Time to talk about that fun fun fight known as the Gunship!
On normal 10- and 25-man mode, this fight is extremely easy for most raid groups. There is some execution required though, and lazy play can still result in a wipe.
Make sure you have your rocket equipped, especially if you switch specs. I've seen too many players not be able to cross to the other ship because they forgot. Now might be a good time to remind you to always ensure you have a presence selected - when you switch specs it disables any presences.
Pull/Phase One: This is done several ways. I won't try to cover them all, but just keep in mind the way I describe it might not be the way your guild does it.
Our melee stay on our ship for the first part, killing the boarders. The first boarder is usually a small elite; I PS>IT to get diseases going, then wait for the Sergeant to spawn. Once he does, I pestilence and Death & Decay. Then just dps on the Sgt. Be wary of his whirlwind - it can hit pretty hard, so I tend to run out when he does it. Since it's an aoe fight, remember your aoe rotation is pretty simple: keep spreading diseases, then make sure to use D&D on cooldown. If unholy, keep desolation up with one blood rune, and you should be able to blood boil at least once. Frost and Blood can probably blood boil twice. The boarders should be dead about the time the Mage comes out, if not before if you're melee heavy. Don't forget to watch the deck for where rockets are going to land. I try to stay out of them to make it easier on the healers. You can take the occasional rocket, but for the most part it's not a dps race.
Phase Two: I get asked to kill the mage, so I jump across and hit her a couple times, then pop my gargoyle (for unholy, my ghoul is up on boarders) and/or other cds. On my second trip I jump and summon my army. DPS burst is important here - getting the mage down FAST is your most important goal. After that, as I run back to my ship, I hit the axe throwers and pestilence to help kill them - or target them with my army. It's not essential, but assisting in getting them down before they become elite is helpful.
DPS per se doesn't really matter on this fight. Just controlling the adds is most important. High dps helps, but execution and timing is what counts. Most WMO/WOL parses don't even include Gunship in their numbers, so don't trouble your e-peen over it. Just get the job done.