Here's an excerpt from an account of an encounter :
The speedboat was now parallel with us, its seven Somali occupants sussing us out as a potential target. They were armed with rocket-propelled grenade launchers, clearly visible to the trained eye of one of my fellow lecturers, Brigadier Hugh Willing. We were about 200 miles off the Somali coast, so the pirates must have been operating from a "mother" ship, perhaps a captured Taiwanese fishing vessel, a few miles over the horizon. Captain Brocklehurst fired two warning shots with a flare gun to show the Somalis that he knew they were there. Slowly the speedboat fell astern of us and veered off westwards. The impressive defences on Discovery – rolls of razor wire all over the stern rail, bundles of logs to be released to fall on any craft attaching itself to our hull – must have deterred them.