Originally posted by Trike:

Have yet to discover what kills you in the ocean on a raft, but okay.

As you may have seen there is something(s) out their that make the Raft a poor choice for ocean sailing.
But they still retain some charm in short range fishing expeditions I think. Valheim general rule I think is always make you base camps in Meadows or perhaps Black forest Biomes and sally forth to the newer areas you meet.

Personally when I find anew island when I can I sail all around it. to see how large it is. Fine a potential safe port build a base with a Teleportal to my central hub their then If I discover other interesting locations link teleportals from the landing site to that area. If you are killed this greatly speeds up the corpse runs.

Good luck & Happy exploring!