He wakes up to the sounds of water and the feeling of the wooden planks underneath him gently swaying.
He is on a boat! On the ocean!
It's a weird boat. It's perfectly circular, like some sort of lifeboat more than a vessel meant to go anywhere under its own power, but its construction is very proper, at least from the perspective of the age of wooden ships — everything is wooden structures and brass fittings, sturdily built and freshly polished. He woke up on a large circular deck, completely empty, and separated from that deck by a railing is a slightly lowered ring that, unlike the central area, is occupied by nautical paraphernalia such as ropes, an anchor, and various wooden and iron gadgets.
The view of the ocean all around is excellent. The wind is calm, and there's an island visible off in the distance, to the left of the sun.
There is an anchor, and a suitable length of chain. There are various ropes, arranged to be ready for use or tied into bundles. There are capstans and cleats. There are stairs back up to the central deck — from this side the railings can be seen to have latched sections that swing outward at the top of the stairs.
There is no bridge, or any sort of control panel. There are no hatches. There are no sails, not that they would be any use while becalmed.
The boat turns in circles again, possibly a little more enthusiastically. The sun and the distant island remain distant.
The breeze seems to come and go, but it turns out that it's noticeable when he stops because it stops slower — and if he's pacing in circles it isn't felt because it's keeping pace with him. The net result of this is still him and the breeze and the boat going in circles, though.
This technique results in the boat sloshing forward, much in the manner of a cup carried by a walking person but inside-out. It seems that not just the air but the water moves.
Observing that it's effective seems to make it more effective. In fact, it's not really necessary to walk quickly forward, or to walk at all — there's something in the thought or the manner or the pose of going forward that works. And the ride's much smoother that way.
It doesn't take long at all to get close.
The part of the island he's approaching consists of an intimidatingly rocky shore with a stone fortification built above it. Directly ahead — in fact, on the exact same line as his travel so far — is a stone arched tunnel through the rocks and extending under the walls, large enough for the boat to enter.
The boat unproblematically enters the tunnel; the ceiling is very low but not so much that he has to duck.
In the darkness of the tunnel, the other end can be seen to be a sort of underground dock, circular to fit the boat, lit by some flickering yellowish light. The tunnel isn't actually very long.