Or maybe a return of the q-boats.
One heavy bore sea modified gun. Specifically this...
http://en.wikipedia.org/wiki/Royal_Ordnance_L9, that would level the mothership and the little dinghys they board with. Even handguns would help.. Sheesh to leave these men undefended is not right.
Edit, I chose the above ordinance based on the round fired, being cheap and inert. With a range within visual sight. Close enough to confirm threat. Like AK waving guys in shabby clothes and barefeet.