Repairs to a lifting bridge that has been closed to traffic since August will begin next month.
A half-tonne bearing has been manufactured for Poole's Twin Sails bridge after it developed a fault.
Bournemouth, Christchurch and Poole (BCP) Council said work to install it could not begin until the completion of dredging works at the end of November.
It said that although repairs would mean the bridge could reopen, further work would be required.
BCP chief executive Graham Farrant said: "We fully appreciate the inconvenience and frustration of the Twin Sails Bridge being out of use.
"We are dealing with a very complex structure that is reliant on precision engineering and located in the challenging working marine environment of the harbour."
Earlier this month it emerged that Poole Council, which was abolished in April, had spent nearly £1.3m keeping the bridge operational since it opened in 2012 - more than half a million pounds more than budgeted.