Navy shore establishment used to train merchant seaman . At the Royal Navy 's only establishment for Merchant Seamen , HMS Gordon , which takes the form of rambling buildings on dry land , with a pier , men from 19 to 41 are put under Naval discipline , given naval uniform and taught seamanship before they even board a ship . These are men who , when they registered , expressed a preference for the Navy and have been posted to the Merchant Navy . Trainees hauling a bulk of timber from the hold of the ship .