I have been taking out a double Gatling gun Pyramidion recently. It is not very effective by itself, but with a Hwacha goldfish backing it up, it is a very formidable ship. Actually the goldfish is the one who gets the kills and is focus fired most of the time, but It wouldn't get those kills nearly as fast without my Pyramidion stripping the hull armor.
There are certain ships I take when I can trust my teammates to back me up, and certain ships I take when I can't. The blender fish, sniper variant pyramidion, and Galleon are ships I take when I don't think the other captain can be trusted to work with me. The double gat Pyramidion, sniper variant junker, spire, and squid are ships I take when I can count on my teammates to cover for my weaknesses.