Ahm, to paraphrase something on marriage: Shape in haste, repent at leisure.
If you have the depth to do it, those deep straight 'channels between sponsons' John Galera did have long fascinated me. Though that may well be the ultimate in bottom concaves. Losing volume, yeah, well, I think that's a good thing, Rod likes real floaty boards but I always liked something I could push under easily, kick and get well under an incoming wave. With a paipo you're dealing more with planing area anyhow, buoyancy beyond what's necessary for the board to float it's own weight is something I was never convinced was a good thing.
Sanding curves or maybe more importantly forming curves to shape. The boatbuilder's way-
You start with a batten, a straight grained piece of nice thin softwood, not too thick, that you can bend to a curve. Take a piece of plywood and something to do your patterns out of and a bunch of icepicks or awls or finish nails and play with that curve, bend it a bit, set one of your pointy things. look at it, futz with it some, stare at it Work from a centreline, measure a lot, a framing square can be your friend here. Before you cut a pattern, scribe a line along your batten, flip it over, measure, repeat going the other way. What looked good as one side might look really weird when you do the other side too. You learn to see if there are lumps and divots in that curve, picking up that ....skill, ability, trained eye....is a very big part of an apprentice boatbuilder's journey. Some never do. They become carpenters.
That's your outline shape, and then there's deck and bottom cambers, convexities and concaves, but you work from patterns you make, with a batten and by eye.
Then- well, hey, you have some time, take it and work carefully. Cut, or rasp, or surform, or sand, just outside the lines and very carefully You want to be faster than erosion, but not much
john - barely faster than erosion
Thanks John. Erosion here can be pretty severe and fast.
Hi Bob - I think you already have access to these(?) Just in case, or if any readers need to see:
Thanks John, I have a couple of John Galera's boards and not so long ago had the bizarre experience of seeing one of his boards (I think it was the one in the bottom photo), that I'd sold - in a surf museum on the Sunshine Coast. Since these photos John has been experimenting with carbon fibre and I believe is going to make a foil board soon. The board I have in mind has some chines like John's but wings on rail, like this board.
I had half a mal and was bored once...
Where yor tail is V shaped I've cut out an arc. I ended up stripping all the glass, so scooped out the deck so the tail end isn't abrupt. The plan is to ride it finless, so I'm going to add some rail wings. Photo to come.
How does yopur board ride?
I used what I had laying around, so have 3 glass on fins in a line, centre one slightly taller.
Haven't been out on a "good" wave but it does go left and right with no dramas :)
I usually ride a mal.