International law says private ships can not leave the port armed. Why not equip a few of the high speed boats like the Coasties have in the port os Seattle and just teather them along side until a threat is detected. If they are not needed (or even if they are) then hook them up with the next target ship going back the other way. I doubt it would take very many thwarted attemps before the incidence of attacks would drop way off or stop almost completely. I'm surprised that Blackwater or one of those security companys kicked out of Iraq hasn't started offering this service already. Plenty of mercinaries out there to man up the boats.