AutoProp - This Is a Shame !

[markpj23]

Unfortunately the previous owners have obviously let these props fall into a state of serious neglect. My only hope is that (thanks to this forum) I've learned that the factory recall applies to my serial numbers. I may get lucky and have at least part of the repairs needed covered by the recall.

So - as the surveyor and I inspected these, we saw that on all 6 blades (both props) there were ball bearings missing. On 2 blades we could feel flat spots in the bearings as we rotated the blade. Little did I know at the time the the seals which hold the bearings in place were completely gone on all blades. We should NOT be able to see the ball bearings at all!!

And on the Port prop, we noticed this large gap between the hub and the sail drive:


We tried to tighten the nut but that had no effect. We never did understand what was causing this issue. With the prop nut on tight we could still slide the prop back and forth a good 1/2 to 1 inch! Also the locking allen head cap screw is long gone, so we put loctite on the nut to reduce the worry for the return trip.

Oh and forget the zincs on the end cones - both were long gone. The sail drive zincs are 70 - 80% wasted also.

In this picture you can see how pink the entire assembly is. Electrolysis has eaten the leading edge of 2 blades to were there's a 1 inch long by 1/4 inch deep chunk missing. Note the obvious gap between the blade and the hub - there should be a seal in there. What a mess!



There should be a penalty for letting things get this far out of hand. Unfortunately I'm the one paying the penalty in this case....

After doing some research I've just about decided to forget the AutoProps altogether and go a different route.

[Charlie]

Its a shame that the people let those expensive props go like that. Are/Were you able to negotiate a reduction in price?

[Badsanta]

Did the surveyor notice this, Before you bought it?

[markpj23]

Yes we noticed all of this during the survey haul-out. In fact that's the surveyor wearing the blue gloves with his finger between the prop hub and the sail drive zinc.

I've contacted the folks at AB Marine (so far good support via telephone) and have determined that the STBD pop can be fixed with an overhaul kit to replace inner & outer bearings. The port one I'm afraid will likely either need replacement or at least 2-blade replacement and subsequent re-balancing at the factory (yes in the UK).

So about $5K if I go that route. I'm also looking at other prop options.

[philip van praag]

Originally Posted by markpj23

Yes we noticed all of this during the survey haul-out. In fact that's the surveyor wearing the blue gloves with his finger between the prop hub and the sail drive zinc.

I've contacted the folks at AB Marine (so far good support via telephone) and have determined that the STBD pop can be fixed with an overhaul kit to replace inner & outer bearings. The port one I'm afraid will likely either need replacement or at least 2-blade replacement and subsequent re-balancing at the factory (yes in the UK).

So about $5K if I go that route. I'm also looking at other prop options.

your price is verry high i have these props and they cost £1.5k new in uk at curent rates you should be under $3k
if you have had no experance of these props they are worth the efort.
also be awear as a large bronze prop they go through anods verry quick
i use 2 sets a year!
also spoke to them at recent boat show">london boat show.
found out that if you paint the area were the anodes bolt on they last longer as this is normaly the area that erods first and they drop of befor half the anode is worn.
mentioned this seem a bit of that we should have to deal with a small design falt like this and that they should put a plate in the anode to help keep it in place longer tets see what hapens.
good luck with your repairs.

[markpj23]

Thanks Phillip. I'll look for other resellers than AB Marine, but I think they have an exclusive sales arrangement.

[markpj23]

Well now I know the rest of the story....

The STBD prop refused to come off the shaft. A few hours and 1/2 a tank of Acetylene later we had the hub rubber left on the shaft...



And the prop has seen better days. Very rough as I turn the blades.... So I'm pretty sure that what I found on the Port pop will be true here also.



Here's where things get pricey...

I had hoped to get by with rebuilding the props. Got the rebuild kits and started at the Port prop tonight. What I found leaves no hope... check out the bearing race here and imagine what it must sound like as the blade rotates... On the bright side - I wouldn't have to worry about a submarine surfacing underneath me since they'd hear me coming a week in advance .



I have 2 of 3 blades in this condition - meaning that for the cost of refurbishing 2 blades I can replace the whole unit. If of course I want to spend that kind of $$ just to have this problem again in the future.

