These heavy displacement hulls include such craft as tugs and deep sea trawlers. If you study these boats in profile you will notice that the stern rises above waterline. The mid section of the hull is very full and the midsection is deep in the water. The chine and buttock lines will reveal the full bellied shape usually present in this type of hull. The heavy displacement hull has to be able to carry great loads and in the case of tugs, be able to get a great grip on the water in order to do its job properly. The "hull speed" of this type of vessel is generally less than that of other types.