Is a Bruntons Autoprop the only propeller to do what it does?

Otter

Otter

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I love the concept - self pitching, reduces revs and therefore consumption and noise. Feathers under sail adding a good half knot compared to our 3 blade monster.

However it requires me to sell a kidney in order to buy one, and I was saving that kidney for a new mast and sails. So is there anything available that will do most of what the Autoprop will do? The aperture on the CW only allows for a feathering not a folding. I think the Kiwi is a great concept but apparently throws blades on slow revving high torque engines like our 84hp 2200RPM diesel and I don't think fits on 1.75" shafts.

Really appreciate alternative ideas.
 
I am in the process of choosing a feathering or folding prop at the moment. I've looked at them all and just about decided that I'm going to stump up the cash for an Autoprop. Main reasons are mechanical simplicity, astern performance, and the fact that the blades feather independently if the flow isn't perfectly aligned with the shaft. Some feathering props can autorotate in those conditions.

A bit worried about talk of poor anode life in this thread though. http://www.ybw.com/forums/showthread.php?105178-Volvo-propeller-corrosion
 
Now discovered that the Autoprop needs a shaft brake because I have a PRM gearbox - ANOTHER £1400!
 
Colvic Watson said:
Now discovered that the Autoprop needs a shaft brake because I have a PRM gearbox - ANOTHER £1400!
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Go MaxProp or Featherstream, when you re engine its very easy to change the pitch & rotation.
My 2 bladed MaxProp is over 20 yrs old with no anodes & still in good condition.historically the boat has done about 100 engine hrs PA from new
 
I have two Autoprops fitted on a Maxim 380 catamaran fitted with 3YM30s + saildrives.
1. Revs are reduced under all motoring and motor sailing circumstances.
2. Sailing speeds feel faster although quantifying exactly how much is beyond my skill / experience.
3. She now tacks without having to back the headsail.
4. Stopping/reversing is brilliant. Spinning her with one engine in forward, the other in reverse needs to be done gently or crew end up on the floor.
5. The props vibrate differently and more than the fixed props and are definitely noisier motoring.
6. I wonder about the extra weight on the end of the sail drives and the longer term effect on the sail drive bearings. The props are appreciably heavier than the standard Yanmar fixed 3 bladers.
7. I have the full toolkit so servicing is straightforward (worth getting).
8. The anodes are useless even painting around the fixing holes or using plastic screws. I have only had 3-4 months use out of them. For that reason I acquired 2 Brunton retractable anodes to assist the whole sail drive/prop protection.
 
We went for a Kiwi prop. Our boat is 10m long keel ketch with a TMP gearbox, 2200rpm is our cruising speed (Perkins 4108). The Kiwi certainly improves our sailing speed and means that nine times out of ten we know which way she will kick when going astern; which to us probably makes the price well worth it. On the down side it does not stop shaft rotation, but it doesn't start until we reach 5kts. We have lost one blade in the seven years that we have had it, but that was down to electrolysis of the stainless steel pins; they now use Titanium which seems to have solved the problem.
Talk to Alan at Kiwi, a really nice guy who knows his stuff not a salesman on commission.
 
I suspect that with a Colvic Watson, you do a fair bit of motor-sailing. If this is the case, go for the Autoprop. You will find that when motor-sailing the performance is amazing. (Just a happy user).
 
I had an Autoprop for 25 years, before I had to replace the blades which cost more than the complete prop in 1990.
There is no other self-feathering prop which can claim to self-pitch as does the Autoprop - there are however a number (folders especially) which can improve on the drag exerted by the Autoprop.
Its biggest benefit, for me, has been its effectiveness when motor sailing and when I re-engined for one with a 22% more powerful engine, I didn't have to change it (or the gearbox), to still achieve the same hull speed.
 
Having now added the cost of the shaft brake - required apparently with a hydraulic box - the whole lot comes to £4,500 plus fitting, which in my financial world is utter insanity, those with deeper pockets will think otherwise. The Autoprop is superb for motorsailing and going astern but is has almost no affect on drag - a feathering prop versus a free spinning fixed prop is 0.25knots with more at low wind speed and less at higher wind speed, and the Autoprop is worse than that, it's not great at reducing drag.

So the Autoprop is a no no. Which leaves me trying to find something that sort of achieves what the Autoprop achieves but at a price that doesn't frighten the horses.

Currently considering an Axiom prop; gives better motor sailing performance than I have and waaaaay better stopping ability plus less noise and less drag - for £800. I don't mind spending a bit more to get nearer the Autoprop but not six times as much!
 
Featherstream is the best alternative. Will be a big improvement on fixed. You can adjust the pitch differently in forward and reverse. Talk to Chris at Darglow. He may well suggest a 4 blade. More expensive than 3 but cheaper than Bruntons.

If your kidney is a good match for me, though, I will buy you an Autoprop and fit it.
 
Colvic Watson said:
Having now added the cost of the shaft brake - required apparently with a hydraulic box - the whole lot comes to £4,500 plus fitting, which in my financial world is utter insanity, those with deeper pockets will think otherwise. The Autoprop is superb for motorsailing and going astern but is has almost no affect on drag - a feathering prop versus a free spinning fixed prop is 0.25knots with more at low wind speed and less at higher wind speed, and the Autoprop is worse than that, it's not great at reducing drag.
Where did you get the fact that the Autoprop does not decrease drag, I have had two on my corsair , and the difference in sailing performance between a fixed two blade prop and the Autoprop was around 1 knt faster with the Autoprop. I have also found a shaft brake made in USA which is around £400 http://www.shaftlok.com/

So the Autoprop is a no no. Which leaves me trying to find something that sort of achieves what the Autoprop achieves but at a price that doesn't frighten the horses.

Currently considering an Axiom prop; gives better motor sailing performance than I have and waaaaay better stopping ability plus less noise and less drag - for £800. I don't mind spending a bit more to get nearer the Autoprop but not six times as much!
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Hadenough said:
As we all have been! I often wonder what the lady in the superwoman outfit actually looks like? Sorry, serious drift.
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I have the saved old original
3680007054.gif


A shore leave ticket on here now :sleeping:
 
Colvic Watson said:
Having now added the cost of the shaft brake - required apparently with a hydraulic box - the whole lot comes to £4,500 plus fitting, which in my financial world is utter insanity...!
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I have a Variprop on my boat. Before we changed to a fully hydraulic drive we had a Perkins 4108 with a gearbox that allowed the propshaft to spin free regardless of the gear selected when the engine was off. We used to switch off the engine once the sails were up & then jump below, lift the cabin sole and stand on the propshaft to stop it from spinning. Once stopped, the blades would feather and all would be well.

With the Beta 50 and the hydraulic drive the prop feathers as soon as the engine is off (or indeed the drive is in neutral).

So - you may find a way round having to install a brake.
 
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