Captindoug......
If I was going to stretch it from the 13 -9 and 1/4 it to 14.... Not sure what a few more inches would do since there is a good amount of rocker in it the way it was designed and what 3 more inches would do. I can not see any problems in making it the full 14 ........
I checked with Uncle John....... Here is what he had to say.
Wouldn't be a problem for them to be cut a couple of inches longer to make up the difference. Truth is it could probably be stretched to 16' and come out all right by spacing the rib sets a bit wider. If I was going 16' I would add a rib.
The rocker has it benefits , you run up on a log and get stuck back of the mid line , then just go forward and float off of it and keep going. Now without all the rocker in it you might be able to go over that log with just a bump since it would be a shallower draft boat. You would lose a lot of the ability of spinning the boat around on itself or making quick adjustments in the direction ( maneuverability ) of travel since there would be more resistance to the boat from the longer water line.
When I get a chance to try it out then I can make better suggestions but only as far as my likes or dislikes. One thing I do know from the pirogues....... The skiff will be able to be paddled and nosed up on the river bank, might call it grounded ( 90 degrees to the bank ) so a person can just stand up and walk out of it without a problem. Get back in it to raise the nose up and float off , no more WET FEET.
Naz..........
I did my normal trick........ Both the green under the rail and the yellow along the water line is the Duck 667 Pro Series Electrical ( Vinyl ) Tape.
I have used it on other boats and it is still on them and stuck tight. If you would be worried about the water weaking them , a coat of varnish over them waterproofs them.
I use to paint them on the boats , then I found this tape , tried it and really like it.
Chuck.......