A 7'9", 33 lb, 1-1/2-sheet Fly-Fishing Pram

[Charlie43]

I've built a half dozen of these flat-bottomed, single-chined prams in various lengths, and it's a hull form I keep returning to. This time, I'm trying to see how minimalist I can be and still have a safe, fly-casting platform.

A boat weight of 33 pounds is a guess, but probably close enough, because the planking will be 4 mm okoume; the framing, cedar, and the scantlings as light as possible. Design displacement is 180 pounds (= boat weight + a 9 stone rower + oars & gear), which puts the nose on the water, keeps the stern just clear, and offers a theoretical hull speed of just over 4 MPH. The beam is just right for 6.5' oars when grips are overlapped by 2" and the gearing is 30%. Haven't yet decided whether I'll build it S&G or POF. Costs for a finished hull should be under $150.

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The table of offsets is self-explanatory. From it, HULLS will produce the expansions -- aka, cutting patterns-- most builders are familiar with. The expansions could be created by lofting the boat by hand. But I'm lazy and only loft enough to pick up bevel angles.

The wire frame is just that, a wire frame, a minimalist 3D lofting that shows none of the detailing such as crowned transoms, scuppered gunnel, radial frames, doubled skegs, or a foot stretcher,  whose dimensions and placements come from from separately created construction drawings or on-the-shop-floor improvising.

The 2D drawing plots the boat's essential lines, faired to the nearest 0.01" of an inch.

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[Charlie43]

After messing around on the drafting table for week with some 1-1/3 sheet designs, I've decided to do what is easy and familiar, another Camp Britton pram, but this time as light-weight as possible short of resorting to SOF.

To that end, I stripped my 'winter shop' --what most people would call 'a front room'-- of half its furniture and set up my building frame. Friday, I borrow the help of a neighbor and pick up my ply from Crosscuts. Meanwhile, I go through my tool chests and clamp cabinets and begin making construction drawings from my table of offsets.

It's good to be building again.

[Charlie43]

Two sheets of 4 mm, BS1088 okoume were bought Friday, brought home, and laid across my building frame to become a temporary lofting table. Metric ply tapes out at 48-1/16" x 96-7/16" imperial. So I redrew my plans to capture the extra length and will be building a true 8' foot boat, not the 7'6" to 7'10" that is normally cut from 4' x 8' ply. I'm still targeting a boat weight of 33 pounds (15 kilos), and the boat will be cut from 1-1/2 sheets. Therefore, ply costs are a tolerable $84.