Condensation

A subject close to every boaters heart. It does of course settle on any surface subject to a change in what I will call 'supportable humidity'. This appears mostly as misted up windows where the air at ambient temperature and humidity meets the cold glass at which point the air in the immediate vicinity of the colder glass can no longer support the moisture in it and hence 'dumps' it.

However this condensation doesn't only happen on windows and for some years now we've been plagued by the side of our double bed mattress getting damp. Only our double bed mattress you note - the two singles and the dinette never have suffered. We tried cork tiles down the side (sort of worked but stained the sheets), we tried pulling the mattress out every day and allow it to dry each day (hard work and obstructs the corridor) and we asked all of our boaty friends.

In the end we worked out that the damp was coming from condensation formed on top of our toilet holding tank, which as you may remember from earlier pages is just about the entire underneath of our fixed double - in fact all that separates our mattress from the poo tank is a sheet of wood. What was happening was that the 'contents' shall we say of the holding tank was going in warm, but as the holding tank is effectively the bottom of the boat, soon got cold. Air circulating around the remaining space under the bed is of course warm - courtesy of the assorted heating systems on board. Warm air meets cold metal = condensation.

Went down to B & Q (other purveyors of DIY materials are available) with the idea of buying enough tins of expanding foam to cover the tank. Looked at the cost - changed our minds. Went looking for polystyrene roof tiles - found them - too thin. Wandering around the store stumbled into the builders area and came upon massive sheets of it - good 1 inch thick, compliant with assorted building regs and used as wall insulation. Did some measuring, bought 1 slab a bulk pack of silicone tubes and 1 tin of expanding foam. went home.

Cut the slab with a Stanley knife (other brands are available) to size, then stuck it on using nice big zigzags of silicone. Awkward areas got covered in the expanding foam.

No more condensation on the bedding.

A bit of a drip

Some weeks ago now we noticed that from time to time, at approximately 45 minute intervals the water pump that pressurises our system started to cycle. By 'cycling' we mean that the pressure switch noticed a drop in pressure so switched the pump on until this was resolved - typically around 1 second or so). This as always down to one simple cause - there is a water leak somewhere between the pump and the assorted taps and outlets. We worked out that every time the pump cycled 1 pint of water was going somewhere. Now that may not sound a lot but just try filling a pint jug with water and dropping it on your floor at home and then do this every 45 minutes or so and see how much mess it can make. The problem we had was that there wasn't a mess. We knew there was a leak - it just eluded discovery.

One morning as I set off for work our youngest crew member mentioned from deep down within duvet land a dripping noise in the cupboard but I figured he had been dreaming and didn't realise the significance of this discovery. Later in the day the noise, now we knew where to listen for it became easier to locate and we ended up taking off the wall panel that covers the heating system header tank.

A strange and to this day unidentified gloop had formed on top of the header tank water - kind of like blamanche. This weight of this was stopping the ball valve in the header tank from getting to the top of it's travel so a slow but steady trickle was getting into the header tank. This of course went down the overflow pipe and ended up in the bilge - that's why we couldn't find where the water was going.

We stirred up the gloop with a well placed finger, used a drill powered pump to suck out the contents of the header tank, refilled it, mashed up the remaining gloop and pumped out the tank once more. Threaded a small plastic pipe down the overflow pipe to clear it of gloop and the problem is now cured.

Took the opportunity to re-locate the water pump isolating switch from deep within the cupboard to a much more sensible wall mounting in the kitchen - another job done.