the 39th Cavalry Platoon, 9th Division, and were based out of Ben Luc and Đồng Tâm Base Camp, although they often deployed from fire support bases. The Green Berets stationed in Moc Hoa became proponents of the PACVs, using them in many of their early operations. Search and destroy raids conducted out of Moc Hoa in November 1966 caught the Viet Cong by surprise and resulted in many Viet Cong deaths. The PACV's speed, maneuverability, and firepower lent themselves to many types of missions, including patrolling, search and destroy, escorting other ships, raiding, reconnaissance, medical evacuation, transporting artillery pieces, and providing fire support to infantry. It was best suited for ambushes and raids, especially at night, when it could be easily concealed behind reeds and swamp grass. Although it was too loud to be very effective at surprise attacks, it could use its speed to raid Viet Cong bases and escape before they could react. The PACV was found to be most effective when employed in combined arms operations alongside helicopters, artillery, and other watercraft; patrol missions conducted in concert with air cavalry or Hurricane Aircat airboats were found to be especially effective. The PACV's low profile and radar also meant that it was used as a stealthy stationary radar station when its engines were off. However, Army evaluations found that the ACV had insufficient firepower, being unable to damage armored or fortified targets, and recommended that it be outfitted with heavier weapons such as TOW missiles, 20mm autocannons (such as the M139 or M61 Vulcan), or 106mm M40 recoilless rifle. They also found that it could be too loud to be used effectively for patrol and interdiction missions. Fuel resupply was another frequently cited issue for longer missions, especially given that no adequate method of refueling in the field existed. The PACV was frequently compared to a helicopter because of its speed, terrain crossing ability, maintenance requirements, and cost. Army ACV units operated similarly to air cavalry. Operating these highly specialized vehicles required pilots and maintenance personnel undergo considerable training, with pilots requiring 75–100 hours of flight experience before participating in combat. Training requirements meant that the Army had to set one craft aside for training for 14 days every month. Troops riding in and on the PACVs also needed training to use them safely: during evaluation, one soldier died when he fell into the hovercraft's intake, and another