Cold Molded Hull Strength?

Discussion in 'Materials' started by UNCIVILIZED, Jul 7, 2014.

    Joined: Jun 2014
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    Location: Land O' the Great Lakes

    UNCIVILIZED DIY Junkyard MadScientist

    Guys, THANKS for all of your answers & time. I'd never figured that this post would stir up such a fire storm (of good thoughts & feedback). Glad I posted the question.

    Eric, thanks for chiming in. I've always been a BIG fan of your work, just never had a reason to get in touch. But guys who can run their own office, build boats, and publish, until recently, were a rarely impressive thing in this business.
    That said I own an ancient E-copy of "... on Boat Construction", & a 25yr old hard copy of said text. Which I got not long after receiving my degree & Commission. Great book. And I steer lots of folks to all of the sites which you mentioned. Plus have lots of their publications around (too many). Ah, & lived in Port Townsend, WA for 15yrs, plus several stints in Newport (yes, both of'em).

    I've got more than plenty of background in boats & ships, including still recalling how to calculate Free Communication Effect. Plus how to apply any kind of goo in a tube sans gloves or shower cap, & most importantly Mess. That & the insanity which is Carbon Fiber cored with Aluminum Honeycomb - Though racing those boats was fun.
    And I've rebuilt a variety of boats, including some sweet multi's. One of which adopted me ;-)
    - not blowing my own horn, just trying to fill in the background questions -

    I was just posing the question about the Cold Molded thing as I've never seen it answered satisfactorily anywhere. And this seemed like a reasonable place to give it a shot. Knock on wood (no pun intended), I understand a lot of the pros & cons of the materials mentioned. However, now, with vacume bagging being so prevalent, Cold Molding's a lot more intriguing. A screw gun, Visquine, & a Shop Vac beat installing & pulling 100k staples any day in my book.

    As to what I'd like to build, I'm at the moment, undecided. I'd love a mid-sized catamaran, say 35' or a bit more. But don't want to spend 7yrs playing with epoxy & power tools.
    Wood's definitely going to play a big place in the build, regardless of type, me thinks.
    And if it weren't so danged labor intensive, Steve Rander's COVE system has had my attention for a LONG time. So have Kurt Hughes unique Cylinder Molding & vacume bagging techniques/styles of construction.
    [PS: Any links to info on the COVE system or boats built with it, aside from the issue in ProBoat would be appreciated. And, yep, been to/talked with the "source" on it. Especially if anyone's done say a wood/Plascore or Nidacore/wood build].

    So, in a mono, 40' max +/- & a bit smaller in a cat. The loads on things, & their attendant cost just seems to go real steep after that. Smaller would be nice, though I'd care to have a tiny bit of room for my personal junk on a boat. And this'd be a cruiser, ergo loads of spares, sails, etc.
    That said, after a bunch o' decades of racing, I'd go loco being stuck @ 4kts. Or as my old neighbor with a Colvin Gazelle said, when it's light, junkies drink!

    I don't see tools, or skills as a big problem. Besides, towards the end of things, if you bought quality tools, just sell'em & buy boat gear.
    As to the build shed, & the where... now that's an interesting one. Geometrically more so if I build a cat. The whole transporting a 25' wide boat thing & all.
    - So, hypothetically speaking... someplace warm, sans Hurricanes or winds close there to, close to the water, has good neighbors, & cheap rent.
    Joined: Jun 2014
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    Location: Land O' the Great Lakes

    UNCIVILIZED DIY Junkyard MadScientist

    PS: As to the quality of most current generation fiberglass boats, my personal opinion of most of'em is beyond low. 20 years ago when I looked inside the "chain locker" of a new production boat, & it's laminate was thinner than my shower stall at home... and I could see hard spots where each & every bulkhead was.
  3. ondarvr
    Joined: Dec 2005
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    Location: Monroe WA

    ondarvr Senior Member

    I always find it interesting when builders (craftsman/shipwright ) compare one-off specially built sailboats that have been planned for years and every detail agonized over for the best possible result. Then built by a crew that loves what they do and appreciate and understand the fine details and every nuance of the design. To a production crew that has never been on a boat, doesn't know the difference between an unlimited hydroplane and a Chinese Junk, and last week was fired from a landscaping job for not paying enough attention to detail (like don't mow over the roses).

    I see examples of both worlds frequently, boats built to a price point (lowest possible) and as quickly as they can be, to what many on this site loving create.
    While both float, they are built for totally different markets and purposes.
  4. discovery
    Joined: Aug 2013
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    Location: Australia

    discovery Junior Member

    Absolutely agree, sometimes for a hull / structure to yield a little (bend , conform ,ect ) may be perceived as weak because it bent / yielded yet the ability to yield some but maintain integrity is where it has its uses.

  5. Forestgnome
    Joined: Jul 2014
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    Location: Sacramento, CA

    Forestgnome New Member

    To have a real answer, you would need to use specified layup schedules to create test panels, then test each one according to the standard measures of strength ( If I remember correctly, the Gougeon book has some tables related to testing. Wood/glass laminates can be very impressive. I have a test panel of Baltek core laminate that impressed the heck out of me when compared to plywood. The major downside of wood laminates is of course water intrusion. Not as big of a problem in glass boats.
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