wet from the inside out

dawncraft chronicles

wet from the inside out

signs of damp inside Dawn TreaderPHOTO: Signs of water damage on the hardboard – dripping on my bunk, if I wasn’t in it at the time I would be convinced the windows were leaking.

When I first bought my Dawncraft it had no insulation at all but was covered in navy blue office carpet – parts of it still are and some even worse brown carpet on bunk sides - two bits of which still exist years later. The reason for this was to stop the dreaded condensation. This issue never really occurred to me as I had more than enough leaks from vents, windows and anything else connected to the outside world to worry about a little damp from condensing water vapour. However, over the last few seasons I have noticed it getting steadily worse and my desire to stay warm may be the problem.

The first thing we installed was a Propex gas fired hot air recirculating heater for the only reason being it was all I could afford. Basically, this takes its oxygen from the outside world burns the gas and sends the exhaust back to the outside. A fan blows the boat air across a heat exchanger and the cabin warms up, any fumes etc. being well away from windows where they could creep back in. This heater is rated at 1800 watt but with the Dawncraft's ability to leak warm air through sliding windows, roof vents, door vents etc. it struggled to lift the temperature more than 10 degrees. Great if it’s five degrees outside, not so good if it’s minus five.

What was needed was insulation. First job was remove the plastic roof lining and stick a load of bubble wrap with reflective foil. I did notice whilst doing this the amount of condensation that was trapped behind the plastic, but ignored as it wasn’t much. Heater fired up and the boat seemed much warmer, indeed the cabin roof would often have frost on it but inside was a balmy 6 degrees. I noticed the odd drip from the edge of the roof lining, but a few well-placed bowls dealt with this. Finally one of the fluorescent roof mounted lights started buzzing and flashing on and off like Morse code – it was full of water, condensation water. Next job get all the wiring out from behind the roof and surface mount it or in conduit, and every light is now bulk head fitted with condensation loop on the wiring.

dawn treader moisture gathererPHOTO: Portside full-length drip strips and collection points – I got rid of the original table area. It took up too much room and director chairs are far more comfortable on board

What came next, I would not recommend doing. Desperate men can get absorbed with an issue and exclude any rational thought process, but it has worked. Basically, I drilled holes six inches apart through the plastic lining, gave each one a good squirt of expanding foam and then with a broom smoothed it all out until it set. The mark 2 version was even better - a sheet of ply held up with broom on top of the car jack. Feel free to try it but buy a disposable overall with a hood and cover everything in plastic. Don’t go back in the boat until its set and whatever you do don’t light the gas or any spark as the fumes are highly explosive. It really has worked, and the boat got warmer.

PHOTO: Starboard side, this was the worst area, water would collect on the work top. The thermostat is for the Propex heater and the 12-volt adaptor for when we are on shore power. A larger collection vessel has been installed, this is in the trial stage, but it worked.

However, the condensation on the windows became a real issue and I ended up drilling the drain holes out, trying to shift the puddles building up in the channels. This damp channel would soon grow moss, lichen and all sorts of colonising plants filling the inside with water. I cured this by using dilute Eco washing up liquid to reduce the surface tension and get things flowing.

I sleep up forward in the v berths with my feet under the bow and soon developed a new medical complaint called Dawncraft feet. The top half of my body was toasting with the heater, but my feet were minus five and damp – you guessed it - now the entire bow section was wringing wet as condensation formed on the deck head and surrounding hull.

Finally, the whole hull was covered with 20mm thick polystyrene sheet covered in white hardboard – more of this later. I spent hours cutting lath to support the polystyrene until I discovered 'no more nails' or equivalent. It stuck beautifully, though use plenty.

The first night on board with this extra insulation was bliss, warm feet dry warm bed - I even removed some winter clothing. However, I woke up one morning in a large damp patch. Your first reaction being a certain age is not the best especially after a congenial evening in the Barge Inn at Seend. I am pleased to report that inside the sleeping bag was still dry.

Opening the blinds revealed the front window absolutely saturated and dripping down on the shelf and running off on to me. Worse the hard board that I thought would not be an issue – I quote “if this gets wet I have worse problems” resembled O level chemistry chromatography paper.

condensationPHOTO: It's not pretty, but it's highly effective especially if I am not there for a while. Sadly all the panels are damaged by condensation drips and will need replacing. 

OK so what do I think has happened? There is a set volume of air inside the cabin which heats up. Warm air holds moisture in the form of invisible water vapour – even me breathing adds to this. Before I insulated everything in sight condensation probably formed evenly and thinly across the whole boat, but now the same volume of air with the same percentage water vapour condenses on the coldest surfaces – the windows. They used to mist up but never this badly. Even the internal aluminium channel covers on the window frames have beads of moisture on them.

I am in my “experimental development phase”. I can’t cure the problem, but I can engineer where the water goes, and a simple but effective solution came to me – Wiring conduit mounted under the window frames directs the excess moisture in to collection vessels. Basically, I cut back the carpet to the hull, cleaned it up and stuck the channel on with some special seal (anything any where grip adhesive goo). Within minutes of installing it dripping noises were heard and when I left the boat little drops of water were already collecting in it. It will also act as a flood channel for the sliding windows which have an ability to be overwhelmed by a decent rain storm and overflow.

Has it worked? The short answer is yes and after visiting the boat today and realising that I was collecting more than anticipated an adaptation with drain tap had to be fashioned to the original collecting vessel under the front shelf. All the window channels had water in which was dripping into various pots and tubs. Once we are through the worst of the winter then a more aesthetic version can be thought up for the front window but for now its saved the bunk.

PHOTO: The window channels filling with moss and lichen don’t help but its difficult to control - eco washing up liquid has worked but a good clean out with a flat bladed screw driver is the only real solution.