Her outer hull plating was constructed with -thick high tensile steel. "Edisto" had a double bottom above the waterline with the two "skins" being approximately apart, insulated with cork. Framing was closely spaced and the entire hull girder was designed for great strength. "Edisto"s bow had the characteristic sloping forefoot that enabled her to ride up on heavy ice and break it with the weight of the vessel. "Edisto"s stern was similarly shaped to facilitate breaking ice while backing down. The sides of the icebreaker were rounded, with marked tumble home, that enabled the ship to break free from ice by heeling from side to side. Such heeling was accomplished by shifting water rapidly from wing tanks on one side of the ship to the other. A total of 220 tons of water could be shifted from one side to the other in as little as 90 seconds, which induced a list of 10 degrees. Ballast could also be shifted rapidly between fore and aft tanks to change the trim of the ship. Diesel electric machinery was chosen for its controlability and resistance to damage.