You can get your boat onto the land and sail around.
It's not super consistent, but it has to be a diagonal piece of land, once you get onto land, you can get back into the ocean via the same diagonal piece of land.
Please see attached screenshot:
1. Armored Boat + Iron Wind 2. Walking Cane 3. Sleek Hat 4. Marble Suit 5. Coffee 6. Wave Boost 7. Sail directly at the land and you have a Land Boat!