How do you use a manual marine toilet?
We've just bought our first cruising yacht, a 2008 Beneteau Oceanis 37. It has a manual Jabsco toilet, and I want to make sure the family knows exactly how to use it without blocking it or flooding the boat. What is the correct sequence for flushing and leaving it safe?
Answer
To use a manual marine toilet, you must pump water in to clear the waste, then switch the valve to pump the bowl completely dry. The golden rule is that nothing goes into a marine toilet unless you have eaten or drunk it first, with the strict exception of minimal single-ply toilet paper.
The flush cycle
Most manual marine heads, like the Jabsco Twist 'n' Lock or the RM69, have a pump handle and a small selector lever. This lever switches the pump between 'Flush' (wet bowl) and 'Dry Bowl' (pump out only). Here is the standard sequence:
- Move the lever to the 'Flush' position and pump the handle three times to wet the bowl.
- Use the toilet.
- Keep the lever on 'Flush' and pump the handle steadily. This draws in raw water from outside and pushes the waste out. You usually need 15 full strokes to clear the bowl and push the waste through the discharge hose.
- Move the lever to the 'Dry Bowl' position.
- Pump another 15 strokes to empty the bowl completely and clear the remaining water from the lines.
Leaving water in the bowl when sailing results in it sloshing out. Waste left in the pipes will calcify and smell. If you have a Jabsco Twist 'n' Lock model, push the handle down and twist it 90 degrees to lock it. This prevents backflow.
Seacocks and holding tanks
The seacocks must be open before the toilet will work. You will find two bronze or DZR brass valves in the hull near the toilet. The smaller one is the 19mm raw water inlet, and the larger one is the 38mm discharge. Open both by turning the handles in line with the hoses.
If your boat has a holding tank, check the diverter valve (Y-valve). Pointing the lever towards the tank directs the waste there. This is a legal requirement in many marinas and coastal waters. Pointing it overboard discharges directly into the sea. Always ensure the holding tank breather vent on the outside of the hull is clear. A blocked vent causes a holding tank to pressurise and burst.