Travellers making use of a popular BC Ferries route are warned to make alternate plans if they haven't made a vehicle reservation.

The company had planned to bring another major vessel, the Coastal Inspiration, to the route between Horseshoe Bay and Departure Bay to help shuttle passengers over the long weekend. The route is expected to be extremely busy Thursday and Friday as passengers make their way to the destinations where they'll spend Canada Day.

But the ferry needed a propeller hub repair. The work was scheduled to take place ahead of the long weekend, but a problem with the repair means the vessel won't be back in service until at least Monday.

As a result, BC Ferries is asking those travelling by vehicle to avoid the route between West Vancouver and Nanaimo if they don't already have a reservation. Those who need to use the route are asked to consider travelling as a foot passenger, taking public transit or getting a ride to and from the terminals instead.

Alternate suggestions include travelling on days other than June 28 and 29, and opting for sailings earlier than 9 a.m., which are generally less busy.

Saturday, June 30 is expected to be busiest in the morning, and Sunday, July 1 is likely to be the least busy day for travel.

The company has added a 12:30 a.m. sailing from Horseshoe Bay, scheduled to arrive in Nanaimo in the early hours of June 29 and 30.

Anyone who had reservations that have been cancelled will be notified by email, and their fees will be refuneded.

"BC Ferries regrets that it will not be able to move customers to the next available sailing, as reservations are near capacity for all sailings."