Beating Condensation – Keeping the water outside the boat.

The biggest problem we have encountered with our experience, so far, has been the dread build up of moisture known as condensation. Everywhere I have lived (in houses) has had some degree of condensation but now we are in a smaller space it’s that much more noticeable. But how do we beat mouldy shoes, drips on heads, damp bedding and (my worst enemy) clogged up salt shakers? Well let’s see….

Air Flow

Condensation has a habit of forming where the air is static, this is because surface has been allowed to cool to the outside temperature and the gaseous water is able to transfer it’s kinetic energy to said surface and become a lower state molecule. In laymans terms; if the water molecule hold more energy (heat) than the surface it was cease becoming a gas and will revert to a liquid.

By increasing air flow around the boat the surfaces (e.g. windows etc) will be more likely to retain the ambient temperature. Air flow also reduces the effects of moisture in enclosed spaces (such as lockers).

In order to do this I am looking at installing low amp computer fans (costing as little as 11p) around in strategic positions around Pinafore, anywhere there

Small low amp CPU fans can increase airflow and cost as little as 11p

could be an enclosed space fans will be installed. This includes cabins, lockers and vents to the outside.

Reduce the number of surfaces

The second approach to reducing condensation is to reduce the number of surfaces on which it can fall. This is where carpeting comes in. Not on the floor but on the walls and ceilings.

This will be done in the cabins, where people frequently sleep. It’ll be sad to lose the nice white headlining in these areas but it will provide a warmer drier area to sleep in, and that is the goal.

We also plan to introduce some kind of covering to the windows either by shutters or by using suction cups attached to some foam (removable). This should create an airspace between the window and the interior hopefully keeping the boat a little more insulated at night.

Look familiar? Caravan carpet lining should reduce the area condensation can form

Whilst we on the subject of surfaces it may be worth mentioning that dry matt bedding will help solve the problem of mattresses going mouldy. It is essentially a honeycomb structure that allows air to flow below the mattress and carry away excess moisture.


It seems to me that one of the most common misconceptions is that heat reduces humidity and therefore condensation. Unfortunately it’s not that easy (I wish it were!); heat will remove water from windows and the like. but all it is doing is increasing the amount of water that can be held in the air and therefore humidity. Don’t get me wrong, heat will help, but as soon as the temperature falls it will return just as before. The secret here is to pump in warm dry air whilst removing the damp air. We will be installing a diesel powered warm air system, providing Pinafore with much dry, heated air.


There are two schools of thought on dehumidifiers that I have encountered. Those who will sing their praises to the ends of the Earth, and those who will

You needn't spend much on a dehumidifer. This 10L model from B&Q was relatively cheap but came top in Yachting Monthly

insist that they just don’t work on a boat and that it’s a pointless waste of electricity. We decided to go with the former school of thought since we figured it could do no harm. After all; the ways of actually removing the moisture are very limited (air flow to the outside being another way) that we’ll take all the chances we can get.

Any comments you may have would be very gratefully received; I will keep you updated with the progress and the success (or not) or the work over the coming months.


2 responses to “Beating Condensation – Keeping the water outside the boat.

  1. In Cote d’Ivoire we encountered humidity (& mould) and put rice in the salt cellar. This may help!

  2. hello thanks for the infomation.

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