What Is a Deckwash Pump?
A pressurised water line for washing down the deck — the cure for anchor mud and fish day mess, and a friend to your fresh-water tank.
Deckwash is a pump that supplies pressurised water to a deck outlet, usually forward and sometimes aft, where a hose is connected. There are two arrangements: seawater (unlimited supply, ideal for anchor and chain washing) and fresh water (linked to the tank, for the final rinse). Good installations combine both with a choice of valve.
Its biggest customer is the anchoring gear: chain coming up from muddy bays is cleaned with pressurised water rather than buckets and brushes; sending muddy chain down into the locker speeds up both smells and corrosion.
Problems and rules
Dry running: if the pump is started with the seawater line valve shut, it will damage its own impeller; the valve and switch should be linked in one routine.
Winter freezing: if the water in the deck line is not drained for lay-up, the pump and hoses can split.
Pressure drop: a blocked suction strainer or a kinked hose are the two usual reasons behind the complaint that 'the pump has gone weak'.
The other benefit is economy: washing the deck with seawater and using fresh water only for the final rinse greatly extends tank life. Making it a habit to rinse the chain before it goes down to the windlass turns the chain locker into a completely different place.