The main dependences for determining the coefficient of buoyancy reserve and the draft of flat flat units with an increased and stabilized buoyancy reserve are given. These dependences show that for flat flattened units completely wrapped in a flexible waterproof material, when they are on the water, the draft and buoyancy reserve coefficient do not change over time. In turn, for flat raft units partially wrapped in a flexible waterproof material, when they are in the water over time, the buoyancy factor decreases, and their draft increases.