Inventors revolutionise boat propeller system
Sun, 09 Sep 2012 6:12p.m.
By Shaun Summerfield
A couple of Southland blokes reckon they've found the holy grail of boating.
They've invented a propulsion system that combines the best features of a water jet with those of propellers. It means boats are more manoeuvrable and able to travel further and faster on less fuel.
It's environmentally friendly and could be used in everything from speed boats to super tankers to submarines.
They haven't reinvented the wheel, but Barry Davies and Paul Patterson have come pretty close.
“We think it's a pretty big breakthrough,” says Contrapel inventor Barry Davies.
That’s a typically Southland-style understatement from a man who is about to turn the whole idea of a boat's propellers quite literally upside down.
“The Contrapel system is a propeller system working above the waterline,” he says. “So most boats have a propeller that's exposed underneath.”
But that is only half of the story, because what makes Contrapel so special is that there are two propellers spinning in opposite directions.
It's not the first time New Zealanders have come up with alternatives to the propeller. Sixty years ago Bill Hamilton invented the jet boat – a go-anywhere craft that revolutionised river travel around the world.
The Tuatapere teacher was looking for ways improve his own jet boat nearly 20 years ago when he chanced on the idea of counter-rotating propellers.
Since then the team have almost pumped rivers dry trying to perfect the system.
Today’s 10-metre rescue boat is the culmination of two decades of hard work, Invercargill company Stabicraft happy to share in the pioneering project.
“We started with something that people looked at quite strangely and we thought it can change the mould of boating,” says Tim van Duyl of Stabicraft Marine. “If these guys can change the mould of propulsion then we'd like to be a part of that.”
Essentially, Contrapel combines the best of the jet systems and conventional propellers. Not only do they say it is more efficient, but the enclosed system is also safer and better for the environment.
“The dangers are vastly reduced,” says Mr Davies. “You will not damage the riverbed or bottom of the lake because the water is not pressurised coming out of here.”
With a patent secured, Contrapel is being released to the world, and the US Military are already looking.
“It will actually work all the way up to huge ships,” says Mr Davies. “It works equally well underwater for submarines. We want this technology to be uptaken all over the world and used in every facet of marine propulsion.”
And this is only the initial thrust. Mr Davies and Mr Paterson are already perfecting a version that allows the propellers to oscillate.
The accidental discovery, the result of faulty shaft, nearly doubles efficiency, making the boat faster and more economical.
Tests have shown the same system can also be used to generate electricity.
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11/09/2012 11:42:20 p.m.
Peter Wright wrote:
Fantastic, congratulations. I cannot wait to be able to fit one to a small boat so that I can use it on rivers in South Africa. Jet boats are banned in SA due to enviromental reasons, however I have always though they were better than open props if used respectfully.
Roll on with production!
11/09/2012 11:41:43 a.m.
Brilliant people don’t come around that often, Barry with all those years behind you someone needs to bottle your thoughts so we don’t lose them for future generations. Well done indeed!
11/09/2012 7:48:57 a.m.
Good on ya Barry! You have been working on these things for as long as I have been alive and it is great to see your work getting to this stage. Go Tuatapere.
11/09/2012 12:43:10 a.m.
Excellent Invention guys! Congratulations on your hard work and continuous perseverance over the two decades. Ultimately you have done it and have proven that there is a better jet propulsion system. Your family's and your sacrifice is now coming to fruition after those many long years and it is great to see that it has come to be realised within your lifetime. My sincere best wishes to the two inventors and particularly to my dear friend Barry whom I have known for some 23 years.....who is a typical Southlander Kiwi, very intelligent bloke yet very humble and excellent human being whom I admire and respect for his ingenuity and perseverance.
Another worldwide useful technology contribution from a Great Nation New Zealand.
With Love and Best wishes for your success on the world stage.
10/09/2012 3:43:16 p.m.
Counter rotating ideas have been moving forward in many areas.From the helicopter which has no tail rotor, to some pumps that have been using 2 impellors for decades.This does look a good improvement. It uses partly the idea of a incased propellor, which reduces the waste of the traditional propellor. It also uses more propellors. In the jet research they have been working with counter rotating turbines for over 50 years, so moving boat propulsion forward from what has remained basically unchanged for 100 years is a good step. If 2 is better than 1, is more better still? I haven't followed the jet research to know if they progressed down that line, but they have definately used 2 turbines as early as the 1950's.The oscillation sounds weird, and it may be the larger of improvements if they can reliably control it.If it works in water, it should work also in power generation for hydro dams, even sea generation, as the sea turbines I've seen also seam to be one turbine, even if multiple turbines are mounted in-paralell. It will probably also apply to wind turbines, where smaller turbines could harness more wind with smaller turbines. From the jet side, multiple turbines tend to be quieter, so it may also reduce the noise from wind turbines.Maybe the same idea could get more generation out our existing carbon free dams/wind for cheaper power?This probably falls under the NZ high-tech, a growth industry for NZ. We need more like this.
10/09/2012 2:05:24 p.m.
Fantastic invention. There are real disadvantages to both the jet and the propeller. This answers both!
10/09/2012 12:45:06 p.m.
Excellent new's indeed and to uphold the NZ tradtion, I hope there is a bit of number 8 wire in there somewhere. James, I think Kiwi is pushing your buttons, he is just trying to be funny in a non humourous way.
9/09/2012 9:14:51 p.m.
I think thats a brilliant invention, coupled with the Hamilton Jet Boat, this is sure to a major financial earner for its inventors so they can research other ways to improve the ways people live their lives for the better. @KIWI, change your attitude and Maori might actually be interested in conversing with you otherwise they will just read the first sentence then switch off as though you're not even worth thinking about.
9/09/2012 9:06:43 p.m.
Neil Obrien wrote:
One day it may become another National asset sale.Share to foreigners only,as there wont be any Kiwi!s left in their own country.
9/09/2012 7:59:17 p.m.
Sorry guys the artificial movement of water is covered by the Treaty of Waitangi and Maori invented this concept 100 years ago anyway - it just got lost somewhere. So you will need to negotiate with Maori re appropriate Koha and discuss with Iwi when and where this can be used in NZ and at what cost and then of course there will be the Taniwhas to deal with!
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