Like other YAG 300 vessels, Cougar was 75′ long overall, 18′6″ wide, had a draft of 4′6″, measured 70 tonnes, and was powered by twin 6-71 Detroit Diesel engines. Cougar was arranged in typical naval fashion with officer’s housed forward with the galley and their own head, an engine room midships, and cadet room aft with 12-14 bunks in double tiers. The heads are equipped with a pump-action lever, that can be used to pump sewage into the black water treatment tanks held aboard or into the ocean water. Above decks was the wheelhouse mounted on the forward cabin's coaming; aft of that, the exposed breezeway; and, mounted on the after cabin's coaming, a Zodiac launch as well as a food locker and barbeque. Above the wheelhouse was an open bridge, fitted with a chart table and a gyrocompass repeater. A second gyro repeater was fitted on the quarterdeck. Cougar was equipped with a small navigation radar, with the display located in the wheelhouse.
In 1954 she was built for the RCN as YFM 308 (Yard Ferry, Man) and served as a harbour ferry boat. Re-designated as YFP 308 (Yard Ferry, Personnel) in 1960, she was transferred to reserve status due to defence budget cuts.[4] When she was brought back into service in the mid-60s, she was redesignated YAG 308 Cougar and served as a training vessel for regular and reserve forces until she was removed from service in 2007. She was sold in 2011 to private interests.