outrigger canoe lamination schedule

[drewke07]

I have completed the mold for a 24' outrigger canoe hull that I intend to make into a sailing double canoe. I am planning to use thermoform 10mm corecell as the core ( I have foam and epoxy left over from another project) and have not yet decided upon the lam schedule. Weight is of the utmost importance. Any advice on redily available carbon and/or kevlar reenforcements? I am thinking about 5.8oz carbon twill inside and out with an additional layer of 5.5oz kevlar on the outside. Is this too light? should I bulk it up with some glass cloth?

[Chris Ostlind]

Hi Drewke,

Could you give further explanation as to your thinking on the use of Kevlar on the outside of the lay-up schedule?

Making routine, cosmetic repairs to a hull with Kevlar cloth on the exterior is a real pain in the butt.

Weight is a typical concern for any multihull if you wish to extract the potential performance that should be available. Unless you plan to see some pretty rugged conditions in which impact protection will be one of the top concerns (Something like an expedition to a wild environment where rescue could be a long way away comes to mind here) I would suggest that you'll be much happier with a well designed glass lay-up instead.

If I did use Kevlar on a design that needed the extra protection, I'd put it under a couple of layers of glass if on the outside. My preference for this material in a laminate is putting the Kevlar on the inside of the hull where repair issues are much less frequent and you can still get a level of puncture resistance if you encounter a sharp object.

Kevlar is not very good at absorbing load in compression and is terrific when placed in tension. Kevlar is also hydrophilic in nature and it will absorb and wick water into the laminate where it can do other mischief if exposed to the water outside the hull.

Ask around about the issues associated with repairing Kevlar lay-ups compared to doing a similar job on a glass laminate. Kevlar can be a really good product if used correctly, but I think you'll find it extremely tedious when it comes time to do those commonplace repair jobs to which all boats are subjected.

Lastly... I'd really like to see your design for a double canoe as I'm sure others here would as well.

Chris

[drewke07]

Thanks Chris,

I am looking for a suggestion as to what the lam schedule should be. I am most comfortable using glass and my first inclination is to use 17oz biax eglass in and out. I am looking for a way to lighten her up. Kevlar may be more of a pain than it is worth, but I was looking for abraision resisitance for dragging her up on somewhat rocky beaches. Any suggestions?

[BWD]

A picture would really help. Or if no picture, the numbers: LWL BOA, hull BWL, Disp, Cp, etc.

Maybe most important, sail area and rig type and the displacement!

I am no NA but I think the amount of glass could vary by a factor of five or so depending on what kind of boat and use. Probably why no "answers" have been posted. Curious about the boat though, love to see a picture...