Kitsap Transit’s oldest foot ferry, Carlisle II, will be out of service several months for an overhaul that could cost $1.2 million. The vessel serves the Bremerton to Port Orchard foot ferry route.

The scope of the overhaul is still being developed, Kitsap Transit said, but agency officials believe the main and upper decks will need replacement, as well as refurbishing the tanks that hold fuel and potable water. Kitsap Transit’s newest foot ferry, the M/V Waterman, will replace the Carlisle II as the primary vessel on the route.

The 150-passenger Waterman will be the first hybrid-electric ferry to commercially operate on the Puget Sound. Once the Carlisle II returns to service, it will become a backup vessel on the Bremerton to Port Orchard route.

The Carlisle II is 102 years old and is the oldest continuously operated vessel from the Puget Sound Mosquito Fleet era when numerous small passenger-only ferries crossed the Sound, transporting people and goods before the advent of the automobile era and the large auto ferries, Kitsap Transit spokesman Sanjay Bhatt said Thursday.

The vessel was purchased in 1936 by Horluck Transportation and was used on the Bremerton-Port Orchard route.

“It played a vital role transporting workers to the Puget Sound Naval Shipyard in Bremerton during World War II,” Bhatt said.

Kitsap Transit purchased the vessel in 2003 and overhauled it in 2004. The Washington Commission for the Humanities has designated it a floating museum.