Most warships have one, permanently assigned crew. Personnel rotate on and off the ship, but a core complement remains throughout a deployment. Keeping one crew on station more than 12 months, however, often results in poor morale and a gradual deterioration of training. These conditions often require a long voyage back to the United States so that the crew can rest, take on replacements, and schedule shore-based maintenance.

The idea of rotating crews on a deployed surface warship rather than sailing it home was the subject of experimentation on small U.S. warships starting in the mid-1990s. Rotating crews allow for longer deployments and more rest and training time. Crew rotation also avoids some trans-oceanic voyages that inflict wear and tear on ships and their components.

The U.S. Navy has a mixed record of rotational crew use. Ballistic missile submarines have operated with rotational crews for decades with great success. Rotational crew employment in the smaller vessels of the U.S. surface fleet, however, has seen a mixed record of successes and challenges.

Now a number of close U.S. allies have embraced this concept. The U.K. Royal Navy, the German Navy and the French Navy have begun using rotational crews, or plan to implement the concept. Denmark has used rotational crews for some time with an overall positive effect.

Rotational crews have become increasingly common on the larger, frigate-sized ships of their fleets. The German Navy is planning to use rotational crews on its F125 class frigates in order to support their presence forward for longer periods. The French Navy is purportedly planning to use rotational crews to support the overseas deployment of its FREMM frigates. The Danish Navy has used rotational crews for its ice patrol frigates for many years, and the French navy rotates crews on its Antarctica icebreaker L’Astrolabe.

The Royal Navy’s Type 23 frigates are employing crew rotation in order to keep a ship deployed on station in the Middle East for an extended period. HMS Montrose, the Royal Navy frigate recently involved in deterring the seizure of a tanker by the Iranian Revolutionary Guard, is in fact now manned by the crew of one of her sister ships, HMS Monmouth, currently in long-term maintenance.

Though the use of rotational crews is on the rise, allies have experienced some difficulties in their implementation, especially in periods of crisis. HMS Montrose must soon come off task in order to again swap crews, despite being in the midst of an active operation. The Royal Navy had to dispatch another surface combatant, HMS Duncan, to carry on Montrose’s patrol mission.

The U.S. surface fleet has experimented with rotational crews for almost a quarter century, beginning with mine warfare and patrol coastal ships. Additional experiments with simple crew swaps aboard destroyers of both the DD-963 and DDG-51 class took place in the early 2000s. The Navy has tried the Horizon system, which uses three or more crews for at least two ships, in addition to the more traditional blue/gold rotation, where one crew is on the ship while the other is training and preparing to come aboard for the next cycle. The littoral combat ship was originally designated with a 3-2-1, multi-crew “Horizon” plan but was switched to the more familiar blue/gold crew system following a series of engineering casualties in 2016. The Navy also plans to use blue/gold crew rotation on the future guided missile frigate (FFGX) class.

The U.S. rotational crew experience has drawn a mixture of support and criticism. Analysis by the Congressional Budget Office suggested long-term costs to the Navy could be reduced as rotational crews allow for a smaller overall fleet. One critique of rotational crews, however, cites increased maintenance costs for ships deployed overseas for long periods versus those based in the U.S. Other opposition seems couched in “tradition” and past deployment practices. Some elements of the surface Navy do not want rotational crews because it means a major cultural shift in how sailors live and work at sea and ashore. They believe sailors work best when assigned to one ship where they can develop an intimate knowledge of that vessel’s equipment and characteristics.

Criticisms and traditions aside, the shrinking size of Western navies since the end of the Cold War and the growing list of missions for which they are responsible suggest that some method must be found to keep more ships deployed and ready for active missions for longer periods. The alternative is buying more ships and hiring more sailors. Few nations, including the U.S., seem ready to embark upon 1980s-style fleet building programs such as the 600-ship Navy that was intimately connected to the U.S. Navy Maritime Strategy of the Cold War era. Until such a time returns, Western navies must consider less costly solutions. For the moment, the particular solution that seems to be catching on among more navies is rotational crews.