I hope the following helps. Prior to 1873, when Continuous Service became compulsory in the Royal Navy, men were free to move between the merchant fleet and Royal Navy. This meant a man could enter the RN for the duration of a ships commission and when paid off look for alternative employment in either service. Continuous Service itself was first introduced in 1853, and if a man signed up he was paid an extra penny per day. Service records for those men who signed up for CS can be found on the National Archives (NA) website.
If you know the name of a RN ship served on then it is possible to use the Ship’s Description Book at the NA to find information on place of birth, age and previous RN ships served on. If you don’t know a ship, but believe he was awarded a medal, you could look at the medal rolls, find likely matches, then search each ship’s description book – for someone called Richard Smith this would be quite a task, but possible.
If he served during the Crimean War then there were two possible medals awarded, the Baltic Medal and the Crimean Medal, the latter could have ‘battle’ clasps, for the RN these might be Azoff, Inkerman, Balaklava and Sebastopol. Only men in the RN were awarded medals, not those merchant seamen who delivered war material.
Martin