Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Rating: Thread Rating: 3 votes, 4.67 average. Display Modes
Old 15-04-2013, 11:54   #406
Registered User
 
Yachts66's Avatar

Join Date: Sep 2005
Location: In the Jungle, on an Island near the beach
Boat: Roberts 45 Mariah's Child
Posts: 654
Images: 15
Re: Autoprop ?

Quote:
Originally Posted by hellosailor View Post
Stainless is also damned expensive.
LOL have you checked the price of bronze lately??
__________________

__________________
We don't stop playing because we grow old, we grow old because we stop playing! Ben Franklin
Yachts66 is offline   Reply With Quote
Old 15-04-2013, 12:57   #407
֍֎֍֎֍֎֍֎֍֎

Cruisers Forum Supporter

Join Date: Apr 2006
Posts: 13,029
Re: Autoprop ?

Not that bronze is cheap, but "raw" stainless here is usually bar or sheet, while bronze is more likely to be had and worked in bulk, or from scrap, and cast into final shape. If you wanted a stainless prop with the same proportions, wouldn't you have to start with either a wicked strong forge, or carving out a terribly thick ingot?

And the folks casting bronze can always re-use their scrap, while the folks working iwth stainless have to sell their scrap back to a foundry, to have it remade back into sheet, etc. again. Way more expensive than just tossing your scrap back into the crucible and getting 100% use of the stock.

Eother way, I've only seen stainless on powerboat "blade" props, never on sailboat props with thicker cross-sections.
__________________

__________________
hellosailor is offline   Reply With Quote
Old 15-04-2013, 12:59   #408
Senior Cruiser
 
delmarrey's Avatar

Cruisers Forum Supporter

Join Date: Mar 2003
Location: Now in Blaine, WA
Boat: Modified Choate 40
Posts: 10,702
Images: 122
Re: Autoprop ?

Bronze is more malleable and EZ to repair. SS, once you start welding on it or it gets bent then it has to go to the heat treaters for stress relieving. Which costs and time consuming.
__________________
Faithful are the Wounds of a Friend, but the Kisses of the Enemy are Deceitful! ........
A nation of sheep breeds a government of wolves!

Unprepared boaters, end up as floatsum!.......
delmarrey is offline   Reply With Quote
Old 15-04-2013, 13:01   #409
Senior Cruiser
 
delmarrey's Avatar

Cruisers Forum Supporter

Join Date: Mar 2003
Location: Now in Blaine, WA
Boat: Modified Choate 40
Posts: 10,702
Images: 122
Re: Autoprop ?

Quote:
Originally Posted by hellosailor View Post
Eother way, I've only seen stainless on powerboat "blade" props, never on sailboat props with thicker cross-sections.
I have a folding 2 blade prop of SS.
Attached Thumbnails
Click image for larger version

Name:	SS_prop_open.jpg
Views:	88
Size:	94.3 KB
ID:	59259  
__________________
Faithful are the Wounds of a Friend, but the Kisses of the Enemy are Deceitful! ........
A nation of sheep breeds a government of wolves!

Unprepared boaters, end up as floatsum!.......
delmarrey is offline   Reply With Quote
Old 15-04-2013, 13:49   #410
Registered User

Join Date: Feb 2012
Posts: 2,441
Re: Autoprop ?

Quote:
Originally Posted by Dockhead View Post
Old kind had water-lubricated bearings. New kind you have to grease every time you haul out.

...There is nothing wrong in principle with water lubricated bearings -- your cutless bearing is water lubricated, and it carries vastly more stress than the blade bearings of an Autoprop, which don't spin around continuously like a cutless bearing, but just turn a little to allow the blades to feather.

.....
I think there's a world of difference between water-lubricating a bearing for continuous rotation at speed, where the rotation provides a hydrodynamic wedge preventing contact between the shaft and the bearing, and water lubrication of an essentially static interface where insufficient speed or rotation angle is developed to set up any such hydrodynamic effect.

