davidfox
Well-Known Member
When i grease mine, it is full of old grease, i wouldnt think it would matter if you did it every 3 years, but obviously it depends on use
Could the Brunton autoprop be what I need?
- Thread starter cmedsailor
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When i grease mine, it is full of old grease, i wouldnt think it would matter if you did it every 3 years, but obviously it depends on use
davidfox
Well-Known Member
I use a shaft anode as well as the auto prop one and my prop one lasts 2 years and would probably last 3 but i chicken out, the shaft on the other hand gets changed avery year
NormanS
Well-Known Member
With the anode, it is well worth while putting a dab of paint on the anode just where the nylon retaining screws are. It stops the zinc at the screws eroding, and the anode falling off.
I have greased mine every year, takes about 2 minutes, but the grease which comes out* has always looked perfectly clean, so I don't know how necessary it is.
*To grease the prop you take out two screws. Into one, you screw in an adaptor for a grease gun, and excess grease comes comes out from the other one, repeat for each blade.
Someone mentioned fitting a "standard" anode instead of the expensive Brunton ones. Tell me more. Which anode do you recommend?
I have greased mine every year, takes about 2 minutes, but the grease which comes out* has always looked perfectly clean, so I don't know how necessary it is.
*To grease the prop you take out two screws. Into one, you screw in an adaptor for a grease gun, and excess grease comes comes out from the other one, repeat for each blade.
Someone mentioned fitting a "standard" anode instead of the expensive Brunton ones. Tell me more. Which anode do you recommend?
charles_reed
Well-Known Member
A little difficult - the Brunton, fitted 21 years ago, originally to a 2GM20, instead of a 2-blade fixed prop - is now on it's second engine.Hi Charles, I'm considering to switch from fix-pitch to Bruntons. U say u burn 1.3 l/h when motorsailing, could u estimate (recall) your consumption with fixed blades? And what is your boat & the engine?
All I can say is that there was an immediate increase in speed under sail of about 15%, but the mists of time obscure the precise improvement in fuel consumption.
The boat is the original pre-production Parker 31 prototype, the current engine is the 3YM20.
Motor-sailing, I never have to use an rpm of more than 2000 - usually this gives me about 5.8 knots through the water - the engine easily reaches max rpm of 3600 to give 7.6 knots in still water.
My fuel consumption, measured between tank refills and over 1845 hrs has been between a maximum of 2.08 litres (a F7 head wind through the Rion and down to Korinthos @ 2600 rpm) and 1.03 litres an hour beating up against the meltemi through Dodecanese and Cyclades when the engine was only used to and from anchoring.
As I've said, trying to justify the additional capital cost by a DCF of fuel saved is probably a mug's game.
Going back over old logs - maximum tankage-limit with the 2GM and fixed prop was 24hrs; I now work on 35hrs, but with a different engine as well as the Autoprop. Tank is a nominal 12-gallon tank. 1.55 to 2.27 litres and hour. The 30% improvement is probably not far off the mark, but my way of sailing the boat dramatically different.
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olddog57
New Member
I contacted the SD, after a couple of emails they confirmed, that their adjustable pitch actually means 3 pre-set positions (ahead, astern, feathered): "... yes the propeller has ahead astern and feathered. You can not change the pitch of the propeller whilst underway"
Which means you cannot have any benefit of variable pitch, nor to have simultaneously RH & LH prop, but you can pre-set ahead/astern pitch very precisely (and differently), and going astern you still have the same leading edge (as the blades may swivel about 180) - gaining better astern performance and short stopping distance.
I don't buy this options for £2389.00 + VAT (my boat needs 20" prop)
olddog57
New Member
Thank you very much, Charles, for the report: this is convincing enough
Tranona
Well-Known Member
That is a common arrangement for feathering props as it allows the prop to be adjusted to suit different boats rather than having different blades to achieve different pitch. There are very few variable or controllable pitch props available because of the complexities of making them work. Both Max Prop and Gori have what are known as "overdrive" props where you can change the pitch once to reduce engine revs at cruising speed. They are, however hugely expensive.
The Bruntons Autoprop is the only prop that automatically adjusts pitch according to load and speed and as several people have reported that gives advantages when motor sailing, so is popular for people who do long distances in this mode. However, for many people the aim is to reduce drag when sailing and achieve at least the same motoring performance as with a fixed prop. This can be achieved much more simply and cheaper with either a folding or a straightforward feathering prop. The individual has a choice depending on what their objectives are.
olddog57
New Member
Thank you!
I am very new to this world (especially to motor-sailing or motoring - my only prev experience were engine-less sailing boats 24" up to 40")
Now I study this topic as I have a Fisher 34, and my aim should be clear.. Will, probably, re-prop with Bruntons
Pagetslady
Well-Known Member
I bought a very old one last year and have been using it all this year, I have a Westerly Corsair 36 which had a 2 blade prop, the difference is amazing for the same revs I get 1knt faster in smooth sea when motoring stops quickly although there seems to be a second or so when it seems to do nothing but then the prop get hold same when going astern can be a problem when going astern as speed does increase rather. As for sailing I think I get a full knt extra in similar wind and sea conditions. I am installing a new Beta 35 this winter so I have to get another Brunton as the beta goes the opposite way to the VP2003 so I shall be selling my old one I paid £350 for it last year of a bloke who was installing a beta into his boat.
However mine is one of the very old ones that has ball bearings rather than the new ones that have rollers and they can be greased, so mine do rattle when engine is ticking over I have to put gearbox in neutral and increase the revs a little, as for removing prop walk why is this an advantage propwalk was the best thing about my old 2 blade prop, if you learn to use it it makes coming alongside so easy, but I have now found that the Autoprop does have propwalk if used carefully. Bruntons have quoted me £1900 for my new one.
Regards Mike
However mine is one of the very old ones that has ball bearings rather than the new ones that have rollers and they can be greased, so mine do rattle when engine is ticking over I have to put gearbox in neutral and increase the revs a little, as for removing prop walk why is this an advantage propwalk was the best thing about my old 2 blade prop, if you learn to use it it makes coming alongside so easy, but I have now found that the Autoprop does have propwalk if used carefully. Bruntons have quoted me £1900 for my new one.
Regards Mike
