Marines should not be placed on merchant ships. They should be on U.S. Navy vessels disguised as merchant ships. Why is this so difficult to do?
1. If one just goes by random chance, the odds of a Q-Ship being attacked by the pirates is extremely low...about 0.2% in a year. If 1/4th of the entire Navy is Q-ships, one will be attacked every five years. I think the Navy has better uses for its budget.
2. The pirates have a fairly sophisticated intelligence network, so they're not likely to attack your Q-Ship anyway. NEVER underestimate an opponent. Remember, even if you develop a good cover story for your Q-ship, the best you can do is raise your chance of interception to 0.2%.
That cover story will have to include a believable front company owning the ship, the ship being under contract to deliver a legitimate cargo, the crew telling the right stories in the waterfront bars before they sail, and the ship going from port to port loading and unloading legitimate cargo, instead of sailing back and forth in the target zone.
3. Q-Ships have an undeservedly good reputation. During WWI, twice as many Q-ships were sunk by submarines than vice-versa. They did even worse during WWII (three out of the 14 operating in the Atlantic were torpedoed, no subs were sunk...)
Ironically, the British WWI Q-ships depended upon the U-Boat commanders being humanitarians who would not sink a "civilian" ship without giving the crew and passengers the opportunity to safely disembark, first. Once knowledge of the Q-ships got out, sub commanders said " **** that" and started sinking all ships without warning. The only way Q-ships worked after that was to look so decrepit as to "not being worth a torpedo," and thus luring the sub to the surface to use its deck gun.
The only long-term solution is to ensure the piracy does not pay. I've already posted about having Navy ships re-capture any taken vessels regardless of threats to hostages.
The other way, of course, is point defense on the merchantmen themselves. I agree that, in the near term, defense teams of US Marines could be stationed on US-FLAGGED vessels passing Somalia.
Certainly, arms could be placed on normal merchantmen for the crews to use. But someone would have to incentivize the crew to actually *use* them. The Somalian pirates haven't routinely abused their hostages, so why should a $15,000/year deck hand on a Liberian-flagged tramp steamer risk his life and start shooting?
Ron Wanttaja