Ship owners must ensure sure that all their seafarers are correctly certificated, their vessels are seaworthy and that their business is carried out in a safe and effective manner. The maritime regulatory authorities work closely with national and international partners in the shipping industry to promote the safe construction, operation and navigation of ships on behalf of the government and the DfT.
These industry bodies employ many ex-seafarers in a variety of technical and administrative roles. You may be able to work for one of these maritime regulatory authorities after moving ashore.
Find an outline of main sectors ashore here.