The problem - if such you wish to call it - lies with a "reality disconnect" on the part of players, not their characters.

Assuming the CT Spinward Marches setting, the *characters* know quite well that their ship is basically a motorized rowboat visiting African coastal towns in search of semi-legal profits, while mounting one or two WWI Lewis guns for self-defense.

But the players *simultaneously* believe that

1) they're swanning about in the equivalent of a US Navy WWII motorized Patrol Torpedo boat and

2) that all those movies wherein brave PTs dash in at high speed, sink the destoyer and then dash away again with only a few dramatic bullet holes (and maybe an NPC or two getting hit) are accurate protrayals of PT boat tactics 

Never mind that the actual wartime missions mostly involved motoring quietly to a spot where previous experience showed Japanese supply boats were liable to be encountered, waiting with lights off and motors idling for these heavily-laden slow-moving targets to put in an appearance, drifting quietly into torpedo range THEN launching and immediately hitting the gas, leaving at flank speed under heavy smoke while earnestly praying that no searchlights found them . . .  

So when the players decide to turn pirate, they think they have some sort of reasonable chance at success.

Of course, they're actually in the situation of a modern Somali pirate gang in a motorized rowboat who suddenly find themselves facing a target which ALSO mounts several automatic weapons . . .