Gilbert Park explains how he replaced the hoses on the PBO Project boat Maximus and shares his top tips for sea toilet restoration...

With seacocks previously installed in the Maxi 84, it was time to connect the hoses. The first thing to decide was what sort of installation. As Ali explained in her article about fitting a sea toilet, there’s more than one way to do this. All options require the sea water inlet.

The simplest option has the waste going straight out to sea, but this setup can’t be used in harbour for obvious reasons, and preferably should only be used at least three miles out to sea.

The ideal option is to fit a holding tank, but this is considerably more expensive and wasn’t available to us at the time. More expensive still would have been to fit an electric loo with a holding tank above the waterline for easy emptying in dock or at sea.

A consideration for all systems is that on Maximus part of the toilet is on or just below the waterline with the boat in harbour.

At sea. with the boat heeled over and perhaps digging the bow in it will be well below the waterline. The risk then is that the tubes, already full of water (from use) may siphon water into the toilet and from there into the boat.

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To prevent this vented loops must be installed into the input and output lines. These U-shaped tubes have a one-way valve on the top that lets air in (breaking the siphon potential), but seals off with any positive pressure allowing fluids to pass freely in the right direction.

Unfortunately, supply chain difficulties meant tails for the seacocks were in short supply and time was limited to connect everything up so I had to find ways around not being able to change the tails. For the two basins I had to fit reducing spigots so I could connect them up.

Tools and hose

There are some important points when installing pipework of this type. Use good quality smooth bore, spiral reinforced flexible hose. Don’t skimp on this, both for safety reasons and also because cheaper tubing may become permeable allowing smells to come out.


Anti siphon vented loop

If you have old tubing and wonder if it needs replacing, take a damp (not wet) piece of cloth and rub it along the pipework. If it smells, replace the tubing. If not, consider replacing it anyway if it’s old as it might fail. Replacing the heads tubing during your cruise spoils the day!

Three inexpensive tools, although not essential, will make the job easier. A plastic pipe cutter makes sure the cut is square and clean, while a hot air gun helps with removing the old pipes and softening the new.


A plastic pipe cutter makes clean, straight cuts a breeze

Getting at the hose clamp screws can be difficult. A flexible socket driver makes it much easier. The tubing may be a tight fit on the spigots. Water on the joints may be sufficient to allow it to slide on.

Oil and other lubricants are not recommended as they can damage the tubing. I’ve found the hot air gun the best solution to warm the tubing making it an easy fit. I don’t recommend a naked flame as you may inadvertently weaken or even burn through part of the tubing.


Very gentle heat from a hot air gun makes pipework more malleable and easier to fit, but it’s easy to damage the hose. Softening in hot water is a safer bet if available

Putting the tube into hot water supplies both heat and lubrication and may be useful away from the dock.

Double clamps

All connections should have double hose clamps, preferably with the screw parts 180° apart. This allows an overlap at these points so pressure can be applied evenly.

All clamps should be made from 316 stainless steel in their entirety. Some clamps sold online have the strap made of stainless steel but the worm gear made of mild steel which, of course, will corrode with time.

Once installed, fit small bits of rubber, plastic or tape over the tail ends of the clamps to prevent injuries as they can be sharp. One very important point is safety – wear gloves when near the fittings for the toilet as well as eye protection.

I put all my tools in a bucket as I used them to keep them separate from all the others and to remind me to disinfect them. Bugs can live for a long time in old tubing.

Thanks to our Project Boat Supporters

Dell Quay Marine, Osculati, Raymarine, Shakespeare Marine, TruDesign, Screwfix, Coleman Marine Insurance, MDL Marinas, Premier Marinas, seajet, Marine & Industrial, Clean to Gleam, Dometic, West System, Farécla, Navigators Marine, Lewmar, RYA, Aqua Marine, Ecobat, Victron Energy, Scanstrut, T Sails and XP Rigging.

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This feature appeared in the July 2022 edition of Practical Boat Owner. For more articles like this, including DIY, money-saving advice, great boat projects, expert tips and ways to improve your boat’s performance, take out a magazine subscription to Britain’s best-selling boating magazine.

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