Sea Service Pistols are Holster or Belt sized pistols that are distinguished by being largely made of brass and having a side clip on the body of the pistol that allows the weapon to be hooked to the owner’s holster or belt. On land a dropped pistol is an inconvenience. At sea it can be a financial loss if the weapon goes overboard. These pistols are made in either Dog Lock or Flintlock styles.
Note the clip in the top picture.