<p>A floating dock including a submersible platform including at least one buoyancy tank wherein the buoyancy tank has a plurality of compartments each of which has a permanently open vent through which water is freely flowable into and out of the compartment and an inlet which enables air to be expelled from the compartment into the atmosphere or enables compressed air to be supplied to the compartment via a non return valve which causes water within the tank to be forced out via the vent, thereby increasing the buoyancy of the tank. The vent does not have any valves associated with it and is permanently open to the sea. As a result the floating dry dock of the present invention may be lowered and raised faster than conventional dry docks which rely on valved vents to control entry and exit of water into and out of their buoyancy tanks.</p>
