The use of computers in boat design

Discussion in 'General Computing' started by Stumble, Aug 12, 2011.

  1. Stumble
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    Stumble Senior Member

    Bataan,

    I don't think for a moment that you have to use a computer, or tank test a design in order to be confident that it will work the way it was intended when the boat was launched. My point was that by using traditional methods even the best designer is limited in the number of permutations that they can test, tank testing is still the gold standard in pre-construction testing, but computer simulation is getting better and better, and your contention that the old ways were better is just wrong.

    There are reasons that every designer I know, on everything from small dingoes to oil tankers use CAD programs of one sort or another. It isn't just personal preference, or no one would have made the switch in the first place. It is the fact that when used properly computers allow a designer to do things he otherwise couldn't at a speed and price that is cheaper than traditional modeling , testing, and design.

    The reality is just because something is traditional doesn't mean it is better ( or worse for that matter), all it means is that it was the best that was available at the time. To put forth the idea that a modern designer couldn't do what someone did at the turn of the century is laughable, and an insult to the people working in the field. For good or ill it is possible to buy a production boat today that is faster than the world record was in the 50's. This goes for both power and sail, and the difference between boats across the eras holds true using any metric you care to pick.

    I would go so far as to posit that a modern cruising boat, that I think we can agree looks more like a floating condo, than a boat really should. Is still more seaworth with better performance than even a fast ship of the line from the 1800's. All of this is a result of the tools that designers have today that just weren't available years ago. And reactionary distain on modern methods in favor of a romanticized view of tradition is silly. Yes there are modern designs that were colossal disaster, or mistakes, but the percentage relative to the number launched is much smaller.

    Just by comparison...

    USS Constitution a heavy frigate at over 200 foot long has clocked an impressive top speed of 13kn. My Olson 30 sailing short handed last weekend hit 12. And I can go upwind.
     
  2. braumab
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    braumab New Member

    Interesting post. You're right .. Computers and Tank Tests probably aren't needed but I also know that they at least speed the process up if you're trained on the software. I guess it's really just a matter of preference.
     
  3. BATAAN
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    BATAAN Senior Member

    USS Constitution was a specialty warship that carried enough heavy artillery to destroy a town, which it did several times, six months stores and ammo and several hundred men at the time it was doing 13 knots, while your Olson 30 is easily overloaded with 2 weeks stores alone let without the 44 guns at two tons each and I would hesitate to take it into real weather exposure, like Cape Horn or Cape of Good Hope while so loaded. I think you're comparing apples to cotton candy here.
    --
    To state that a modern cruising boat is more seaworthy with better performance than 'even a fast ship of the line' shows absolute ignorance of past ships (a ship of the line isn't designed for going fast, it's a heavily armed Naval war tank so of course you have better performance without all those cannons and two foot thick oak sides) and the capabilities, techniques and history of the art you wish to master.
    No, the modern cruising boat is not always more seaworthy, usually less so, and get some sea time in various big square rigged craft so you can learn the lesson yourself about the filthy weather and conditions they will use to the max to cover ground before you bad mouth things you so obviously know nothing about. Seemingly crude 1790 LADY WASHINGTON here is barely reefing topsails with a dry deck and going well to windward when the small boat is absolutely unable to do so, is overwhelmed and running off under bare poles. Don't say it's not true because I've been on the topsail yard reefing and watching the small boats get blown flat. Traditional ships are far far better at doing their job than most modern sailors realize.
    An Olson 30 is fun and pretty fast, and I know they are single-handed in the Pacific Cup and other fair weather races. I'd never call it a particularly good all-around boat for anything at all besides racing or race-cruising in good weather with the cargo of a credit card, even if a computer was used to figure it out.
     

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  4. PAR
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    PAR Yacht Designer/Builder

    I've found computers are fast at regurgitation and computation, but actually slower in conceptual aspects and some "shaping" requirements. Where computers really shine is correcting error, charge backs or other changes. In the old days, you had to carefully erase entire sections and redraw them, but now, you can just make a change and print out a new, revised sheet. This is where they really earn their keep. Fast hydrostatics is handy too.

    There's a reason they build two or more A/C boats for each team. One is the mule and full of ideas, while the other is full of different ideas. The two compete against each other and the best of the ideas eventually are incorporated into one contender. 10+ million each, but this is faster and actually much cheaper, then developing software to account for all the variables in a reliable fashion!
     