To be fair, the 2 blades with the ruined bearing race have a nick on the end of the blade as if they were run aground. The blades are not bent - just nicked, however, and I would hope that a 'soft' grounding would not cause this sort of damage. I do not know the whole history of course so this is just speculation on my part.

What is fact, of course, is that for the price of replacing a single Autoprop I can buy a pair of Flex-O-Fold units. Wanna guess which path I choose?

[Silver Cloud]

I have an Autoprop on my Catalina 42. AB Marine had rebuilt the prop in 2007. In May of 2009 and 225 hours later a blade came off. Buntons Marine replaced the blade for $1500. I had it lubricated every six months. I am always in deep water. It never touched anything but saltwater. I only go to Catalina and back. Other than the lost blade there was not any evidence of damage or distress.

At the time Steve Armitage of AB Marine told me that losing a blade was a “rare occurrence” and that he did not have an explanation for why the blade fell off. David Sheppard of Brunton's Propellers Ltd, told me losing a blade is an “an exceptional case”. Contrary to their comments the prop has been subject to a recall for lost blades. If you search other support groups and blogs you will find many others that have lost Autoprop blades. It demeans their credibility to say otherwise.

Although I enjoy the performance of my Autoprop my experience with AB Marine and Brunton's Propellers has been extremely disappointing. They are unwilling to stand behind their expensive product. In all their replies I feel like I am hearing from a politician trying to avoid giving a straight answer.

[Dockhead]

Originally Posted by philip van praag

also spoke to them at recent london boat show.
found out that if you paint the area were the anodes bolt on they last longer as this is normaly the area that erods first and they drop of befor half the anode is worn.
mentioned this seem a bit of that we should have to deal with a small design falt like this and that they should put a plate in the anode to help keep it in place longer tets see what hapens.
good luck with your repairs.

+1

The anode design on the Brunton Autoprops is awful -- they fall off in a couple of months if you don't paint the screw holes with antifoul.

You can get an adapter to use a regular conical prop anode:

Autoprop Adaptor page

Might be worth thinking about.

[capn_billl]

Originally Posted by markpj23

Well now I know the rest of the story....

The STBD prop refused to come off the shaft. A few hours and 1/2 a tank of Acetylene later we had the hub rubber left on the shaft...



And the prop has seen better days. Very rough as I turn the blades.... So I'm pretty sure that what I found on the Port pop will be true here also.



Here's where things get pricey...

I had hoped to get by with rebuilding the props. Got the rebuild kits and started at the Port prop tonight. What I found leaves no hope... check out the bearing race here and imagine what it must sound like as the blade rotates... On the bright side - I wouldn't have to worry about a submarine surfacing underneath me since they'd hear me coming a week in advance .



I have 2 of 3 blades in this condition - meaning that for the cost of refurbishing 2 blades I can replace the whole unit. If of course I want to spend that kind of $$ just to have this problem again in the future.

To be fair, the 2 blades with the ruined bearing race have a nick on the end of the blade as if they were run aground. The blades are not bent - just nicked, however, and I would hope that a 'soft' grounding would not cause this sort of damage. I do not know the whole history of course so this is just speculation on my part.

What is fact, of course, is that for the price of replacing a single Autoprop I can buy a pair of Flex-O-Fold units. Wanna guess which path I choose?

Actually a nick can be caused by a couple of things. soft-grounding, yes there may be an oyster shell or rock in the mud. Lobster trap - yes, they sometimes have heavy metal parts. Floating debris - yes, a board with nails? I dinged one with a steel rod, (dock support rod had broken and was protruding into the slip. A hard grounding will usually bend the blades.

[b36]

Originally Posted by Dockhead

+1

The anode design on the Brunton Autoprops is awful -- they fall off in a couple of months if you don't paint the screw holes with antifoul.

You can get an adapter to use a regular conical prop anode:

Autoprop Adaptor page

Might be worth thinking about.

Hi, I have an Autoprop on my Bavaria 36 and very happy about the efficiency while motoring or motor sailing. It is 2 years old now so hope I will not get into some trouble later on but so far so good....

I was very disappointed with the first anode nealry falling off, about three months after prop installation (as you know due to the quick consumption of thin anode sections around the holding screws) as I lifted the boat again for hull cleaning.

