Space Marine chapters (and many renegades) operate three main types of voidships.

Battle barges (BBA) - These are the Astartes equivalent of battleships. Battle barges are slow and ponderous, but their ability to withstand punishment is legendary. They form the stiff backbone around which the rest of the flexible Astartes fleet operates. The only Astartes warship to have sufficient fire-power to trade blows with Navy capital ships. Teleportariums are standard. Typical Astartes contingent is 2-300 marines, but they can easily accommodate a full chapter of 1000.

Strike cruisers (CLS) - These are compact and heavily armoured light cruisers. They have great speed and tremendous defensive capabilities for something their size. Their primary function is to deliver Space Marine strike forces to ground and space targets. To this effect they carry numerous Thunderhawk assault ships, boarding torpedoes, and drop pods. Some strike cruisers have teleportariums, but this is increasingly rare. Typical Astartes contingent is 100 marines, but they can easily accommodate a full cohort of 500.

Assault frigates (FFA) - These are fast and heavily armoured frigates. Their primary tasks are to act as independent long-range scouts and Astartes fleet screens. In a secondary capacity they can be used for minor landing operations and hit-and-run raids. Typical Astartes contingent (if any) is 50 marines, but they can hold a full company of 100 if need be.

Typical fleet tactics involve scouting actions using assault frigates. If possible they will capture or disable enemy screens with lighting raids. Meanwhile a steady advance of one or more battle barges will keep the attention of the enemy's capital ships, while strike cruiser dart in on the flanks to take out key enemy vessels. Once the battle barges are within boarding range they will unleash a torrent of boarders to cripple the enemy's flagship. The best tactic against marines is keeping the range open, provided you have ships with the range. If you're defending an objective, such as a planet, this can be difficult - Marines will quickly cripple orbital defences and launch orbital strikes if they come within range of the planet.