Moisture aboard a ship is not only dangerous, it is inevitable. For this reason it is important to know and know how to protect our boat from its worst effects. If our boat does not maintain the optimum level of humidity, on the one hand it can affect the condition of the boat (producing corrosion, oxidation and even mold), but on the other hand it can also affect people and give health problems such as arthritis or rheumatism

humedad en barcos


Humidity is the manifestation of water evaporated in the atmosphere and condenses when sudden changes in temperature are found.

A cubic meter of air at a temperature of 25ºC supports approximately 4,000 grams of water in solution. But if we cool the air mass until it reaches 15ºC it will only admit 2,000 grams. Therefore, we will have 2,000 grams of water that, in the form of drops, will come out of the solution to be deposited on the cooler surfaces of the ship, such as crystals and metal parts. Depending on whether this temperature decrease is more or less accentuated, these drops will fall and slip accumulating in the bilge.

humedad a bordo


With regard to our boat, we must worry, especially, of two situations in particular:

If the moisture condenses on any surface where there may be traces of organic material (remains of unwashed food or body fat on upholstery) it will become the ideal breeding ground for the appearance of mold.

But moisture tends to condense on the metal parts. All our navigation instruments, especially the electrical connections, have metal parts. If we take into account that in the air there are dust particles and mineral salts in suspension and that, when dissolved in water they can act as a conductor bridge, we will understand that, after a few days we can find the discharged battery.

That is why it is important to carry out a good maintenance.



To fight against humidity it will not be necessary to take our boat to a dry dock, but it is important that we take certain measures. In this war against moisture, these are the products that will help us:


If we leave garments on board it is convenient to put them in plastic bags (after making sure they are well dried) with small sacks of cloth with silica salt or any desiccator composed of hygroscopic material. If we do not have these materials, common salt works very well.

In the bilge we can also place a container with cooking salt (better if it is fat salt) or a dry ball that can be found in drugstores.


The petroleum jelly will serve to completely cover the contacts of the navigation instruments. It will protect them perfectly, even the parts that come into direct contact with the water.


Alternative to Vaseline very efficient since the silicone is not conductive. In the open it offers protection for just over six months. So inside it will be something superior.


If it is not possible for us to ventilate the interior of our boat regularly, it is important to use a portable dehumidifier that will keep the boat dry and with an optimum level of humidity.

There are on the market portable dehumidifiers specially designed for enclosed spaces that, in addition to eliminating the humidity of carpets, cabinets and mats, also contribute to the disappearance of bad odors.

And you already know that if you need a dry dock in Barcelona or you want more information about these topics, you only have to access the website of V de Bravado.

This post is also available in: Español