I am currently building a bent wood toboggan. I will take you through the steps to successfully make an toboggan out of ash.
Step 1: Cutting the slats
Then, using a thin kerf blade on the table saw, rip the slats to 5/16" thick.
Cut 8-10 slats(I used 7, but cut extra in case of breaking during bending!), depending on how wide you want your toboggan to be.
Step 2: Soaking.
I have found that pre-soaking the slats in water for 2-3 days greatly increases your success rate while bending.
Step 3: Steaming.
The slats now need to be steamed, you can make a steam box out of many different materials. You can also produce your steam in any number of ways. We built ours out of 2x10 spruce and we use an old electric kettle for our steam.
Insert into steam box and steam for 30-40 minutes.
Step 4: Bending
It is now time to bend your slats around a form. The form we use is made from a piece of PVC water pipe. It allows us to bend multiple slats in one session.
Work quickly and be careful, steam can give you a nasty burn.
Let sit in the form for several days.
You could use a moisture meter to track how dry the wood is.
Step 5: Building the Cross Members
Cross members and can now be cut. Mine were 1 1/4 x 5/8 for the deck members and 1 x 2 for the top cross member.
Any hardwood will do, I even saw a company build them out of small branches flattened on one side.
Pieces are milled, rounded over(router) and sanded.
The Top cross member has a 1/2" groove routered into it to receive the slats.
Step 7: Finishing
Open the doors or do this step outside!