VESSEL REVIEW | CFAV Canso – Harbour/firefighting tug to support Royal Canadian Navy's east coast operations

The Royal Canadian Navy (RCN) recently took delivery of a new ship assist tug built by Ocean Industries of Isle-aux-Coudres in Quebec.

CFAV Canso is named after the Canso Strait, which separates Nova Scotia from Cape Breton Island. She has been classified as a large harbour tug (YTB).

The tug arrived at Canadian Forces Base Halifax in December 2025. She has just completed undergoing additional sea trials, testing, and crew training.

Canso is the first new YTB on Canada's East Coast and the third in the class built to replace the Royal Canadian Navy’s ageing Glen-class tugs. All YTBs were designed by Vancouver-based naval architecture firm Robert Allan Ltd (RAL).

“These new tugs are smaller to fit into close quarters and have a significantly greater bollard pull,” Evan Gatehouse, Project Director and Senior Naval Architect at RAL, told Baird Maritime. “They also have Fifi capabilities, which allowed the navy to retire its two Fire-class fire/rescue boats.”

Gatehouse said that from the original contract of four tugs awarded in 2019, the RCN recently awarded the builder a contract for two more vessels, which will provide greater redundancy in service.

Built to assist large ships and barges

“Their primary mission is ship-docking of navy vessels including the large new Protecteur-class replenishment ships, and have a secondary role in towing barges, smaller vessels like the Orca- and Kingston-class. Eventually, the new submarines Canada is procuring will be handled by these tugs, too.”

Canso has an LOA of 24.4 metres (80.1 feet), a moulded beam of 11.25 metres (36.91 feet), a draught of 5.1 metres (17 feet), a bollard pull of 50 tonnes, a speed of 12 knots, and accommodation for six crewmembers. Two firefighting monitors and a Furuno radar are also fitted.

“The RCN needed her to carry 10 tonnes of potable water, in addition to having an extra aft deck winch and a stern roller, a hold-down clamp and tow pins for open ocean towing of their smaller vessels, all while possessing a lifetime weight growth margin,” said Gatehouse.

“Icing load was also a factor. All of these added to the weight of the vessel so we had to watch our vertical centre of gravity so the final tug had sufficient stability. In addition, we needed to reserve deck space for portable skimmers and their gear as well as a power pack for oil spill recovery.”

Bespoke platform to suit naval requirements

Gatehouse remarked that Canso was a true multi-purpose tug, as she also possessed firefighting and pollution response capabilities.

“This was to be a copy of an existing type of vessels,” he told Baird Maritime. “No custom or new designs were allowed. The RCN went to Turkey to see another version of this tug to understand what the designer and the builder were proposing. They then could add anything they learned there to their original specification.”

Being a navy vessel, the tug had to have some unique additions. Gatehouse's favourite addition was the very complex exterior steel box to store 12 flares to navy requirements. It was complete with exterior sun shields, temperature and humidity sensors, and a water connection to flood it in case of emergency, similar to a full weapons magazine.

The two main engines are MAN 12V175D-MM units each rated 1,860 kW (2,490 hp) at 1,800 rpm. The emissions required are IMO Tier III, which in turn required emissions treatment in the engine room.

The Z-drives are Schottel SRP 430 FP units with fixed-pitch propellers. These have an integral ‘zero to idle’ slipping clutch. The shaft line utilised RAL’s now fairly typical straight line shaft with no cardan shafts.

“It’s a quite conventional and well proven ASD tug propulsion system, though MAN engines have not shown up in our tug designs very often,” said Gatehouse.

The tug also features a dedicated printer and computer with removable hard disks to provide a log of alarm warnings and machinery parameters.

“A pelorus used for taking bearings is not typical of small tugs but needed a space in the wheelhouse. Additionally the RCN operates with a ship’s engineer in the wheelhouse, so the service needed a second seat at the consoles to monitor the equipment.”

The forward towing winch is a standard ship docking tug winch with a fibre rope. Gatehouse said, however, that most 24-metre ship docking tugs do not have aft winches with long tow wires for open ocean towing, along with a stern roller and tow pins.

“We are just now investigating adding some more fendering on the stern bulwarks. The crews manage barge tows from the stern where the freeboard is lower to connect, and there has been a request from operators for a bit more protection of the tug in this area.”

Incorporating appropriate design elements not typically seen in naval vessels

Gatehouse said that, as the RCN had not bought a new tug in nearly 50 years, there was no institutional knowledge about modern tugs.

“We had to do a bit of education to pass on our ideas of how tugs should be outfitted and operated,” he told Baird Maritime. “Thankfully, the navy personnel were happy to listen to our ideas, even if not all of them suited their methods. We had a very good relationship with the navy personnel and their naval architect during our part of the work.”

Some of the navy’s NATO seakeeping requirements were more suited for a large surface combatant, and not really able to be fully achieved with a much smaller tug. According to Gatehouse, “after a bit of give and take,” the navy accepted that the tug’s performance in rougher seas will be naturally limited by crew comfort.

“Similarly, the original noise requirements were well suited for a large ship but not practical with a high-powered tug. Again, we compromised on what was reasonably achievable and allowed a bit more noise in the spaces right in front of the engine room in particular.”

Adapting to supply chain challenges

Gatehouse explained that Covid was the main challenge encountered during the construction of the first two YTBs, as it impacted the builder’s ability to purchase equipment as supply chains were impacted and general isolation requirements were in place. Meanwhile, for Canso and CFAV Stella Maris, the fourth YTB in the class, their respective deck structures needed to be redesigned because the winch manufacturer was forced to cease operations. As the new winches did not align with the existing deck foundations and structure, this necessitated changes.

For the builder in Quebec, two of the tugs had to be shipped to British Columbia. A lack of heavy lift tonnage at the time of delivery meant they made the journey on their own hulls.

For Gatehouse, the fact that numerous examples of the RAL 24-metre tug were in operation with civilian customers is an indication of the soundness of the design.

“Having a vessel class in service (where about 50 were in service when the contract was awarded) does help an owner feel confident that the design is a good one.”