Salem

Hello i just swimmed into someones claim in a boat, and when i exited boat at shore it appears that im whole into claim - cant move, get into my boat or do anything else without trespassing...

This is normal. You'd normally be stopped from even entering the claim if you walked up to it, but since you entered the claim at a "random" point in the middle (instead of at the edge), you're stopped from moving at all. If you don't have a crime debuff, you could drop inventory and port home. Otherwise, just turn on criminal acts, take the crime debuff and BB drain, and walk out. Not sure if you can get your boat back, though.