I now can say that thanks to the manager of the yard where I do maintenance a very good solution was found. He covered each screw head and area of anode around screw - all around the thin sections - with white Sika, he calls it a "Sika plug". To my surprise the Sika plugs were still there after more than 18 months when I lifted again the boat. Anode still in place (nearly all consumed apart from around the screws!).

This has been for me the major concern with the Autoprop but not any more.

[b36]

Originally Posted by b36

Hi, I have an Autoprop on my Bavaria 36 and very happy about the efficiency while motoring or motor sailing. It is 2 years old now so hope I will not get into some trouble later on but so far so good....

I was very disappointed with the first anode nealry falling off, about three months after prop installation (as you know due to the quick consumption of thin anode sections around the holding screws) as I lifted the boat again for hull cleaning.

I now can say that thanks to the manager of the yard where I do maintenance a very good solution was found. He covered each screw head and area of anode around screw - all around the thin sections - with white Sika, he calls it a "Sika plug". To my surprise the Sika plugs were still there after more than 18 months when I lifted again the boat. Anode still in place (nearly all consumed apart from around the screws!).

This has been for me the major concern with the Autoprop but not any more.

The boat maintenance works just completed, this is the autoprop with the Sika plugged screw heads.

[Valkyrie654]

I agree the standard zinc design is great for selling zincs, not so good for protecting your expensive prop. The best solution is to have a short stub machined out of bronze with a flange on it where the bolt pattern on the flange matches the three bolt pattern on the prop, and the stub is the same diameter as the prop shaft. Then put a standard shaft zinc on it. No need to carry special prop zincs like some of the other adaptors on the market force you to do. An added bonus is that a shaft zinc is the cheapest zinc you can buy. Reducing the numbers of spares on board is always a good thing when one spare can cover multiple applications. Our little stub adaptor cost us $35 to have machined in Mexico a couple of years ago.

[Dockhead]

Originally Posted by b36

Hi, I have an Autoprop on my Bavaria 36 and very happy about the efficiency while motoring or motor sailing. It is 2 years old now so hope I will not get into some trouble later on but so far so good....

I was very disappointed with the first anode nealry falling off, about three months after prop installation (as you know due to the quick consumption of thin anode sections around the holding screws) as I lifted the boat again for hull cleaning.

I now can say that thanks to the manager of the yard where I do maintenance a very good solution was found. He covered each screw head and area of anode around screw - all around the thin sections - with white Sika, he calls it a "Sika plug". To my surprise the Sika plugs were still there after more than 18 months when I lifted again the boat. Anode still in place (nearly all consumed apart from around the screws!).

This has been for me the major concern with the Autoprop but not any more.

I agree with you - the anode is really poorly engineered. I'm guessing might be an area where the shape of the anode is important for hydrodynamics of the prop, so maybe they were thinking more about that than about the loss of structural integrity as the anode wears. The could have at least put steel inserts in these expensive anodes as we see even on plenty of cheap shaft anodes.

I have been pitting a dab of anti foul or prop speed on the thin bits around the outside of the screw holes; works pretty well. Also, I don't go more than 4 months between lifts -- and I don't recommend that you let your anodes get worn "almost all the way down" - their performance already starts to seriously degrade at 50%. Anodes are pretty cheap compared to replacing a prop.

[b36]

Originally Posted by Dockhead

I agree with you - the anode is really poorly engineered. I'm guessing might be an area where the shape of the anode is important for hydrodynamics of the prop, so maybe they were thinking more about that than about the loss of structural integrity as the anode wears. The could have at least put steel inserts in these expensive anodes as we see even on plenty of cheap shaft anodes.

I have been pitting a dab of anti foul or prop speed on the thin bits around the outside of the screw holes; works pretty well. Also, I don't go more than 4 months between lifts -- and I don't recommend that you let your anodes get worn "almost all the way down" - their performance already starts to seriously degrade at 50%. Anodes are pretty cheap compared to replacing a prop.

Hi, I was not very clear there but "after 18 months almost all consumed" referred to the tip of the anode which is no more than 30% of its mass (anode also protrudes in the hollow of the prop body), considering 18 months above the average time between lifts, this works fine for me.