PK78 - Okume v. Marine Plywood / Fir

[jacquesmm]

We started discussing Okume versus Fir then drifted to the R13 then argued about scantlings. . .

It is possible to build very light boats by using 4 mm aircraft plywood at $ 120.00 a sheet. Other weight gains can be made with framed light ply for the top seats and foam sandwich seats and frames. Lightenings holes should be cut wherever possible.
It is all very costly and labor intensive. Until now, many have asked the questions and sometimes argued about it but not many have tried.

If one has problems believing our weights, he can refer to Tom Hill's book. Tom H. uses the same scantlings: 4 or 6 mm Okume.
He rates his 15' 9" Whisp at 68 lbs against 65 for our Row 13 in light version. The Whisp is almost 3' longer and has fancy woodwork.
He has a wide canoe looking like our Scilly Gig, same overall length and beam and announces 49.5 lbs, ours is 80 to 100 lbs and I know one builder who made one hitting the scale at 65 lbs.
Our weights are reasonable. When we announce a light weight version, we expect the builder to pick the best materials, understand that he needs lightening holes and show good skills in his fiberglass work like 50% glass content.
If a 1st time builder uses cheap materials and does a sloppy fiberglass job, he should not complain about the extra weight.
If you are a 1st time builder and want a light boat, build an heavy one 1st.
I am not joking, it is not easy to make a light and strong hull, it takes some experience and more $.

[JLL]

Thank you for ALL your responses. Regardless of other disagreements, the answer to my question is clear. I will build the boat from Okume. Any savings from using another type of wood are dwarfed by my time and labor input. I believe in doing it right the first time. I will order the Okume Plywood.

I've already built that first boat. It was very heavy and I hope I learned my lessons.

Thank you again for all your help, and I'm sure I'll have more questions!

JLL

[jacquesmm]

Thank you for ALL your responses. Regardless of other disagreements, the answer to my question is clear. I will build the boat from Okume. Any savings from using another type of wood are dwarfed by my time and labor input. I believe in doing it right the first time. I will order the Okume Plywood.

I've already built that first boat. It was very heavy and I hope I learned my lessons.

Thank you again for all your help, and I'm sure I'll have more questions!

JLL

If you have already build a boat, there are good chances that you will keep the weight below 65 lbs. Keep in mind lightening holes in all frames.
One weight saving modification that would not be too difficult is foam sandwich frames and seat tops using using blue insulation foam.
I have to do some calcs and maybe test a panel or two, let's hope I find the time before you start.

[anonymous]

I'm in the process of building the Row 13 and it's my first boat. It's taken me longer because I've made some mistakes that I had to fix. Some mistakes are not worth fixing.

I had the idea of making it a light version, but like Jacques said, it's a lot easier (and cheaper) to make a heavier boat first.

I'm glad a choose a simple boat to build as my first one. Although in hindsight, building something like the FL11 or 14 would have been easier and faster. But my 5 year old daughter liked the Row 13 because it's "prettier" and you can't argue with that logic!

If it's your first one, make a simple and heavier one. Or at least get the "practice epoxy kit" to get a feel for things. And read the epoxy book first!!!!!