Why is a watertight dry-dock gate important for reducing pumping costs?

A watertight dry-dock gate is essential because it prevents water from leaking into the basin once the dock has been pumped dry. Achieving the maximum possible degree of watertightness between the gate and its seating is critical to avoid continuing and expensive operational commitments for pumping out leakage water.1

While the pressure of the water outside the gate helps provide a powerful sealing force, the effectiveness of this seal depends on the precise treatment of the contact faces between the gate and the dock structure. Historically, this was achieved using timber linings on the gate bearing against accurately dressed granite stops. Modern alternatives, such as stainless steel facing bars and rubber linings, are also used to maintain this seal and minimize the ongoing costs associated with removing water that would otherwise seep into the dock.1