It is much cheaper for the Shipping Co.'s to pay to insure the crew & cargo. The potential for incidence w/a sec. crew is high & Int'l Shipping Laws are very tricky.
But IMO 2 military options I've heard that have potential but are still some ways out are:
1) Targeted raids fr/ an Amphibious Platform like the MEU, even if its just guys Lasing Airstrikes, they're to comfortable in their little pirate villages.
You could park a MEU off the coast & run fully supported mission after mission up & down that coast.
These guys are not extremist & not dedicated to any cause, for them its just easy money. Make hurt, just alittle, they'll switch to another illegal trade. They're making a living in the bubble caused by the US's full attention focused on the GWOT.
2) Would be something Navy RADM Victor Guillory proposed at the Surface Navy Association luncheon back in March. That the USMC train & assign Rifle Plts in the mission of Non-Compliant/Hostile VBSS.
Now granted he's proposing this as a future mission as the USMC's (SC MAGTF) & USN's Global Fleet Station (GFS) concepts come on line & come together.
He proposes Dispersing Rifle Co's attached to LCS's to assign one Plt per Comp. as the VBSS platoon.
B/c the LCS has the speed & stamina to chase down any pirate skiff there's no real need for the logistical burden of helo's. Only the investment in the E-RHIB for boarding which he proposes the Navy pay for.