A new Antarctic research vessel to be chartered by the National Science Foundation was designed and is under construction by North American Shipbuilding, Inc., Larose, Louisiana. A full model test program was required by NSF to verify that the proposed, design would meet the vessel operational requirements. In particular, the ship is to break 3 ft (0.9 m) of ice at 3 kn (1.5 m/s) continuously and break through pressure ridges with a 6-ft (1.8-m) sail and a 20-ft (6. 1 -m) keel. Ice model tests were made in CRREL's ice towing tank. The test program included resistance and propulsion tests in level ice, tests in ridges and ramming tests in ice floes of up to 6 ft (1.83 m) in thickness. The test results described in the report indicate that the proposed ship design with 8.8 MW of power available at the propeller would meet or exceed all operational requirements in ice: the power needed to operate continuously in 3-ft first year level ice at 3 kn was estimated at 6.5 MW: the vessel was found to be able to ram through a 38-ft (11 -m) keel ridge; finally, when rammina in 6-ft thick level ice at an impact speed of 6 kn (3.1 m/s) at full power, the vessel was predicted to penetrate by about one-third of a ship length into the ice. Antarctica, Ice ridge, Model tests, Icebreaker, Level ice, Ships.