Sometimes skellies spawn, other times they arent there.
Do they have specific times the cannons are manned or is it purely random?
@daringclarky
The skeletons on the cannons respawn some time after the cannon has been left unused, as they eventually get off of it and wander aimlessly until despawning, later being replaced. Going a distance away despawns the skeletons and respawns them on approach. The whole crew dying also resets the island's skeletons.
@daringclarky
If you are talking about during the times you are sailing near an island then its not random. When you sail close enough and you are in the line of fire the skeleton will shoot at you. The skeletons are triggered when you enter a certain radius of the island. Sometimes it takes longer than others but the skeleton will always shoot you if you enter its firing zone.