I had mastered sailing when I entered the boss battle. Ater successful completion, I was given this new skill. I had no points to spend. It appears just as Hile has said, a free skill. Woot! Useful for times when you're battling multiple targets and a Revenant spawns next to you. It quickly recharches your broadsides, full sail, coming about and other skills so they may be used again. It also recharges the deck cannons faster but that isn't as useful because they might not all need them when you hit it. It's not instant but it is a lot faster. It be fun to use this in the boss battle.
