Primarily gyrojet weapons, due to their nonexistent recoil, and versatility via ammunition types that boil down to 'put holes in people' instead of 'poke holes in the hull'<br/><br/>(Gyrojets are weapons that 'kick' a bullet, which then fires an internal rocket engine to accelerate; no recoil, same bullety mess downrange except at arm's reach, because it needs time to accelerate)<br/><br/>Also, personal sidearms do exist, and the vast majority of those are generally analogous to modern Pistols, in both automatic, and revolving-chamber flavours, depending on the owner's preference.<br/><br/>Also, everyone gets basic knife training just in case close-quarters combat does occur, as the idea of facing down a large, angry person with a foot-long knife tends to mitigate most boarding actions very quickly.<br/><br/>Also, engineering has a supply of Hydrazine-fuelled blowtorches that, with a few modifications, can be converted into makeshift flamethrowers with an approximate ten-metre range.<br/><br/>Of course, the marine detachment aboard the ship also has access to large weapons, including Rifles and shotguns, though, in the case of ship-to-ship boarding actions (which occasionally happen), shotguns are the preferred weapon due to reduced penetration into the ship's bulkheads, while still retaining effective penetration properties against 'softer' targets.