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sailFar.net  |  People, Boats, and Stories  |  Boat Discussion  |  Topic: Hull form, Keel and rudder design... merits and hazzards. « previous next »
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Author Topic: Hull form, Keel and rudder design... merits and hazzards.  (Read 4430 times)
skylark
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« Reply #40 on: February 04, 2010, 05:47:06 PM »

Thank you for this link.  Roger Taylor also has some interesting youtube videos.  I really like the concept of his boat, he stays in the cabin all of the time and rarely is in the cockpit when at sea.  The boat is set up to be sailed from inside the cabin.
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Paul
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« Reply #41 on: February 04, 2010, 06:30:57 PM »

I too like Roger Taylor's "unconventional" thinking and agree on some more than other. The idea of hardly ever leaving the cabin would for me take a lot of the fun away but then I haven't spent as many years getting cold and wet as Mr Taylor. I do very much like his idea of making his boat unsinkable but I think filling half the cabin with foam to achieve positive buoyancy when swamped only works on small boats with a special purpose. A more realistic approach is James Baldwins idea http://atomvoyages.com/projects/UnsinkableBoat.htm to make every storagelocker and compartment of his boat into a watertight compartment which will contain a leak or hullbreach to a small part of the hull adding maybe hours of repairtime before sinking. I find this so logical that I am astonished that it is not common practice to do this with at least the V-berth.
Have any of you done something similar?     

By the way, thanks for the grog! Smiley
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AdriftAtSea
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« Reply #42 on: February 17, 2010, 08:55:23 AM »

Nicely said... grog to ya for it. Smiley
Computer modeling, whether it's the weather, structural engineering, aeronautical engineering, fluid dynamics or whatever, is only as good as the person doing the modeling using the computer as a TOOL.

Therein lies much of the problem that many "lay" people don't appreciate.  There are a TON of people using computers tools that DO NOT understand the models or how to apply them.  So, they run a model, the computer spits out a number or a pretty picture and blammo...the number or picture gets reported/use/quoted/debunked.

I'll give a little case history from just a couple of weeks ago.  I was contacted by a client to do some modeling of something that is VERY dangerous and could have life-ending consequences for both my client and INNOCENT bystanders.

In my reply, I cautioned the client that ANY results we get from our models MUST be thoroughly and carefully tested with real-world, hands-on engineering tests.  The modeling results can guide the process, but it's NOT a 'model this, and go into production' type solution.  The potential costs are too high.

He absolutely agreed and was already thinking on that page.  I like to work with professionals that understand this sort of thing, and only felt compelled to mention it because all too often, the prospective client does NOT appreciate this.

Would you 'ask' a circular saw to build a house?  No, of course not.  Nor should one entrust the results of a computer model, which are nothing but numerical calculations, to provide a solution to a contextual problem.  The computer is only calculating numbers based on the equations it is programmed to use and only using the base data it is given.

Back to the topic at hand....the ONLY conclusion that can/should be drawn by ANY scientist or engineer using modeling is "this model says that cannot be done."  He SHOULD understand that the model could be limited (on purpose) or flawed.  The discussion should then go into "why might this model suggest that" and the thinking, problem solving HUMAN BEING should evaluate the results.

So, yes, there are many cases where a model says something cannot happen (or happens differently than reality).  That's often not the fault of the model itself or theory upon which it is based.  Rather, it is either (a) the fault of the USER applying a model in an incorrect context or (b) there is something unknown that the model is not taking into account.

Further, that's how models are improved...just like any other science, it is the FAILURES that teach you more than the successes.

Just some near-random thoughts from a dude who does the following professionally:

Quantum Chemistry Modeling
Molecular Dynamics Modeling
Computational Fluid Dynamics
Reactive Flow (Detonation) Modeling
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Captain Smollett
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« Reply #43 on: April 27, 2011, 10:00:44 AM »

Sometimes, the hull form is such an integral part of the boat's safety and the shape plays into stability in ways we often forget.  Too many times, we associate the stability of the boat coming from ballast, keel shape or some combination.

What about when a ballasted boat loose her keel completely?  Can the boat remain upright?  This happened to an Alberg 30 (lightning and age damaged keel bolts failed).

Quote

... the boat rolled completely from one side to other every ten
seconds. There was no longer anything counter-balancing the force of the mast. It felt
like rounding the Horn on a windjammer. It was a startling demonstration of Carl
Alberg?s genius. For her lines, her beautiful lines would capture and hold her right
there at the edge of the roll, and come back despite the fact that she was so badly
crippled.




(emphasis added)

I would be VERY interested to read about 'keel failure stability' of modern  (post CCA era) designs.
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Twenty years from now you will be more disappointed by the things that you didn't do than by the ones you did do. So throw off the bowlines. Sail away from the safe harbor. Catch the trade winds in your sails. Explore. Dream. Discover.  -Mark Twain
CharlieJ
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« Reply #44 on: April 27, 2011, 10:21:36 AM »

I got the new ports I installed in our previous boat from a Catalina 30, that lost it's keel off Matagorda Island. The boat washed ashore and other than parts salvage, was a total loss. They burned the hull and deck, since there was no way to get any kind of tow vehicles or trailers down that 12 miles of virgin beach.

I happen to have the masthead fitting, if anyone is interested.
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Charlie J
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