A-91-3 was 50 foot long with a 15 foot beam. Powered by two 12V71 Detroit Marine Diesels. Armored with twin 50 cal machine guns in forward mount, 20 mm rapid fire cannon in midships mount, two 30 cal machines mounted in the stern deck, two Honeywell crank operated 40 mm grenade launchers as well as personal weapons, M16's, Ithaca shotgun, 45 pistols, M79's. several cases of fragmentation grenades, concussion grenades and 4 pound TNT depth charges. Also carried two cases of C4 with various detonators. Top speed of the Alpha was about 20 knots and had a crew of six. Boat Captain, Radioman/Coxswain, 50 gunner, 20 gunner, engine-man and engine-man striker. T he crew members of all the MRF (Mobile Riverine Force) boats were proudly called, "River Rats".