Guest jeff t Posted October 30, 2002 Report Share Posted October 30, 2002 Is there something other than plywood that dingies can be made from - something like an epoxy-glass-foam sandwich that can be bought? none@none.com Quote Link to comment Share on other sites More sharing options...
Guest Brad Whitehurst Posted October 30, 2002 Report Share Posted October 30, 2002 I'm sure there are all synthetic composite panels, but likely you would pay a fortune for them, and wood makes one of the best composite hull materials anyway, at least from a mechanical properties standpoint. That said, I do know of one person, Todd Dunn, who hangs out on the Cruising World B&B who designed and built a Blue Foam Dinghy (BFD!). He used the rigid blue foam you can get at Home Depot and epoxy/fiberglass as the skin. I imagine there would be even more fairing and sanding to get a good finish surface than with plywood or wood construction. Quote Link to comment Share on other sites More sharing options...
Guest Charlie Jones, Lotsa boat Posted October 31, 2002 Report Share Posted October 31, 2002 Blue Foam Dinghy. He kept telling us he was going to finish the site with more pictures but never did. He did complete the dinghy and has used it to get back and forth to his boat. http://www.geocities.com/TheTropics/8005/bfd/bfd.htm Mbdolfns@nospamtisd.net Quote Link to comment Share on other sites More sharing options...
Guest Frank Hagan, Weekender, O Posted October 31, 2002 Report Share Posted October 31, 2002 Plywood is still a miracle, in my eyes; strong in its own right, then stronger when flexed and glassed. Its amazing. I think you could probably use the foam core material that has wood veneers on it (Graham or Charlie probably know what its called or perhaps have used it.) Its usually used for larger boats but I suppose you could use it over a set of frames and glass it inside and out. Still, a lot of trouble to go through for a small boat. fshagan@ev1.net Quote Link to comment Share on other sites More sharing options...
Guest Charlie Jones, Lotsa boat Posted October 31, 2002 Report Share Posted October 31, 2002 which is a balsa center with veneers on both sides. Comes in strips so you can use it somewhat like strip planking. Can't recall the name of the foam stuff. Costly though, especially for a dink. Shipping would add tremendously to the cost of a small boat I think. I agree on the plywood. With the coming of epoxies, plywood has taken on an entire new nature in boat building from the days back in the late 50s -early 60's when it got such a bad reputation. And now we have the plys from abroad - the Okumes, etc. Whole different world now. Mbdolfns@nospamtisd.net Quote Link to comment Share on other sites More sharing options...
Guest Graham Byrnes Posted October 31, 2002 Report Share Posted October 31, 2002 Yes, plywood and epoxy is the wonder material. For example, fiberglass weighs roughly 3 times what okume of equal thickness weighs. If you were building a Spindrift out of fiberglass to weigh the same as 1/4" ply, it would have to be 1/12" thick, which is just not stiff enough. When you build the glass hull thick enough for the stiffness it is too heavy, but it has excess tensile strength. If you removed the middle 1/3 of the fiberglass skin and put in some lightweight core material you would have a better match of stiffness, tensile strength and weight. If you engineered the sandwich very carefully you could almost match 1/4" plywood but it would cost more and you would still have to manufacture the sheet. Re: core materials. Several items in various strings have mentioned "cheap", "available at hardware" type materials - such as blueboard (styrofoam). Ahhhh that this were true - we would all be using it! Lets look at this material - as an example: The blueboard weighs about 2# per cu. ft. which is light indeed - so far so good...and it IS cheap (compared to ply). A Spindrift hull built out of 1" thick blue board with say, 12 oz of glass on either side, would have a nice light and stiff hull. BUT - on impact the blue board is not strong enough - in no time you would have boat that looked like it had gone through WWIII. And one of the by-products of having it be stiff enough, you transfer the loads to the interface of the foam and fiberglass skin. This causes the cells to shear. In other words, blueboard was not intended to be used in this structural manner. This is why boat building foams start at around 5# per Cu. ft. and have carefully engineered cell structures - which is why they cost so much - more than marine plywood! Also, you can not bend premade sandwich sheets into "boat" shapes. There is a place for cores in larger vessels...but for small boats what you'd end up with, in essence, is More Money, More Work! And besides wood is much prettier. Quote Link to comment Share on other sites More sharing options...
Guest Steve Tyree Posted June 19, 2003 Report Share Posted June 19, 2003 Well, I've been plundering this site for info on B&B boats and boatbuilding in general over the last few days. What a wealth of information, particularly from our erstwhile benefactor, Graham Byrnes. Many thanks to you and to all. I've often wondered about the viability of building a plywood boat out of foam, then glassing it inside and out. It looks as if I need wonder no longer! Quote Link to comment Share on other sites More sharing options...
Bill Heil Posted June 23, 2003 Report Share Posted June 23, 2003 if you want a cheaper, but seviceable boat, use 1/4" exterior fir or pine plywood. It is strong, uses waterproof glue and the stuff I have used in the last few years is remarkably free of voids. Now, the problem with it is that if it is only coated with epoxy, over time it will check and split the epoxy surface and let water in. So to have a good exterior surface, you need to glass it, which increases the weight. Fir is already heavier than okume. BUT, it is a lot cheaper and if your were going to build a beater boat, or if you were just experimenting, it is a good way to go. Bill Quote Link to comment Share on other sites More sharing options...
John Burritt Posted June 23, 2003 Report Share Posted June 23, 2003 This is another case of you get what you pay for. Building a boat out of pine or fir plywood is no easier than using okoume. Why not, for a bit more money, end up with a boat that will look good for a long time? Besides, you'll end up with a lighter boat because you don't have to glass it. Quote Link to comment Share on other sites More sharing options...
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