The Duckweed Survival House has been designed to remain upright no matter how rough the waves are beneath it. After being removed from its storage bag, it can be quickly inflated via its built-in high-pressure carbon dioxide gas chamber. An air vent on the roof of the shelter allows the intake of fresh air. An underwater stem, containing the gas tank at its base, offers a stabilising function and also a filtration function. Reverse osmosis film near the base of the stem admit and convert sea water to fresh drinking water, which the passengers can access through an inlet in the floor. The square-based survival houses can be tethered together, increasing their stability, visibility and resistance to the effects of wind and waves. Fluorescent markers on the exterior allow rescuers to locate the shelters easily at night.