Caledonian Maritime Assets Limited (CMAL), which owns the ferries and ports used by CalMac, said the state of the linkspan’s ropes was a safety concern.
Morven Bridges, head of engineering, said: “We understand islanders will be concerned about the impact on lifeline ferry services.
“We are working closely with CalMac and our contractor to minimise disruption as far as possible and certainly to ensure there is no delay in the replacement work programme and the linkspan returns to service no later than Saturday 8 October.”
Lifting ropes on the linkspan at Barra’s Castlebay Ferry Terminal also need to be replaced.
CMAL said measures were in place to allow for the continued use of the pier and dates for the repairs would not clash with Lochboisdale closure.
