So you're saying that they are completely useless? They say that the "set fire to enemy attacking ships" he is attacking isn't he? I had birs with them but the fireships didn't kick in till the birs died..
Thats why I find FS useless. Fireships also always attack last so thats why they didn't do anything. They kill tri, LS, and Bir that is all. They do not defend sieges or kill hydras.