  5. BATAAN
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    BATAAN Senior Member

    Thanks PAR, it's always best to hear from a working pro who actually uses a tool daily. The obvious asset of being able to quickly change and produce a new drawing makes up for anything else that might annoy.
    And the fact that A/Cuppers just go ahead and make full-size trial models to find what actually works is nice to hear, especially the faster and much cheaper part. In film, audiences are all talking how 'everything' is digital. Well, it isn't. Shapes like monsters and giant robots are developed as large scale maquettes first out of clay, then changed and changed again. When they are right, they are scanned and the digital animation begins. It's much much cheaper this way. The enclosed shot shows us trying to incorporate a small scale rig onto a full scale ship set which had no rig for P1. The computer puts it all together but cannot create it.
    The schooner dried out along side the wharf here is a typical 1880s English coaster that carried everything from bricks to oats, 100 tons at a time. She was probably designed from a half model by a man who could hardly read but understood geometry and shapes well, yet did her job and just kept doing it summer and winter, year after year, with no power or electricity of any kind aboard except 'armstrong's patent'. Crude, dangerous, requiring skill in operation yes, but inefficient or money losing it was not.
     

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  6. PAR
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    PAR Yacht Designer/Builder

    I will add that Bataan's continued reference to fine old working craft is forgetting one very important consideration; which is they often took the lives of their crews. In the beginning of the 20th century the transition to engineered structures based on reasonable and justifiable mathematics and sound physical principles started in earnest. This quickly bore out in the high end racing machines and more importantly the large commercial craft of the day. Previous to this all sorts of "slight of hand" was preformed to justify a design's particular attributes, some with deadly results.

    For example, when the skipper of Titanic raced across the north Atlantic, seemingly on a death wish, he was justified. Yep, this master seaman had an entire career in large steam ships and in his long, luxurious run, never was there an incident, remotely close to what he was about to experience. Gone where the days when stability was just guessed at and the designer held his breath on launch day. "Modern" ships where just too well engineered for this any more. For the most part he was right too.

    Previous to this and to which I'm speaking, the old working vessels where notorious for killing crew and skippers. Some of this can be accounted to the lack of accurate weather forecasting, but much of it is the dangerous ships they trusted. An example is the trust placed in some of these so called "well founded" ships that got reproduced and killed crew, just like they did back in the early 1800's from which it was copied. The first Pride of Baltimore is a perfect example of this. Chasseur was the vessel it was patterned after, in 1975 when commissioned, but sure enough knocked to her beam ends in a micro burst with the lose of 4, two of which I knew in 1986. Once a new, replacement vessel was considered, a long look at the former revealed huge issues and the Pride of Baltimore II is considerably modernized as a result.

    I make this comment often about folks wanting to build "antique" vessels, maybe from plans seen in some book or the Smithsonian collection. Be careful what you wish for, as these craft aren't remotely what a modern sailor wants to deal with, nor have the sailing skills to match.

    I guess what I'm trying to say is, though they may be pretty, they also usually have major issues, which at the time of their conception may not have been known, fully understood or considered relevant. The average person looking for an "antique" vessel of some sort would be best advised to have a "in the tradition of" built, rather then the real thing. They'll be safer, it'll be cheaper to build, likely preform better and you (depending on type) will likely recover from a "spreaders in the drink" situation, rather then die, like the brave lads of yore did.
     
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  7. jak3b
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    jak3b Junior Member

    I knew several fisherman who died at sea on modern steel commercial boats.They die every year from Gloucester, New Bedford, Seattle.Boats are still lost.I look at old photographs of San Francisco especially, and you see a sea of masts along the water front.Or Gloucester Harbor at the turn of the 20th century.There are hundreds of sailing vessels of all description in the harbor.There were lots more vessels working then than now.Not many people had yachts.It was for the very rich.Now its reversed.The number of pleasure boats far out numbers commercial vessels.its a rare thing to see a coastal freighter at all these days because of trucking, rail and air transport is so much faster.Most of the loss of life at sea happend in the fishing industry.They fished year round.It was and still is very dangerous.If you took the volvo ocean racers,orma 60 tris,TP52s and forced them to sail through the winter on the grand banks I bet lots of those lads would never return either.Ive sailed my whole life.Most of it on modern fiberglass racer/cruiser type sailing vessels.Sloops,CCA and IOR derived designs.I had the pleasure of cruising on 2 diiferent friendship sloops,One of them was built by Wilber Morse in 1912.I have to say they were much easier to sail then the modern boats in alot of respects,and in some cases faster.The main thing was that they were much easier on the body. The motion was much less tiring.I was at first intimidated by the huge mainsail, but it really wasnt any harder to deal with.Its just a different style of sailing.Now, Im not sailing year round, what ever the weather.I sail for pleasure not to eek out a living.My time on the ocean is miniscule compared to any lobsterman.
     
