough boat, but a whole lot faster than a Colin Archer. As for outracing the weather at sea, if I have a hurricane forecast in front of me, with pretty good track guesses from the NHC, I'd rather have a boat that was a modern, fast, tough, seaworthy design, rather than an old, slow, tough, seaworthy design. Not extreme, but taking into account modern design thinking. For example, there's some evidence that a modern keel and skeg design is less likely to "trip" on a wave and capsize, than the old full keel designs. Certainly modern designs with the rudder way aft have more steering leverage and therefore will steer better in extreme conditions than long keels with attached rudder. They will also respond better with less work by either helmsman or autopilot. A tired helmsman is a poor safety factor to have in big breaking seas. Swee****er (Swan 57) has a D/L of about 230. She certainly never gave us any concerns on our circumnav and I would believe she is sufficiently seaworthy for all "ordinary" purposes -- no Southern Ocean work, I think. A 230 D/L does not mean "weak" as a simple glance around at the scantlings of a Swan will show you. Further point, heavily built is not necessarily stronger. Polyester resin is brittle. In an early edition of his book on building the Westsail 32, Ferenc Mate advocated using resin & newspaper to block in parts of the hull. This is going to add zero strength. Lots of older boats with very thick hulls are actually weaker due to the use of short strand mat, chopper guns, lots of voids, cloth edges at odd points, etc etc. All else being equal, heavier is usually stronger. But 'all else' never is quite equal, and the strongest boats are the ones that are well engineered and properly built with suitable materials. This doesn't happen by accident. Fresh Breezes- Doug King |
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#19
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Seaworthiness
"Jacques Mertens" wrote in message ...
Yacht design and especially boat building materials have progressed since the designs you list. They may have been the best 100+ years ago but it's like saying that the Ford model T is the best car ever built! Point taken; however, I can't help but note that modern mathematicians are coming round to the view that the archaic 'oceanic lateen' sail design - developed by ancient Polynesians over 4,000 years ago - is actually more 'efficient' than the modern Bermudan. I would have thought it quite possible that the 'ye olde worlde' designers may well have hit upon the 'Platonic Ideal' of ultimate seaworthy hull design via the school of very hard knocks & near-death epiphanies. Try some books like "Seaworthiness" by Marchaj or check books by Dave Gerr. It is undeniable that the boats who rcae aorund the world today are more seaworth than a Colin Archer. I'm sure you're correct - but are they "more seaworthy" because of superior design or superior construction or a mix of both? I personally prefer this definition of seaworthy: "define "seaworthiness" I thought it meant a boat that would take care of itself in rough conditions, not a boat that could perhaps outrace the weather." [rom: William R. Watt ) Subject: Seaworthiness Newsgroups: rec.boats.building Date: 2003-11-10 13:50:05 PST ] Someone in an earlier post mentioned that the Westsail 32 is proven seaworthy by virtue of having actually survived 'The Perfect Storm' without human intervention ...so I do a quick google search & lo & behold up comes something which could be quite easily be mistaken for a Bristol Channel Pilot Cutter in a dark seaway & has a blue-blood Colin Archer pedigree to boot!!: http://www.boatus.com/jackhornor/sail/Westsail32.htm PS: a judgement about seaworthiness should not be based on fear of the sea . . . A very prescient observation. I don't mind admitting that I do in fact have a healthy fear of the sea ...& it is in fact the primary motivating factor in my quest for the *_most seaworthy_* design & construction available for a vessel under 35'. One of my formative late-life experiences was being caught on what the locals call a "crook crossing" of Bass Strait (Devonport Tas. to Melbourne Vic.) some years ago. I was on exactly the same type of ferry that foundered in the Baltic whilst crossing from Estonia to Sweden in 1994; it was a massive vessel of many thousands of tons displacement but literally being bounced & wracked like a balsa model in what looked very much like a watery version of Dante's Inferno. The only shared religious experience I've had in my entire life in fact. -- Jacques http://www.bateau.com "Peter Ward" wrote in message m... From random reading I've formed the impression that the Bristol Channel Pilot Cutter is the epitome of a seaworthy design. Colin Archer designs seem to get the big tick also. |
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#20
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Seaworthiness
Just to finish the story - the above-mentioned experience gave me a
quasi-mystical insight into the awesome power of the sea. For anyone who's never heard the obscene shrieking of triple screws unsheathed from the brine at full power for minutes at a time as a gargantuan vessel pitches, rolls & yaws simultaneously to the extremes of the envelope; followed by the thunderous explosion of a flat-face bow smashing into a bottomless trough at thousands of tonnes mass ...then loop the sequence for hours on end; it's probably difficult to conjure just what horrors the sea can deliver I now understand why coconuts-in-husk are probably the only *_truly seaworthy_* design. However the 'takeaway' from all of the exceptionally good advice on offer in this thread appears to be that 'seaworthiness is a multi-dimensional challenge' & preparing for the worst involves garnering a wide range of skills & resources ...including a first rate liferaft & epirb. If "fear of the sea" inspires one to take every precaution possible right from the getgo, in order that others will not have to put their lives at risk in order to extract one from what would otherwise be one's watery grave; then surely its not such a bad thing? |
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