In addition, swells can be developed in the open ocean by surprisingly distance storm systems.. these can roll into the otherwise 'leeward' sides of islands.
This phenomenon can often make normally sheltered harbours on certain Caribbean islands less comfortable or even untenable.
1984 Fast/Nicholson 345 "FastForward"
".. there is much you could do at sea with common sense.. and very little you could do without it.."
Capt G E Ericson (from "The Cruel Sea" by Nicholas Monsarrat)