  8. BATAAN
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    BATAAN Senior Member

    Pride of Baltimore was a pretty exact copy of a specialized cheap vessel expressly designed to go very well in light to moderate weather and engage in illegal trades, and not a general purpose all weather working ship such as I have been discussing. She had sharp lines and inside ballast, not a good combination for stability as the shape keeps the ballast high.
    The original Baltimore Clippers were built in a few weeks, of green wood to extreme lines to make a huge profit quickly. POB's low freeboard, lack of bulkheads and very tall heavy rig were how these cheap disposable blockade runners, privateers and slavers were built as they followed dangerous trades and had often short lives, measured in weeks, that had nothing to do with the dangers of the sea, but had to sail fast to get away from war ships and chase slower merchantmen.
    I sailed many months on CALIFORNIAN, a 90' topsail schooner, with two of the crew who were on Pride when she sank and they are my large-traditional-gaff-schooner-owning neighbors today, so I got a first hand account of the accident, and sailing her in heavy conditions was described as 'riding a wild wet horse that had the bit in its teeth'.
    These were seen as unusually unsafe vessels when they were built about the time of the war of 1812 and the copy had all the vices of the original, including no watertight bulkheads. When she capsized in the microburst the wind held her down, she put the large open companionway hatch in the water and filled, righted, and sank, all in 3 minutes and by the time she went under the wind was almost calm. Bulkheads, outside ballast, a smaller rig and more freeboard make her replacement a more seaworthy and much safer ship.
    I have not forgotten the dangers that the early sailors faced but those were mostly involving primitive navigation methods and weather prediction, not poor vessel designs.
    Navigating any ship, old or modern, with no engine around the coasts or the world loaded with cargo, without Radar, GPS, depth sounder or the highly detailed charts we use, is asking for occasional disaster that has little to do with vessel design with the exception of being able to beat off a lee shore, the trap waiting for any sailor, which a stiff weatherly vessel does best.
    According to actual records, and not vague yachting folklore, much of the death of crews in the bad old days was due to the criminal negligence of owners as far as maintenance. When a sailor went aboard a ship the first thing he looked at were the hand pumps, and if they were bright with use and well-worn, he turned right around and went back on the wharf and looked for a ship with dusty, unused ones. When working at Mystic I read many antique logs and accounts as part of my job, and was amazed at what the old guys did with their ships. Whalers routinely spent winters in the arctic, hunted in the antarctic, and explored the polar regions for years at a time. Sealers of the 1880s took grossly overloaded sharp 70' schooners (10" freeboard) to the Siberian Arctic for fur seal time and time again. The world crawled with working sailing craft in every navigable corner because there was a profit to be made. There were lots of accidents because there were lots and lots and lots of ships, few nav aids and intense economic pressure to take chances. Here are some photos from my research library of typical fleets of coasters, one waiting for a wind change, the other taking advantage of one. The last is the 65' JOHANN CARL sailing into Newquay in Cornwall, and you can see the danger doesn't have much to do with the vessel, which is low on her marks with a paying cargo.
    Few old working designs make acceptable modern yachts, but some designers manage to blend pilot boat traditions with today's engineering.
    Here are two modern boats from Ed Burnett, who has often partnered with Nigel Irens in the past. These are steel for the brigantine and cold molded for the cutter, with of course very light modern spars and rig.
    Lovely, weatherly, long lasting and very very expensive per pound, unlike the working boats we have been talking about. BERTIE was about $3 per pound but one of these would be more like $12-$15, like any equivalent from a modern architect. You pays yer money and takes yer choice. For many of us it's a very cheap boat or no boat, so fancy theory of design means little. I once built a simplified, smaller (32') SPRAY for a client for $5000. Lapstrake, copper and bronze fastened, no engine. This is what a set of mediocre sails costs for a typical 32 footer.....
     

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  9. PAR
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    PAR Yacht Designer/Builder

    I'm not picking on you Bataan and I'm not talking about "interpretations" of old ships or yachts, but the actual puppies themselves. Ed's 77' brigantine is a perfect example of an interpretation and precisely what I'm talking about. If that 77'er was an example of a 1805 build, it would have twice the sail area and all internal ballast, likely stones. Ed's brigantine, on the other hand has a 13.5 SA/D ratio on a very modest 233 D/L and an impressive AVS, which is nothing remotely close to what would have been the case a couple of hundred years ago. Ed has done a nice job (typical for him) in making a stable platform look a couple of hundred years old, while incorporating the knowledge of design evolution these last two centuries have brought.

