New type of propller that is 20 percent more thrust

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laurie65

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I AM LOOKING FOR A SMALL COMPANY THAT wants to help get this propeller going I have tested it on a 2ton lifeboat and the test did show that it is 20 per cent more efficient in thrust and speed I have contacted the university of Newcastle Emerson cavitation tunnel and there can do the tests on this propeller , that does save fuel and give more speed and trust I have got film of the test that I carried out to date.....
 
before you give all the secrets of this propeller away, have you covered the appropriate design registration, name, and/or patents issues ?

I'd go carefully to protect your IP rights.
 
Welcome!

While the forum is not really a place to seek sales/investment I think your product is at least 'boaty' not something blue Pfizer sell so good luck.

Your prop sounds truly revolutionary (no pun) a little too good to be true without evidence though. Do you know about theoretical hull speed? to increase that by 20% would be amazing.

The picky ones here will be grinding their (not there) teeth about presentation/grammar/spelling/punctuation. You only get one attempt at a first impression! Get someone to proof read before posting, especially if you are pitching to investors.

If you are in the NE, have you seen all the props Parsons tried for Turbinia? http://en.wikipedia.org/wiki/Turbinia

N
 
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NickRobinson said:
Welcome!

While the forum is not really a place to seek sales/investment I think your product is at least 'boaty' not something blue Pfizer sell so good luck.

Your prop sounds truly revolutionary (no pun) a little too good to be true without evidence though. Do you know about theoretical hull speed? to increase that by 20% would be amazing.

The picky ones here will be grinding their (not there) teeth about presentation/grammar/spelling/punctuation. You only get one attempt at a first impression! Get someone to proof read before posting, especially if you are pitching to investors.

If you are in the NE, have you seen all the props Parsons tried for Turbinia? http://en.wikipedia.org/wiki/Turbinia

N
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wHAT I NOW KNOW THAT I HAVE TESTED THIS ON A 2 TON LIFEBOAT THE BOATS OWN PROP WAS 16 INCH X3 BLADES MINE WAS 15 INCH X3 BLADES THE BAR IS ABOUT THE SAME SIZE ON THE TESTS THE BOLLARD PULL GIVE THE FIGURES 180 KILO FOR THE BOATS PROP MINE WAS 220 KILO BOTH THE PROPELLERS WHAT ARE CALLED OPEN.. as you say true good to be true, i have video and photos of the test, so these do prove the fact that it does work nick..
 
A single test like that is interesting but certainly not conclusive. If the new prop simply matched the engine better than what had been fitted before then a 20% improvement may be entirely predictable. Did you record engine revs for both props?
I'm not saying that that is what happened, just that one test is far from enough to be sure.
 
laurie65 said:
wHAT I NOW KNOW THAT I HAVE TESTED THIS ON A 2 TON LIFEBOAT THE BOATS OWN PROP WAS 16 INCH X3 BLADES MINE WAS 15 INCH X3 BLADES THE BAR IS ABOUT THE SAME SIZE ON THE TESTS THE BOLLARD PULL GIVE THE FIGURES 180 KILO FOR THE BOATS PROP MINE WAS 220 KILO BOTH THE PROPELLERS WHAT ARE CALLED OPEN.. as you say true good to be true, i have video and photos of the test, so these do prove the fact that it does work nick..
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Bollard pull is only one of the measures of a propeller's efficiency and not particularly reliable predictor of overall performance. Just saying a 15" propeller gives a higher bollard pull than a 16" is meaningless on its own. An effective propeller is one that is matched to the engine and the boat so you cannot just take propellers in isolation. A 20% increase in bollard pull does not translate into a 20% increase in speed.

To get any meaningful indication of improvements you need to start from a known base - that is a specific engine boat combination with optimum standard prop, carry out a whole range of runs in different conditions and at different revs plus tests of stopping power and reversing. Then repeat with your new propeller and note any differences. Having carried out many such tests on various designs of propellers I can assure you it is very frustrating trying to identify real world improvements across all the range of performance criteria. BTW a 2 ton lifeboat is probably not the best type of boat to use for comparative tests!
 
