In offshore fly fishing, as with any other kind of saltwater fly fishing, you want to experiment with retrieves. It’s probably best to start with a rapid retrieve because the big fish are chasing baitfish, they're chasing squid, and those things are really booking. They are trying to get out of there, and they have nowhere to hide except using their speed. Start with a fast retrieve; try a slow one if that doesn't work. Try an erratic one, but you have to experiment with all different kinds of retrieves before you crack the code.
Try both a conventional strip and a hand-over-hand retrieve into a stripping basket. Each gives different actions to the fly. From a boat, it's even more important to keep that rod tip low or in the water, because you are further above from the water than if you were wading. The strip strike is essential being so far above the water; the hooking angle is really compromised if you raise the rod tip to strike.