"Acacia" was initially armed with a 3"/50 caliber gun mounted behind the pilot house. She also had two 20mm guns, one mounted on top of the wheelhouse and one on the aft deck. She carried these weapons in the Great Lakes under a wartime agreement with the Government of Canada. The Rush-Bagot Treaty had largely demilitarized the lakes, but the United States and Canada agreed to suspend some of its provisions during World War II. After the war ended, the treaty came back into full effect and all of "Acacia's" on-deck armament was removed, leaving only small arms for law enforcement actions. In 2006 "Acacia" and the other 10 Coast Guard cutters in the Great Lakes were armed with M 240B machine guns. This action was taken due to greater concerns regarding smuggling and terrorists entering the United States by boat. It was preceded by consultation with the Government of Canada under the terms of the Rush-Bagot Treaty.