Corrosion of “Duck” Boat Bilge Pump Discharge Piping
During a recent Coast Guard inspection of an amphibious passenger vessel / DUKW (“duck”) boat, a marine inspector discovered water back-flowing into the vessel’s bilge while testing the vessel’s bilge pump system. An expanded inspection of the system revealed a severely wasted and holed section of the steel bilge piping leading vertically to the overboard bilge discharge port. After inspecting the remaining fleet of six vessels, the same problem was discovered, in various degrees of severity, on four other vessels.
The failure of this piping creates an extremely unsafe condition by rendering the vessel’s bilge pumping system ineffective. Because the wasted section of piping is hidden behind inner sidewalls within the passenger seating section, the problem can persist and evade detection by the vessel owner or operator.
The U.S. Coast Guard strongly encourages owners, operators, and other persons involved with the inspection of these types of vessels to:
Immediately trace out and inspect the entire bilge piping system for wastage or deterioration of metal bilge piping, check the condition of all hoses, hose clamps, supports and make repairs as needed.
Make the inspections of these concealed components part of the vessel’s overall routine inspection process.
Consider installing an access plate on the inner panel at the area of the discharge piping so that the piping is easily accessible for inspection and maintenance. (See image at right)
Inform the appropriate Coast Guard personnel if the system piping has changed significantly or in any way that may require regulatory notification, oversight or guidance for permanent repair solutions.
This safety alert is provided for informational purpose only and does not relieve any domestic or international safety, operational or material requirement. Developed by Sector San Francisco and distributed by the Office of Investigations and Casualty Analysis. For questions or concerns please email Michael.P.Devolld@uscg.mil or email@example.com.