Winter on the water. Part 1

We are coming to that time of year again when life onboard ‘Ambassador’ has to change.

As the outside air temperatures fall, my saloon windows regularly drop below dewpoint and condensation gathers.

There are two solutions to this problem; one is to keep the cold surfaces above the dewpoint temperature, the other is to reduce the amount of water vapour in the air.

Changing my diet and removing boiled things (and obviously, cups of tea) would reduce the water vapour in the air but I happen to enjoy the odd cup of tea, and pasta too, so last year I looked at the single glazed windows to see what could be done there.

Since the winter contains more dark than it does light, and the cabin lights were generally on when I was onboard, restricting what little light there was would not be a problem so I covered the outside of the saloon windows with two layers of bubble wrap.

The results were almost instantaneous, the cabin warmed up and the diesel-fired blown-air heater turned itself down; and the following morning there was no condensation to wipe off.

This initially seemed good, but one has to think a little deeper; since I didn’t change my diet and reduce the water vapour in the air, where did the condensation go?

As the winter took control and snow and ice lay on the foredeck, I went into the forward cabins to check all was well and found out exactly where the water vapour had gone.

The inside of the un-insulated windows were crusted in a heavy layer of ice and this gathered on the window frames and the surrounding woodwork too; in fact, it had coated most of the bunks and well as much of the contents stored underneath. Pretty much everything above the waterline had some ice on it in varying thicknesses.

But how and why did it get there?

In the extremities of the boat, the blown air heater runs out of impetus and the air that reached the forward cabins was barely warm, and certainly not warm enough to overcome the cold.

The air intake for the blown-air heater is in the saloon and it took the warm air (moisture laden from cooking and from life itself) and transported it to the far reaches, where it promptly condensed on the cold surfaces and froze.

Had the saloon windows been left un-insulated, the bulk of the water vapour in the galley and the saloon would have condensed on them instead – as it previously did.

The windows act as a condensing dehumidifier, albeit with a wipe to remove system, rather than with a bucket to empty.

Whilst this is an inconvenience and is unsightly and laborious, it is clearly preferable.

Good as this is, better solutions are available and as this winter draws in I will implement them and see what improvements can be made - Watch this space!