Newbie question on leaving in forms

Submitted bygatorkiter onWed, 12/09/2020 - 14:28

I'm sure you guys have heard this question before, but I can't find the answer searching the forums:

Do people build wood strip kayaks using internal forms left in the kayak, with no strongback, just forms with large center openings? If so, is it more difficult than using an internal strongback?




that's not how you would approach a strip built boat.

there are two main reasons:

1) you need to align the forms with respect to one-another to get the correct kayak shape, so you need either a strongback or a long flat table to which you would temporaily attach your forms in proper alingment to one another in all three dimensions, height, length, and depth.   the forms don't hold themselves in space by magic (it would be a heck of a magic trick though:)

2) you need to glass/waterproof the inside of the i am not sure how you would glass the interior without splitting the boat in two anyway....typically along the shearline...and then once you glass the interior you now need to reassemble the two your 'internal' forms would need to be broken to break the boat in two.   it would be pretty challenging smoothing and glassing the interior of a strip built kayaks with forms every 12 inches to have to work around.

because of these two points, you would be adding a lot of labor, complexity and time if for some reason you still wanted to have internal forms (even if they were like ribs/open in the middle) because once you have created the hull and deck, you now actually don't need the forms and they are now just adduing complexity to the construction process with no value.




Mon, 12/14/2020 - 12:28

On this board, there have been people who had their hulls expand or close up when left with no forms inside. Its not common for builders (like me) to glass the outside of a hull, get side-tracked and do the inside a month later and find that the hull no longer mates with the deck. So, I advise people to put some forms in the hull whenever you glass it (outside or inside) obviously after the epoxy harden a bit. Then some straps around it holding it in shape. Decks since they are more flat, never seem to distort much. So, if you use forms with an internal strongback, you might have to cut some forms out?  Or  fit the hull on the forms once the inside is done? I use an external strongback that I remove forms for that chore. You don't need all of them - just around the cockpit area fore and aft a bit.

    I had one hull close up a bit where I had to put braces inside holding it open to attach the deck. That's when I learned to be cautious about that happening.