I used a Paslode framing nailer to attach mine...
Seriously, A little sanding and careful work especially around the edges with marine goop should do the trick. The expansion and contraction of the PVE in cold water and hot sun means that a flexible adhesive like marine goop would probably work best.
You could also have them printed onto Vinyl and then attach that to your sleigh, expensive but doable.
Or you could just take the motor off... inexpensive, healthy, and safe!
Cheers...