The term 'Ship Sealer' can be summarized as a person who applies TAR to the exterior of ships. TAR is a waterproofing material that helps protect the ship from the elements. It is applied in a thin layer and is often used in conjunction with other materials such as paint or varnish. The job of a Ship Sealer requires a great deal of skill and precision, as it is important to ensure that the TAR is applied evenly and without any gaps.