Tranona Yes this lifeboat had a 12 hp diesel at 1800 revs into a 2 to 1 gear box the book speed of this boat is given in the handbook 6 point5 knots the revs using its own prop was 180 kilos and 6/4 knots on the GPS.. the revs was 874 RPM.. that prop had 12 inch of pitch 16 inch by 3 blades My propeller give a bollard pull of 220 kilos at 849 RPM and did well over 7 knots this prop as 13 inches of pitch, so it just needs a degree taking of to match the revs I have been in contact with the NEWCASTLE university and there have told me that there can do the tests in the cavitation tunnel that is why i'm looking for a person or company that can come into this with myself as this would and can save fuel and money by increasing speed and thrust for the same power..
 
There is something very odd about your figures. If the revs you are quoting are engine revs then both propellers are wrong. The correct size propeller should give you your maximum speed at very close to WOT - that is near to 1800 not less than 900. So are those figures shaft rpm?

If you want to do basic tests, calculate the size required for a normal 3 blade prop using one of the freely available calculators such as Propcalc on www.castlemarine.co.uk then carry out your range of tests as I suggested above. Then have a similar size propeller made with your new blade shape and run the same tests again. You then have some idea of whether any change is a result of the change in blade shape. In general there is little advantage in having a smaller diameter prop on a displacement boat unless there are space constraints, although there are marginal benefits of less drag.

With modern sailboats, speed per se is of little importance as the vast majority of boats can easily achieve maximum hull speed with standard propellers. The problems are usually around maintaining speed in adverse conditions and more importantly reducing drag when under sail. So most developments in recent years have been aimed at improving these areas of performance with folding and feathering blades and in some cases self pitching or adjustable pitch props.

Your current set up of heavy displacement boat powered by a low powered, low revving engine is not representative of the typical small motor boat. Most now use small high speed diesels with more than enough power to achieve hull speed using conventional 3 blade propellers. So would suggest if your target market is that sort of boat you use one for your tests.
 
Have you contacted the major universities who do marine stuff, Southampton and Plymouth come to mind and do a joint venture with them?
 
In fairness to OP if he is going to use Newcastle's cavitation tunnel then he is going to get some top notch testing done. Properly conducted sea trials can follow, but Newcastle are certainly well placed to do an engineering evaluation.
 
Rigger Mortice said:
In fairness to OP if he is going to use Newcastle's cavitation tunnel then he is going to get some top notch testing done. Properly conducted sea trials can follow, but Newcastle are certainly well placed to do an engineering evaluation.
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That's true if they're actually going to conduct the testing. Not so much if they're just renting him the tunnel for a day.

Pete
 
Tranona the engine is a sarb diesel rated at 1800 RPM INTO A 2 to 1 REDUCTION gear box=900 @ 12 HP this boat is well over 25 years old now and with its own prop gives only 874 rpm.. shaft speed. the same test with my prop give 849 rpm shaft speed plus both props work going astern them are as far as i can go by myself... BOAT DETAILS Weight 1/3/4 tons length 5/9 meters engine ga 12 HP SINGLE 1600PI 73 FOOT POUNDS propeller shaft 25 mm..
 
The minor difference in shaft speeds is neither here nor there - both are close to engine max revs. You would not expect much difference in shaft speed between a 16*12 and a 15*13 - they could both be equally effective as the 1" less diameter is offset by the 1" extra pitch (more or less).

As I said earlier if you are going to test your alternative blade you need to do it with otherwise identical propellers and with a type of boat engine combination which reflects what is in use. No modern small boat uses shaft speeds that low, but most are in the range of 1500-1800 rpm and would have a propeller much smaller than yours for 12hp.
 
Rigger Mortice said:
In fairness to OP if he is going to use Newcastle's cavitation tunnel then he is going to get some top notch testing done. Properly conducted sea trials can follow, but Newcastle are certainly well placed to do an engineering evaluation.
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True. Would be intresting to see the maths behind the new shape.
 
Are you saying the boat is 5.9m long and you're achieving well over 7 knots? Doesn't sound right on a displacement hull.
 
I was told that when manufacturers make a propeller the pitch they use is a compromise and is deliberately pitched at not maximum thrust. I had asked a marine engineer about putting a larger propeller on my boat before last and he pointed out that the problem with a bigger propeller/different pitch was that in a boat at tick over it would be difficult to control in a congested marina. And on my last boat the owner had gone for the 4 blade prop instead of the 3 blade prop consequently at tick over 800 revs the boat was doing 5 knots. And I hate going in and out of gear while manoeuvring.
 
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