Brunton Autoprop -- Brinelled Bearings

[unclemack]

Originally Posted by Frankly

As to why Bruntons used ball bearings, those blades have to all assume the same precise angle of attack. Get a little weed in one of the bearing races (probably not likely on the sealed unit) and you will be off to the dentist to get your fillings replaced.

Agreed, but -

Brinelling (or false-) must be capable of introducing resistance to rotation when present mustn't it?

Given that roughness can be felt on inspection?

Once it starts the increased "hammering" in a ball or roller bearing can rapidly lead to failure.

[Harryws]

Brunton Autoprop
Has any vessel you know of lost a blade from a Brunton Autoprop propeller.
I have one fitted to my 42 ft Adams cruising yacht and three years ago one of the three blade dropped off. It was because the securing nut came loose and disappeared along with the blade. I returned the prop to Bruntons to have them install a new blade and balance the propeller. They did this at some cost.
Recently another blade has dropped off. I have again returned the Autoprop to Bruntons UK. What should I do? Has anyone had a similar experience?

[Dockhead]

Originally Posted by Harryws

Brunton Autoprop
Has any vessel you know of lost a blade from a Brunton Autoprop propeller.
I have one fitted to my 42 ft Adams cruising yacht and three years ago one of the three blade dropped off. It was because the securing nut came loose and disappeared along with the blade. I returned the prop to Bruntons to have them install a new blade and balance the propeller. They did this at some cost.
Recently another blade has dropped off. I have again returned the Autoprop to Bruntons UK. What should I do? Has anyone had a similar experience?

It's a known issue with the early water lubricated bearing models.


Bruntons should have done a recall on those, but apparently didn't. I think it takes some nerve, frankly, to be taking big money from people to solve what is clearly a design defect.


I believe you can retrofit the tab lock washers which the later models have, which apparently stop the problem.


I would demand that Bruntons do this one at their expense. They should have upgraded the washers or at least offered to do so. I doubt they will step up, but I would still make a stink about it, if I were you.

[Harryws]

This Autoprop lost a blade in 2015 and was returned to Bruntons for them to fit a new blade and to balance the prop. They had ample opportunity to withdraw it or to make any modifications. They returned it and it only did about 2000 nm before the second blade fell off.
We are still in the early stages of negotiations however Australian law is very explisit about selling a product which has to be "Fit for purpose" ie work.
Clearly loosing two blades from the same propeller within in a short time raises questions.
I wait for their response.

[Dockhead]

Originally Posted by Harryws

This Autoprop lost a blade in 2015 and was returned to Bruntons for them to fit a new blade and to balance the prop. They had ample opportunity to withdraw it or to make any modifications. They returned it and it only did about 2000 nm before the second blade fell off.
We are still in the early stages of negotiations however Australian law is very explisit about selling a product which has to be "Fit for purpose" ie work.
Clearly loosing two blades from the same propeller within in a short time raises questions.
I wait for their response.

Well, press them. They shouldn't get away with this. I think losing any blade at all, much less TWO blades, is totally unacceptable, and they should stand up and at the very least pay for the second one.



I believe that there was even a recall for this issue -- maybe someone knows exactly.

[Harryws]

Today Nov 2021 I have been contacted by a yacht owner who last week lost a blade from their almost new Autoprop here in Australia. This is the fifth blade to drop off a Autoprop supplied to Australian vessels.
I had two blades (different ones) fall off within three years and on both occasions sent the prop back to the Manufacturer Bruntons in the UK. On the last occasion they refused to do anything and until they received a lawyers letter would not return my still broken prop to me. The eventually bundled it up and freighted in a cardboard box in pieces with a number of missing parts.
My insurance would not cover my vessel with an Autoprop fitted in case a blade came off and holed the boat.
This is a situation that every vessel who has a Autoprop attached should appreciate and remove theirs immediately

[Moonshine36]

SO, I too have a Brunton Autoprop, on a Mason 44.
As a monthly routine, I start the engine and run her up to temperature, shifting from forward to reverse several times, just to give her some "exercise" and the discourage any marine growth that minght think of attaching itself. Today, I noticed considerable vibration coming from the Brunton Autoprop, I believe.
I have winter cruising planed soon, so am considering pulling the boat to investigate the vibration. and addressing the issue if I can.

QUESTION: Does it take any special tools to pull the Brunton Autoprop off the prop shaft ?

I have a traditional fixed 3 blade prop that I can mount if the AP is an issue.
Ken

[Frankly]

Typically use the three zinc holes to attach a special puller to the prop (don't try the nylon screws). I made mine from a round disk of 1/2" steel. Bruntons did sell one but kind of pricy IMO. Depending on clearances and taper grab might get it off with hardwood block and hammer.

I pull mine off all the time to repaint with the boat in the water (but I live on the opposite corner of the country).


Frankly

[fstbttms]

Gee, I thought Brunton’s redesigned Autoprop to remedy the blade loss issue years ago. Bwhahahaha!

[Frankly]

The AP I have is the old open water bearing lubricated model. There is a bolt with a special wedge shaped shaft that locks everything in place. Bruntons specs a pretty good torque value on the nut to pull that wedge section into the main locking cap. Mine is 25 years old, one trip back to Bruntons for race remachining and several bearing replacements but I am a happy owner. The PO was the one to write that "thin your wallet" check for the original purchase.


Frankly