For a lobster type boat of 35" long do I have to stay with the "can" type motor or can I put a brushless in it as in the planes, and which one is recomended. Please help with info

It is your model you can do whatever you want. The question is do you want the model to travel at scale speeds on the water or do you just want a boat to run like a rocket? The choice is yours.

Tug

Kaoma,
One of those choices, you know? And like 'Tug' said, just depends on what you're looking for. For most scale applications a brushless motor is a huge over-kill kind'a thingy. But it's your wallet.
- 'Doc