Ship & Boat International: eNews July/August 2019
Propulsion specialist Teignbridge has launched a new modular propeller concept, designed to enable users to swap individual blades instead of having to remove and repair the entire propeller. The gist of the ‘Clamp-on Blade’ (CoB) concept is that operators carry spare single propeller blades and simply remove and replace damaged blades as they sail. The CoB propeller's blades can be mailed by box or standard container.
Teignbridge says: “Many vessels will be able to carry spare blades and, if required, trim by the head to make the propeller accessible and replace the blades using a barge and crane, rather than having to use a dry dock. Vessel owners only need to carry one or two spare blades, rather than a spare propeller, saving space and cost.”
The CoB is manufactured in aluminium-bronze and no oil is used in the system. Teignbridge tells Ship & Boat International that the CoB boss is “much smaller” than that of a conventional ‘bolt-on blade’ model, which should equate to increased efficiency. “The CoB can be retrofitted to any shaft,” the manufacturer confirms. Each blade is CNC-machined for accuracy, balance and a close tolerance fit. “Spare blades will therefore be a perfect replica of the originals,” Teignbridge adds. The blades are held in position with a clamp and a Superbolt tensioner. The modular concept will also enable users to swap the CoB’s blades to best suit the vessel’s current activities and environment. Different configurations can be selected depending on whether the vessel is engaged in winter or summer work; in free-running or towing mode; or operating at high or low speeds.
The CoB has undergone finite element analysis (FEA) and destructive testing, plus sea trials aboard Teignbridge’s test catamaran HRV1, and class society approvals are expected later in the year. “Initial interest has come from vessel owners with fleets operating in regions where impact damage has occurred due to debris in the rivers and sea areas,” the company reveals.