I'm not weighing in on the merits of Autoprops in saying this, just making a more general point about the basis for cutless bearings: they're not intended, nor are they suitable, for intermittent or partial rotation. (Which is how they get away with using rubber, not normally a suitable bearing material due to the high coefficient of friction)

So I don't see that water lubrication can be vindicated in this situation by pointing at cutless bearings. It may be perfectly OK, but I think this line of argument is flawed.

and this:
<< With any other prop the fun would have been spoiled, grinding across at usual cruising revs. But with the Autoprop, it was possible to throttle down to about 1400 RPM where you almost couldn't hear the engine at all, and the boat was still cutting through the water at 7.5 knots. It was magical, and a memorably pleasant crossing. Not possible with any other kind of prop.>>

Hmm – how about a VP prop, like a Hundestedt?
__________________
Andrew Troup is offline   Reply With Quote
Old 15-04-2013, 14:40   #411
Moderator
 
Dockhead's Avatar

Cruisers Forum Supporter

Join Date: Mar 2009
Location: Cowes (Winter), Baltic (Summer) (the boat!); somewhere in the air (me!)
Boat: Cutter-Rigged Moody 54
Posts: 19,737
Re: Autoprop ?

Quote:
Originally Posted by Andrew Troup View Post
I think there's a world of difference between water-lubricating a bearing for continuous rotation at speed, where the rotation provides a hydrodynamic wedge preventing contact between the shaft and the bearing, and water lubrication of an essentially static interface where insufficient speed or rotation angle is developed to set up any such hydrodynamic effect.

I'm not weighing in on the merits of Autoprops in saying this, just making a more general point about the basis for cutless bearings: they're not intended, nor are they suitable, for intermittent or partial rotation. (Which is how they get away with using rubber, not normally a suitable bearing material due to the high coefficient of friction)

So I don't see that water lubrication can be vindicated in this situation by pointing at cutless bearings. It may be perfectly OK, but I think this line of argument is flawed.

and this:
<< With any other prop the fun would have been spoiled, grinding across at usual cruising revs. But with the Autoprop, it was possible to throttle down to about 1400 RPM where you almost couldn't hear the engine at all, and the boat was still cutting through the water at 7.5 knots. It was magical, and a memorably pleasant crossing. Not possible with any other kind of prop.>>

Hmm – how about a VP prop, like a Hundestedt?
Hundestedt props are fantastic, but few of us have boats big enough to use them. The smallest is for 150 horsepower; I've only got 100.

As to water-lubricated bearings - I know that lack of specific knowledge rarely holds anyone on here back from vociferously arguing a strongly held opinion , but I think I'm going to bow out of an engineering discussion which I am unqualified to carry on . Any arguments I might bring would be pure mental masturbation. I seriously doubt, however, that Brunton - a serious engineering company whose main business is making propellors and stern gear for big ships - made a fundamental design error in choosing the type of bearing to use in this very popular and very widely used prop, an error so stupid that guys jawboning on the forum have a better engineering grasp and would never have made themselves. And in fact, the thrown blade problem, which affected a limited number of props, was the result of a problem with locking washers, not bearings, and was the subject of a recall.

So no, I cannot construct an engineering proof of the suitability of water-lubricated bearings for this app,ication, but I have also not heard a serious argument against them which was more than idle speculation. I can imagine that there could be some problem with fouling of open bearings in some waters which might indicate a sealed bearing instead, and which might not have been anticipated by someone designing the thing in another country, but on the other hand I know dozens of people in Florida who have used the old Bruntons now for going on two decades with no maintenance at all and no problems. That includes my own old boat, which had the old water-lubricated type installed in the 90's, and is still going strong some 20,000 hours later.

In the absence of real statistics, we all have to make our judgments on the basis of whatever anecdotal data we can find, which of course is not very precise at all, and not for any of us. The information I possess indicates -- does not prove, but leads me to believe -- that aside from a specific run of props with bad locking washers, which were subject to a factory recall, Brunton props are just as reliable as any other prop which has moving parts. Other anecdotal information leads me to believe that Brunton has poor customer service, which I think is somewhat understandable since they are an engineering company set up to deal with professional engineers building and maintaining big ships, where every prop is a major custom project in itself. Not with the general public. Which of course is no comfort to a member of the general public with a problem, and this has certainly hurt Brunton's reputation. Everyone will have to make up his own mind based on the information he can dig up. I for one have been using them for 20 years with great results and no problems. As always, YMMV
__________________
Dockhead is online now   Reply With Quote
Old 15-04-2013, 21:39   #412
Registered User

Join Date: Feb 2012
Posts: 2,441
Re: Autoprop ?

