A beer cooler for a sailing boat was created on the basis of Peltier elements. These elements cool the air within the container, the other surface of the elements has been cooled with the seawater. The critical question was that the Peltier elements work not long if they undergo very frequent switching. It was solved with the introducing of a delay between every switching events. In addition a special forecasting regulating algorithm was implemented to echieve the sertain precision of regulation.