A short-term charter of the MV Arrow is expected to earn the Steam Packet about £250,000.
The ferry operators have leased the vessel to provide additional services on the Stornoway-Ullapool ferry route in Scotland.
The Arrow will operate a number of overnight freight and passenger sailings over the peak summer period.
It comes after operators, Caledonian Macbrayne (CalMac) faced trouble with disruption and breakdowns.
A CalMac spokesman said: " “The chartering of the MV Arrow will help provide much-needed resilience at a time when COVID restrictions remain in place and there is high demand for spaces on board our ferries".
Managing Director of the Isle of Man Steam Packet Company, Brian Thomson, said it is vital ferry operators help each other in times of need.
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