Composting toilet passes the test

Does a composting toilet really work on a boat? Wendy Smith gives the verdict.

In the March issue of Cruising Helmsman Wendy wrote in detail of how she and her partner Paul installed an Airhead composting toilet on their Westsail 32, Kabuki.

Wendy has just emailed this update for CH and mysailing readers on how the toilet is working “out there”.

“We thought we would send through an update on the composting toilet now that we have been using it fulltime for about 10 weeks,” Wendy said.

“We have found the toilet to be successful for us, and we are pleased that we purchased it. The length of time for each batch has not met the expectations quoted in reviews by users as 1-2 months (either we eat too much, or they used on-shore facilities as well!).

“We have found that a batch lasts between 3-4 weeks, then the unit is full and needs to be emptied. We have emptied in existing composting toilets, and our own composting bin at home. We also could empty over the side when over three miles out, or put it into the landfill collection.

"We have not noticed any odours, apart from the smell of composting soil. Paul finds emptying the solids tank a lot more pleasant than when we had a Porta-Potti.”

Tips and tricks Wendy and Paul have discovered:

“Be aware of too much moisture. Our first batch became too moist due to us adding to much water and not using the coffee filter liners.

“Experiment with your coir peat bricks. The bricks that I purchased here in New Zealand at the local hydroponics shop only took 1 hour to hydrate. Also we have found that putting a quarter of the brick in the unit and then adding a handful of peat after each donation worked better for us than using a whole brick on start-up.

“Make sure you empty the urine pot regularly - it fills up at just the wrong time.

“Our vent is on the port side of the hull, just under the rubrail. We developed an airlock after sailing on the starboard tack for 24 hours.

“The fan/vent only draws 0.1 amps, so we are able to cope with that with our solar panels."

Wendy said apart from these things the unit was quiet, odour free, with no pumping and no worries about blocking pipes.

“I am really happy with it, Paul was a bit disappointed with the length of time between empties, but about one month of fulltime use is not too bad. And it is nice to have a reasonably clear conscience about the environment.”

Wendy and Paul's story - giving a step-by-step description of how they installed the Airhead composting toilet and costs etc -  is in the March issue of CH, still available at newsagents nationally.

- Caroline Strainig