A replacement ferry brought in last week to serve an island off Newfoundland's northeast coast has broken down.

The Sound of Islay, which was put on the run to the island of St. Brendan's in Bonavista Bay, was pulled out of service Saturday when it developed troubles with its gearbox.

The Sound of Islay is one of the older vessels in Newfoundland and Labrador's aging ferry fleet.
(CBC)

The ferry is being repaired at the dock in Burnside.

Residents of St. Brendan's have been told to expect delays in the ferry schedule for at least four days.

The Department of Transportation, which will try to provide another ferry, started offering helicopter service Monday morning for St. Brendan's residents who needed to get on and off the island.

The Sound of Islay is a member of Newfoundland and Labrador's aging ferry fleet, which has been flagged as dangerously outmoded.

A consultants' report released in early October found that the average age of the province's fleet is 33 years. The Sound of Islay, which usually works on routes involving Little Bay Islands, is 39 years old.

The Newfoundland and Labrador government has begun work on replacing some of the ferries, and last week issued contracts for design work on two replacement vessels.

The consultants' report recommended replacing at least eight vessels as soon as possible.