different types of protective clothing for maritime personnel were compared in 3, simulated, survival environments: immersion in cold, rough seas; exposure to cold wind, spray and waves atop an overturned boat; and exposure to cold air and waves in an open, one-man liferaft. the test garments were: flight suit (fs); two-piece wet suit (ws); insulated, loose-fitting aviation (ac) and boatcrew (bc) coveralls; uninsulated dry suit (ni); ni with a 5 cm tear in the shoulder seam (nx). all garments were worn over cotton thermal underwear; an additional layer of insulated, short-sleeve underwear was worn with ni and nx. 8 coast guard crewmen were the test subjects; mean age = 23 yrs; mean ht. = 175 cm; mean wt. = 72 kg; mean body fat = 11 . significant differences between cooling rates in water and those on the boat or in the raft were found for all garments except ni and ws (boat). the results demonstrate that survivors maintain higher skin temps. and slower cooling rates out of the water, even when exposed to continuous wind, spray and waves than when they remain immersed in rough seas. insulated, intact-dry-suits provide better immersion protection than do either tight-fitting wet suits or loose-fitting coveralls; leaky 'dry' suits provide no better protection than do loose-fitting coveralls. the best survival environment is provided by the one-man liferaft. linear cooling rates were used to estimate survival times in 6.1 c rough seas for personnel wearing each of the test garment-ensembles