Comparing a sea kayake to a flat bottom boat is apples and oranges.

I have friends on the island and I can tell you that I know why his boat is some what larger and a deeper draft than that. The current between the islands can be very strong. And the winds can make it difficult to hold a true course with a flat bottom boat. Even just going out between the islands can be a problem if the wind comes up. You still have to be able to make a safe cove or you will still be in trouble.

I would not do it. But if you choose to good luck.