    In small craft we hear about the wonderful sailing qualities of the dory, but if you've actually ever sailed a real, 150 year old dory, it's a skittish, tender witch, until it has a ton of fish in it's belly. This is my point, most have no idea what these old design handle like. I've sailed real 100 year old log canoes, big topsail reproductions and actual survivors of many different classes. Most are something you don't want to own, but are lovely to look at and watch other people capsize in (on a warm day).

    When 50% of a fishing fleet doesn't return and they adopt a new hull design 10 years later, you can pretty much assure yourself, the design was flawed and killed a lot of fishermen before they realized it.

    We do agree in that there are many factors involving working craft, as far as the death of crews, but lousy design also played a fair role as well. Yes, owners and builders were trying to make money and crew safety wasn't a high priority and yes, many ships were run by drunken task masters with little regard, but then I'm reminded of how the Gloucester sloop boat came to be. They were using smacks on the rock ledges and in near shore fisheries, but ventured further and further off shore. Eventually they started to lose boats and crews at an alarming rate. It took them years to figure this out and develop the boat we now know as the Gloucester sloop, which was much better suited to deep water.

    Admittedly, they didn't have the luxury of data bases we have today. They didn't have the infrastructure nor anyone other then their wives and owners to give a damn about what was happening, let alone the common sense to put two and two together. In fact, it was these loses that forced more active participation and records keeping, tough also admittedly for a very long time it was "just the cost of doing business" to most.

    Again my point is take care what you wish for. I just acquired a 65' production boat. It easily covers 320 to 350 miles a day and nearly 500 miles if WOT under power! No, it doesn't look like Clark Gable might have done a movie on her once, quite the opposite, but she was cheap and I stole her from a desperate owner. Hell, I wasn't even looking for a boat like this, but now I got it and will be able to upgrade the crap out of her and turn her over. She has a 54% ballast ratio, a ridiculous SA/D and mid 50's D/L. Nope, not especially comfortable in a rough slosh to windward (okay anything to windward), but she'll easily out pace any "antique" by a factor of 2 or 3, not to mention out point them by 20 degrees. This is what modern thinking brings to the table and you can have most of it in a "spirit of" style of design, which BTW is precisely what that brigantine of Ed's is.
     
  10. Lister

    Lister Previous Member

    I edited.

    You just bought the worst possible boat for blue water cruising.
    The best boat for round the buoy racing.
    Modern thinking is just a marketing view. The sea doesn't care about it.
    Different boat for different purpose. This is the reality.
    What the Frers and other boat designer try to sell, is pure indifference to the customer, it is just a copy of the automobile attitude: every one the same car. But road doesn't have stormy waves capsizing the car.
    Frers and other genius should think about that.
    Lister
     
  11. BATAAN
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    BATAAN Senior Member

    Being a Mystic trained rigger and having spent the last 40 years in the wooden boat business plus working as a historian (not the book kind) for various museums, I've sailed extensively most available historic types from L.A. DUNTON's fishing dories on the Mystic River to several weeks on HM Bark ENDEAVOUR, the 1769 reproduction of Cook's ship, off the west coast of BC, big topsail schooners like CALIFORNIAN and LYNX, a couple of Friendship sloops on long passages and many more. I probably have more sea time on traditional types than most sailors and started in 1969 when I got out of the CG.
    Dories suck as sailboats, they're rowing fishing craft meant to nest and stack on a Gloucesterman's deck, and even the yacht racing types are poor compromises. ENDEAVOUR is extremely antique, short, tubby, square rig, not too fast, but is 400 tons capacity, goes to windward amazingly well, is one of the most seaworthy types ever built (did a Tasmania, Cape Horn, Whitby UK voyage a few years back) and educated me on what a comfortable safe ship was. Cook bought the original out of the Whitby collier fleet because he knew there was no better exploration vessel for the times and his voyages on her and others of her type, and those of Vancouver in the same, were once well known.
    The following is an example of vague yachting folklore and the confusion that results. You mention 'smacks' with no definition (east coast American 'smack' is a decked wet-well sloop, 30 to 60 feet, usually from Noank, like the EMMA C. BERRY at Mystic which is the only surviving example), but I think you may be referring to the extremely wide and shallow Gloucester fishing schooners that were very fast and dangerous in the 1870s and 80s and killed their crews wholesale from capsizes when being driven hard to market. This developed the modern Gloucesterman as a result, with much input from yacht designers like Crowninshield. See "The American Fishing Schooners 1825-1935" by Chapelle for in depth details of this design progression.
    The sloop was always around since the beginning of building at Essex in the 1600s and every model of Essex-built (Gloucester) schooner had its equivalent smaller sloop for those who couldn't afford a schooner, and they worked the closer fisheries mostly instead of going to the banks for cod. They were never called Gloucester sloops until the media started touting them for yacht conversions in the 20s. At Essex and Gloucester they were "sloop bo'ts" and common as dirt.
    The subject of fishing vessels always gets brought up, but the fleets in the photos above in my previous post are all small cargo ships and are a different animal and not to be compared to fishermen or yachts.
    It's easy to compare a modern 65' fiberglass production yacht that will cover 300+ miles a day carrying very little but food and water, to a schooner or ketch or cutter rigged coaster that carries 100 tons of coal for a profit and covers 50-100 miles a day in the extremely rough and tidal Bristol Channel working around strong and fickle currents and winds, but they are different things, as unalike as a Ferrari and a semi-truck, and do completely different jobs, so shouldn't be compared any more than the wheeled equivalents.
    Ed's brigantine falls in the Ferrari camp, as it's a yacht with no useful load beyond passengers. When you put 100 tons in the production 65 footer, then we can compare them honestly.
    The coaster skipper has to load his 100 ton cargo while aground up some creek next to a coal chute and trim it out with his crew of 3, work out the creek with no engine by using current and anchors, sail several hundred miles of Irish Sea or the western approaches, find her delivery port which may be a beach exposed to the western Atlantic with no marks or lights at all, go aground at high tide and sit upright, unload into carts when the tide ebbs, then leave on the next flood and do it all over again. Some of these little ships did this for 75 years before being lost through accident or being scrapped, so fit my definition of extremely good boats because they were designed by the needs of their trade and did that trade very well.
    Here are photos of the beach traders at work. Notice the ketch being towed out the narrow rocky entrance by the oared boat just visible under her bowsprit.
     

