days before GPS.
Whe we went in there in daylight in the late 70's it was unbuoyed, and we found it a challenge in daylight.
To a couple like Ian and Fiona, who have demonstrated great seamanship, it was probably not a major problem.
They had GPS, confirmed by buoys.

I am much more impressed by their average speed, given the size of the boat and the fact that they had no engine for most of the voyage.

Having overcome the challenge of getting there, they will enjoy the Caribbean more than most, and a LOT more than those who get there by air or cruise ship