Welcome to my blog. Here you will find the journeys of Ti Gtu and information that I have researched and found useful for maintaining and servicing yachts and motorboats.

I post full information that I find on the Fay Marine information site, accessed through www.faymarine.com/ and I can be emailed at paul@faymarine.com.

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Happy sailing,

Paul Fay

Friday, 20 January 2012

Lavac sea toilets

I have been contacted by our old friend David T who has a Lavac sea toilet. These use a Henderson type bilge pump for emptying. David has found that hydrochloric acid attacks a small piece of aluminium in the pump. (see his reply) What David does is to strip the pump and use a domestic loo cleaner to clean the parts.
I did not realise that there were aluminium parts
 in these pumps, I do have one somewhere and will check but think that the fairly recent version I have is all plastic.
Worth checking if you have a Lavac!!
Another method of keeping the system clear of calcium is to use vinegar. This is considerably more expensive and not as aggressive as hydrochloric acid so may well be OK where there are aluminium parts in the system. Used in a similar fashion to the acid it should help to stop the calcium build up and the need need to regularly strip the system.
As far as I am aware all the normal heads such as the almost universal Jabsco plastic pump type only have stainless parts.
Some years ago I tested all these stainless parts from an old loo along with some 304 and 316 bolts by leaving them in 50% strength acid. After 3 days I examined them under a powerful magnifier and found only a slight dulling but no corrosion.
Our current Jabsco is around 6 years old and has not needed the valves or pipes cleaning yet.


  1. I have an older Lavac in fresh water currently, but we are fitting out for extended ocean travel. I have heard that these otherwise excellent units can suffer from over-aggressive cleaning and to use vinegar. You can buy acetic acid (the "acidic" part of vinegar and only about 5% by volume) at 100% concentration and dilute it yourself for economy, but if you can collect and tank rainwater, a good method for Lavacs is to (carefully) plumb in a Y-valve to your seawater intake line and to give the whole system a freshwater rinse. This will kill the "critters" that may otherwise colonize the more attractive bits of real estate and will, with the acid treatment, move the debris back to its mother, the sea.

  2. Thanks Rhys, I agree that vinegar can be used and is probably best in a lavac due to the metal parts mentioned by David. I have not come accross the acetic acid for sale here but it may be available.
    The collecting rainwater just for the heads is a bit complicated for me and if i was collecting rainwater I think I would save it for drinking.
    Intrestingly, I have just surveyed a yacht that I built 24 years ago. In that I put in a toilet bowl with an outlet pump like a lavac but added a small inlet pump as well. This meant that the seat seal is not needed. Still working fine after 24 years!!!