For what it can help! Wei Wuxian is not a sea-man, but a river man, so his experience with boats has that cast, but that said, piers being blocked means no river trade, so he would be a voice to bring up that if the boat is being sunk, sail it out of the pier to do so, both so it's not blocking port (since in theory one way out they have is by boat, and if boats can't go, then they don't go that way) and also have a means to get back in (so a smaller dinghy or whatnot to get off, he has no idea if people can fly or otherwise walk on water, or heck, swim without getting hypothermia and dying) once its sunk.

Also if anyone has the extra skillset to shove the ship back out of the shallows of port because otherwise, if they all need to sail it, that's another concern.

(There is one sad joke here, and that joke is once they're in the thick of it and have zombie mermaids around, I can ask how his success rate of getting zombie mermaids to help haul the ship out into waters deep enough to sink could go, but prior to that he has zero skill or ability to move the ship himself.)