Quote:
Originally Posted by Dockhead View Post
Hundestedt props are fantastic, but few of us have boats big enough to use them. The smallest is for 150 horsepower; I've only got 100.
Other brands are available, eg Sabb, which go down to about 60 Hp (although I believe they no longer provide a gearbox which is suitable for sailling craft: ie full feathering as well as full pitch control). The available offerings do in recent decades seem to have progressively largely quit the small-engine sizes, but there are plenty out there on existing craft.

My point was that, contrary to what you posted, self-pitching props are not the only solution providing the benefits you described.
__________________
Andrew Troup is offline   Reply With Quote
Old 16-04-2013, 12:58   #413
Moderator
 
Dockhead's Avatar

Cruisers Forum Supporter

Join Date: Mar 2009
Location: Cowes (Winter), Baltic (Summer) (the boat!); somewhere in the air (me!)
Boat: Cutter-Rigged Moody 54
Posts: 19,737
Re: Autoprop ?

Quote:
Originally Posted by Andrew Troup View Post
Other brands are available, eg Sabb, which go down to about 60 Hp (although I believe they no longer provide a gearbox which is suitable for sailling craft: ie full feathering as well as full pitch control). The available offerings do in recent decades seem to have progressively largely quit the small-engine sizes, but there are plenty out there on existing craft.

My point was that, contrary to what you posted, self-pitching props are not the only solution providing the benefits you described.
I have always admired the lovely Hundested props. Have you ever seen one? The are works of art. But inapplicable to a non-superyacht sized sailboat.

I am not aware of any feathering, variable-pitch (self-pitching or manual) prop available for sailboats other than the Brunton, other than the quite new (and very interesting-sounding Ecowind from Maxprop), so I can't agree with your point. Woukd that it were not so - this is such an extraordinarily useful property in a prop. If there is a variable pitch, feathering prop available other than these two, I would love to hear about it.

I would also love to hear how the new Ecowind is working out for CFers who have installed it. The Autoprop is ingenious but 30-year old technology; presumably the very good Maxprop people should have had found some opportunities to come up with some improvements. The droopy blade of the Autoprop is a real disadvantage; presumably the geared Ecowind doesn't suffer? Might well be worth the added complexity of gearing the blades.
__________________
Dockhead is online now   Reply With Quote
Old 16-04-2013, 13:20   #414
Marine Service Provider
 
fstbttms's Avatar

Cruisers Forum Supporter

Join Date: Oct 2006
Location: Under a boat, in a marina, in the San Francisco Bay
Posts: 3,592
Re: Autoprop ?

I spoke with Fred Hutchinson of PYI at the Strictly Sail show last week and he told me that they're no longer selling the Ecowind prop into every application. Apparently they've decided it has somewhat limited use in the pleasure boat market.
__________________
fstbttms is offline   Reply With Quote
Old 16-04-2013, 14:08   #415
Moderator
 
Dockhead's Avatar

Cruisers Forum Supporter

Join Date: Mar 2009
Location: Cowes (Winter), Baltic (Summer) (the boat!); somewhere in the air (me!)
Boat: Cutter-Rigged Moody 54
Posts: 19,737
Re: Autoprop ?

Quote:
Originally Posted by fstbttms View Post
I spoke with Fred Hutchinson of PYI at the Strictly Sail show last week and he told me that they're no longer selling the Ecowind prop into every application. Apparently they've decided it has somewhat limited use in the pleasure boat market.
That's really too bad!

I guess it must not work as well as it was supposed to. I hope they will keep working on it.
__________________
Dockhead is online now   Reply With Quote
Old 16-04-2013, 14:19   #416
Marine Service Provider
 
Scott Berg's Avatar

Join Date: Jul 2011
Location: Aboard
Boat: Seaton 60' Ketch
Posts: 958
I have a Hundested FP on CHARDONNAY
Driven by a Lehman 135 and a big V drive with 3+/1 reduction--love it

Glad to discuss the merits and issues
Perhaps a CP Prop thread?
Scott
__________________
Scott Berg
WAØLSS
SV CHARDONNAY
Scott Berg is offline   Reply With Quote
Old 16-04-2013, 15:35   #417
Moderator
 
Dockhead's Avatar

Cruisers Forum Supporter

Join Date: Mar 2009
Location: Cowes (Winter), Baltic (Summer) (the boat!); somewhere in the air (me!)
Boat: Cutter-Rigged Moody 54
Posts: 19,737
Re: Autoprop ?

