Teignbridge Propellers teams up with Plymouth University
Fri, 30 May 2014
As engines have increased in horsepower providing greater power for the same size and weight, cavitation and how to overcome it has become a major issue for propeller designers.
As such Teignbridge Propellers has developed its C-Foil propeller, designed to enable vessels to achieve higher speeds – 35 knots plus - without incurring cavitation.
The company, which exports more than 90% of its propellers and is expanding its sales in countries such as Brazil, asked Plymouth University to carry out independent testing and analysis of the propeller, comparing it to the Wageningen B-Series propellers.
“We noticed we were getting more speed than competitors in like for like conditions,” said Teignbridge Propellers sales and marketing director Mark Phare. “The testing showed the C-Foil produced 10% more thrust and 12% more efficiency when compared to a standard prop design.”
While the C-Foil was initially developed six years’ ago, this is the first time independent testing has been carried out, with cavitation tunnel testing due to take place in June with Newcastle University.
“We’ve started to move forward with field testing, approval and validation,” explained Mr Phare. “This is the first time there has been a direct comparison with other propellers.”
And he explained that the C-Foil uses an anti-cavitation blade section which not only gives a higher protection from cavitation but also increases performance.
“The propeller is not made from a standard existing design or pattern,” added Teignbridge’s Alex Stevens. “The blade area, camber, blade section, and pitch, are used to optimise and produce the bespoke propeller for each vessel’s application.”
And he explained that the usual method for the propeller designer to overcome the problem of cavitation is to move some of the blade thickness from the back-face of the blade to the pressure side or front face of the blade however this takes away the effectiveness of the blade to produce thrust.
Instead the C-Foil has an anti-cavitation wedge section, designed to overcome root cavitation and provide increased performance.
“The wedge section has no added thickness on the pitch-face and a gentler curvature on the blade back-face, and so, both face and back-face cavitation is avoided,” explained Mr Stevens. “The section is more efficient over the convention shape, with wash back, because a working pitch is maintained and the section is able to provide lift or thrust.”
The increase in performance is put down to the C-Foil design having a greater region of higher pressure across its pressure face, said the report from Plymouth University.
“It can be seen that the thickened root causes the trailing edge in the increased pressure region to behave as a bluff body as opposed to streamlined; thus giving rise to a reverse flow indicated by these comparative velocity vector plots,” said the report’s authors.
Over the last 18 months, new propellers such as the C-Foil have helped Teignbridge Propellers expand and take on an additional five staff. The company has invested more than £1m in new machinery and expanded its factory in Devon by 20% with plans for another extension for new office space well underway.
“Brazil is a country where we are particularly expanding,” explained Mr Phare. “We took on an agent over there 10 months’ ago and have already delivered propellers for six vessels with orders for another 14.
“We have been developing strong links and there are huge demands for quality products for the offshore support vessels. The shipbuilding industry is expanding after the discovery of oil and there is great potential over there.”
Visit Teignbridge Propellers International Ltd at this year's Seawork International on stand number B59.