Introducing the Teignbridge Clamp on Blade Propeller
The Teignbridge Clamp on Blade (CoB) propeller is an innovative, UK patented and worldwide patents pending, replaceable blade propeller designed for operational flexibility and maximum hydrodynamic efficiency. The CoB propeller has been developed in partnership with the Energy Technologies institute as one part of a 3-year, multi-million pound development and demonstration project focused on improving the efficiency of ship propellers with the aim of reducing fuel consumption and associated greenhouse gas emissions.
The CoB propeller is suited to a wide variety of applications including merchant, commercial, military and leisure vessels and can be supplied in a wide range of sizes from 0.75m to 5.50m diameter with keyed of hydraulic shaft fitting. A 5.5m diameter propeller can be packaged and transported in a 20ft shipping container.
With a hub diameter ratio typically only 5% higher than a mono-bloc, fixed pitch propeller, the patented blade clamping design represents the lowest hub to diameter ratio, replaceable blade propeller on the market. This ensures that as much of the propeller disc area as possible is put to work generating thrust. Unlike alternative, radially bolted solutions, the CoB propeller hydrodynamic efficiency is further improved by minimising the number of bolt heads present on the hub surface resulting in improved flow over the hub.
In the event that propeller blades are damaged, vessels can be trimmed by the bow to make the propeller accessible, enabling blades to be replaced using a barge & crane rather than having to use a dry dock or slip the vessel. This feature of the system saves the time and cost of deviating to suitable port facilities that may be hundreds of miles away. The modular design provides an economical and flexible option for smaller vessels and superyachts – individual blades and hub components can be carried by a diver for propellers up to a diameter of 1.20m, further improving the logistics of transporting, storing and installing/replacing blades.
The increased ease with which propellers blades can be changed also means that long-term changes in vessel use profile can be matched with a revised propeller design, improving efficiency, reducing emissions and saving fuel with rapid return on investment for the customer.
The component parts of the CoB propeller are fully CNC machined to ensure dimensional accuracy in the initial assembly and interchangeability of replacement blades. This means that operators can carry a single, replacement blade instead of a full replacement propeller, freeing up deck/engine room space.
The CoB has been developed and tested using Teignbridge Propeller’s purpose-built test vessel – HRV1 to validate in-house coupled computational fluid dynamics and structural simulation work. HRV1 is equipped with state of the fibre optic load measurement technology to monitor propeller thrust and torque as well as vibration analysis. Additional in-house destructive physical testing has been used to further validate the structural integrity of the concept.