Rascal question - plank bending

[DavidS]

I've gotten to the point of finishing all of the plywood on the first layer of the hull and also the second layer of plywood on the bottom.

http://www.mindspring.com/%7Edavidshively/rascal-hull.JPG

Time to start planking....

So I went out and found some really nice looking african mahogany and resaw/planed it down to 1/4 inch. Cut out a plank for the front topside and it seemed to work OK.

Then I ran into a problem: at the aft end of the boat near the transom the planks have to bend cross-wise to conform to the radius of the transom as it goes from the chine up to the shear (i.e. the plank needs to "cup" across its grain). Well, that african mahogany just doesn't want to do that and I broke a couple of test pieces trying.

I tried steaming/boiling a piece and that helped some but it still was on the verge of cracking and it was also sort of warped. From what I've read african mahogany doesn't steam well but this was my first attempt at that. As you may know, the plans call for genuine (honduran) mahogany and that isn't easy to find here and it is about $10bd/ft.

Am I doing something wrong?

Other options:
1. Go pay the $$ for genuine mahogany - will that bend easier?
2. Try spanish cedar
3. Plane it down to 1/8" and use two layers
4. "back out" a piece so it conforms to the hull (i.e. make it concave by cutting out part of it)
5. Start a big bonfire and sit on the couch and watch TV

Thanks,
Dave

[PaulC]

Nope, it's way too late for the TV option. She is looking really sharp!

[pcford]

Work with nature.

1. On a bright, sunny day:
2. Water a patch of your lawn.
3. In direct sun, place the outside of plank down on the wet grass.
4. Have your favorite beverage and watch Oprah.
5. When the plank has cupped a bit more than you want, hang the plank.
6. Won't take long, maybe a couple hours.

[DavidS]

Wow. Plank bending while doing nothing.

That's my kind of work!!:D

Dave