Ferry operator Caledonian MacBrayne has confirmed that it is to transfer its ship crewing operations to Guernsey.
Caledonian MacBrayne's ferry routes are currently out to tender
The firm believes the move will save more than £1m a year in National Insurance contributions.
A second subsidiary company will be established at the current Gourock base, which will be responsible for administrative and operational staff.
CalMac says it needs to cuts costs if it is to successfully tender for the Clyde and Hebrides ferry routes.
The new offshore crewing company is expected to come into being in February.
CalMac said the move would not affect the pay and conditions of staff or lead to redundancies.
Lawrie Sinclair, managing director of CalMac, has written to all staff informing them of the decision and a 90-day formal consultation on the plan has begun.
His letter states: "CalMac has identified a management company based in Guernsey which can provide the corporate and administrative structures and services required to proceed with the proposed change to an off shore employment company for all of CalMac's sea-going staff.
"The company, which would be a subsidiary of Caledonian MacBrayne Ltd, would be known as CalMac Crewing (Guernsey) Ltd and would be based in Guernsey.
"The contract that would be entered into would be between Caledonian MacBrayne Ltd and Clyde Marine Offshore Ltd, which is part of the Glasgow-based Clyde Group."
Mr Sinclair added: "The arrangement detailed here enables Caledonian MacBrayne to offer an appropriate company and contractual structure, recognising the fact that these proposals are currently being progressed under the consultation process which is due to continue until the end of January 2006."
However, Angus MacNeil, Scottish National Party MP for the Western Isles, said more than 200 CalMac workers who live in the isles were worried about the move.
He added: "This is bad news for the people of Scotland and for my constituents - it leaves users, crew and the islands no further forward."