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  12. Tad
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    Tad Boat Designer

    I think there are enough bad performing unsafe modern boats around for all to realize that the use of computer design means nothing when looking at design quality. A computer is not required to design a good boat, and computer use does not automatically guarantee a superior design.....advertizing copy to the contrary.....

    There are lots of reasons for increased use of computers in design, one of them is the huge change in what builders expect from the designer. In years gone by (not that long ago) a "design" for a 40' powerboat might consist of 4 drawings; (1)Lines and offsets, (2)Profile and arrangement, (3)General construction, (4)Construction sections. Design hours would be 80-100. Drawings were done in pencil (and perhaps traced in ink) and were difficult to revise. The builder did the lofting, and could be trusted to sort the details and buy the correct equipment and install it properly. Today builders of a 40' expect a dozen sheets at least, plus full size plots, plus surfaces for NC cutting the plug, plus engineering to some standard, powering studies, elaborate weight and stability studies, etc. And they don't expect to pay the designer a great deal more than they did 20 years ago. Today's 40' might have 4-600 design hours.....and everybody wants stuff done instantly though initial drawing in CAD is always slower (for me) than hand drawing.

    But with the computer revisions and importing pieces of previous drawings is quick, and exchange of information with equipment suppliers, yards or other designers is instant....3D modeling is a wonderful tool that eliminates (for me) the half or full physical model building step. I used to hate the rigamarole I would go through to get a scale drawing of an engine with the right gear on it....phone calls/faxes/waiting, then endless photocopy work....and it was never quite right....now I zoom to the manufacturers site, download a dxf, and plunk it in the drawing...2 minutes or less......that's nice.....
     
  13. BATAAN
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    BATAAN Senior Member

    Tad, thanks for putting things in economic perspective. The computer seems to make the difficult easy and the customer happy, and probably gives a better and more thoroughly worked-out boat with many more calcs than were formerly used.
     
  14. BATAAN
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    BATAAN Senior Member

    I want to point out one place that computers are essential in boat design and build these days, and that is in plywood kits and manufactured boats. Here in PT most of the actual producing boatbuilders are long-bankrupt, though repair is brisk. It seems the only actual wooden boatbuilders that have a going business these days use a computer as a really basic tool, and not an accessory, to design these vessels and to operate the laser cutters and CAD aided routers that cut the kits to very precise and repeatable patterns.
    This would be nearly impossible with people doing the same job unless production rate was very slow.
    Here is the really outstandingly good PT skiff and a Pygmy Kayak kit.
    So, an absolutely essential tool that has made some businesses viable.
     

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  15. gonzo
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    gonzo Senior Member

    There is no computer program in existence that can do what my drafting battens do. All programs limit the designs to series of curves. My sticks do what I want them to do and not what a computer programmer allows. Computer programmers seem to know little of boats and even less of aesthetics. I believe that is the reason there are so many ugly boats nowadays.
     
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