Serco Denholm, the firm which operates tugs and barges in Plymouth's Devonport Dockyard in support of the Royal Navy, is cutting 57 posts.
The firm says the cuts are as a result of efficiency measures.
Unions have said they are considering industrial action.
Serco Denholm said it expects to make 43 redundancies at Devonport, with a further 14 jobs going though natural wastage.
The jobs are among more than 100 expected to go nationwide.
It is hoped the redundancies can be achieved through a voluntary early retirement scheme.
The firm said the cuts were a result of efficiency measures rather than issues relating to the workload at Devonport, which last week led to the announcement of 240 job losses at DML, the company which runs the dockyard.
Serco Denholm will meet with union leaders on Wednesday to discuss the cuts.
Cutting overheads
The Transport and General Workers' Union (T&G) has said it will fight the move and has threatened industrial action.
Last week, DML said its 240 job cuts would take place over the next six months.
DML partly blamed the need to cut overheads following soaring costs of submarine refits at the yard.
The yard employs 4,800 staff and is Devon and Cornwall's largest private sector employer.
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