usually round the wrist that's on the tiller - replacing the silly clip with an "Animal" watch strap (other velcro watch straps are available!
) makes quite a good method of making sure it doesn't come off
I found clipping it to my lifejacket usually resulted in pulling it out as I went for the gearstick. Mind you that is on a good old gearstick halfway down the opposite side to the tiller - the new ones with the gearchange on the front probably won't suffer from that problem.
Could you wrap it round your knee? Itr will depend where the engine enfd is fixed & how you sit etc etc..