Sealift is a term used predominantly in military logistics and refers to the use of cargo ships for the deployment of military assets, such as weaponry, military personnel, and materiel supplies. It complements other means of transport, such as strategic airlifters, in order to enhance a state's ability to project power. A state's sealift capabilities may include civilian-operated ships that normally operate by contract, but which can be chartered or commandeered during times of military necessity to supplement government-owned naval fleets.
Sealift shipping falls into three broad categories: dry cargo freighters, liquid tankers, and passenger ships. During joint operations, dry cargo ships may transport equipment and supplies required to conduct and sustain the operation; tankers carry fuel; and passenger ships carry troops to the theater and allow the evacuation of noncombatants or those in need of medical aid.
While ships are slower than their airborne counterparts and may require port facilities to unload their cargo, their larger hauling capacity allows them to transport heavy armoured forces or bulky supplies that only the largest strategic airlifters (such as the C-5 Galaxy) could normally handle, and in much greater quantities.
Some smaller navies have built multi-role vessels that combine a frigate or patrol vessel role with a sealift capability. The Royal Danish Navy and the Royal New Zealand Navy HMNZS Canterbury being two examples.
Typically two types of ships are used, the older less seen cargo ship and the more usual tugboat. While both types also haul barges, the cargo ship also carries cargo on deck. Most Arctic communities do not have a port and cranes to unload the supplies but may have a simple dock. Where the community does not have a dock, the ship either must ground itself or the barges. Supplies are then removed by forklift truck which is also carried on board. The interior of the barges are used to carry fuel and other supplies are carried in containers on deck.