The hull of a boat that is heavily covered with marine fouling such as barnacles, algae and small shells will increase the frictional resistance and eventually the cost of fuel. These barnacles have to be cleaned from your yacht's hull. If your boat is a recreational one that is made of wood, check the stern and stem part. It has to be of streamlined form to reduce the water resistance.
A streamlined hull will reduce the frictional resistance of your boat, or yacht. In addition, if you feel that after cleaning and smoothing the hull surface of your boat and it is still slow while moving on the water, you might have to consult with a naval architect to assess the propulsion system that you install in it. The pitch of the propeller might be too small, or the blade area ratio is too large. If this is the case then you need to replace the propeller with a new one that is suitable to the displacement, block coefficient and hull form of your boat or yacht. by Charles Roring