The Dreadful Affair of the Backfiring Toilet (A Dad and John Story)

It was February 1997 and we'd just made our first transatlantic crossing to Tobago in the West Indies.

Dad and his partner had flown out to spend a few days in paradise, it was perfect, but for Dad it was to be something he later described as 'the worst experience of his life' .. let's talk toilets ..
 
The personal challenge of every sea toilet, their raison d'etre if you like, is to suck clean water in and fire dirty water out. Every toilet knows that for it to be 'high performing' it must never reunite the operator with the contents.

So, the principle of a sea toilet is fairly straightforward but in practice they are quite complicated little monkeys that require love and attention. Fail to give them this and there can be dire consequences.

A toilet (SL400)
One of the biggest issues is that the toilet is below water level so far from needing to encourage water to come in, you're actually trying to constantly stop it from sinking your boat. The flip side is that to get rid of the bad stuff you need a fair head of pressure to push out into the deep-blue beyond. This is typically delivered through a mechanical hand pump.

To make sure that nice water and bad water always flow in the right direction sea toilets have a necessarily complicated system of valves, syphon-breaks and sea cocks. Malfunction or abusive operation of any of these is likely to have an unpleasant impact on the effectiveness of the toilet.


But lets get back to the good ship Songbird. Her toilet was a Simpson Lawrence 400, a classic in the world of sea toilets and a good friend - we'd bonded the first time I stripped her down and the relationship had strengthened over time as I got to know her every valve, spring, nut and washer.

A joker valve
But, despite this unhealthy intimacy one thing I never managed to get to work well was her siphon break.  Now this is bad news because what it means is that when you have used the heads water carries on flowing into the boat with potentially dire consequences. We solved this by having a simple rule .. you ALWAYS shut the sea cock after use. Of course you MUST also remember to open the sea cock before you pump out because otherwise the contents of the loo can't go anywhere and you run the risk of developing considerable back pressure.

Now the last bit of the toilet equation is called a joker valve. These are simple little rubber non-return valves that only allow the water to go one way .. unless under extreme back pressure in which case they catastrophically invert. This is a key point. Hold it in your minds ..

Lets get back to paradise. The good ship is gently rocking at her anchor outside a golden beech. We're sitting out in the sunshine supping a beer and watching the world go by. Dad pops down to use the heads and catch up on Chapter 17 of his Tom Clancy novel.
 
A few minutes later there's a 'whoooooosh' from the heads followed by a groan. Such was my relationship with the toilet that I sensed rather than knew what happened ... a high pressure toilet backfire.
 
The chain of events was simple but devastating. Dad had fully utilised the toilet as he browsed a good few pages of his novel. He then went to pump out but made the mistake of not opening the outlet sea cock. 
 
An Icelandic Geiser
He started to pump to evacuate the contents of the toilet ... when nothing happened he pumped harder and with more vigour ... still nothing so he pumped even harder. The effect was catastrophic.
 
With every stroke of the pump the pressure behind the valve increased, just like pumping up a tyre or charging an air rifle. Once it reached a certain point the joker valve could hold on no more and with a faint sigh of exasperation it simply gave up, instantaneously inverting and releasing all the built up pressure in an almighty blast. The contents of the toilet were projected upwards and outwards with the energy of an Icelandic geiser.
 
I rushed down below ... 'are you alright Dad? After a deathly hush I heard the muffled response and the words I hoped never to hear 'stay back .. the toilets exploded'.
 
An hour or so later we were supping a medicinal cocktail. 'Anyway'  I said trying to raise crew moral just a little 'at least you had your mouth shut' ... he gave me a resigned look. I said no more. Shit happens.

Next in the 'Dad and John Series' .. the Affair of the Lost Mind
 
Post a Comment