Quote:
Originally Posted by Scott Berg View Post
I have a Hundested FP on CHARDONNAY
Driven by a Lehman 135 and a big V drive with 3+/1 reduction--love it

Glad to discuss the merits and issues
Perhaps a CP Prop thread?
Scott
Please, more prop porn

For those who have drooled over Hundested props. Any lewd photos?
__________________
Dockhead is online now   Reply With Quote
Old 28-07-2013, 14:53   #418
Registered User

Join Date: Apr 2012
Location: Portsmouth (UK)
Boat: Bavaria
Posts: 14
Images: 1
Re: Autoprop ?

Autoprop update. Since my last post we have had the worst sailing spring in memory. Our boat sat idle in the marina for 2 months, we got out at easter for a couple of days but the weather was so bad we tied up and went home to light the fire and dry out clothing. We have just finished a 3 week boating holiday westward along the south cost of England down to lands end and back is fantastic weather.
I am sitting in Lymington, as always on returning to the solent the weather has changed F6-7, lightning, squals and over-priced marinas:-(
The Brunton prop has real been a bonous, adding that little extra umph to a sail when needed. No issues or problem since my last post. We recorded 7.75kn boat speed(SOG) and 10.72kn (COG) crossing lyme bay yesterday. We left Torquay at 05:30 Hrs and were tied up in Lymington by 17:40.
Since my last post I have machined (on my lathe) a plate that will allow me to change the annode to one I have made a casting for, that is bigger and fits with an M12 thread rather than the small M6 fixings. This should make the annode last longer.
Again I have to say I am happy with my Auto prop so far; with another 4500 miles on my log since I fitted it, some sailed, some motor sailed and some sailed. I guess its paid for itsself now.
Happy, safe sailing!
Blinky
__________________
Blinky is offline   Reply With Quote
Old 03-01-2015, 10:38   #419
Registered User

Join Date: Apr 2012
Location: Portsmouth (UK)
Boat: Bavaria
Posts: 14
Images: 1
Re: Autoprop ?

Well a final update. I have just sold my Bavaria 32 and ordered a new boat to arrive in March 2015. The Autoprop has been serviced each year and the anode mod made a big difference to the anode life. its paid for its self a couple of times over. I have ordered the new boat with the factory fitted standard 2 blade prop. I will be fitting a new 3 blade Autoprop in the summer along with a 3 blade rope cutter from Ambassador marine (Ambassador Marine - Home of the Stripper Propeller Protector).
I have decided to invest in "Copper-coat" from new and then upgrade the prop when I have more time and the lift out price is better :-)
Happy sailing.
Blinky.
__________________
Blinky is offline   Reply With Quote
Old 19-01-2015, 17:49   #420
Registered User
 
Benronpro's Avatar

Join Date: May 2011
Location: S/W Australia
Boat: Oyster 435
Posts: 18
Re: Autoprop ?

Gordon from Athene of lymington, It's been a couple of years now since you have changed out your Max-prop to an Autoprop. So I (and no doubt other readers) would be very interested to hear about your opinions of the Autoprop as time goes on. As for ourselves with a similar Oyster 435 we have continued on with our aged max-prop but observation has shown plenty of wear in the hub and cones which is revealed as play in the blades( I guess to be expected after 20 plus years of service) however it has proved very reliable thus far. Now the time has come to replace the prop. So your view of suitability and correct sizing for the 435 would be much appreciated. Incidentally looking in to the left hand turn of our prop, the max prop can be set up to turn right or left and apparently the MS4 gearbox selector can be reversed to safely run the gearbox in either direction at full power loading ( can anyone clarify this?). I believe this set up may help counter act prop walk due to the prop shaft exiting the hull at an angle slightly to the portside ( to clear the rudder skeg) .
Anyway this has been a very informative albeit drawn out thread and any updated info on Bruntons Autoprops would be much appreciated by all no doubt.
Cheers Ben..
__________________

__________________
Benronpro is offline   Reply With Quote
Reply

Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
For Sale: Autoprop Propeller wunscot Classifieds Archive 7 16-01-2010 13:16
Autoprop - Used Value Conch Cruzer Monohull Sailboats 4 30-07-2009 18:11
Used Autoprop For Sale Conch Cruzer Classifieds Archive 0 27-05-2009 05:15
H5 AutoProp Hub markpj23 Classifieds Archive 0 08-03-2009 13:45



Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 04:10.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.