Brunton Autoprop

[ShaunG]

fo it the easy way

polished mine this year, wet and dry upto 1500 grit (on a DA Sander) then i used this from screwfix

http://www.screwfix.com/prods/75331/Abrasives/Polishing/Metal-Polishing/Metal-Polishing-Kit-100mm

used on a drill and highly polished in 1 hour, easily see your face and have a shave in it. Well worth the cost and now looks fantastic

 

[Sailfree]

Look up metal polishers equipment suppliers on google. I found a very helpful firm based in Salisbury.

They sold me 2 large discs & mandrill for a 9" angle grinder (polishers are too slow). These are about 12 thick and sewn together pieces of cloth (i think the coarser one is sisal (Spelling!). Also bought a green brick of abrasive.

Apply edge of disc to abrasive brick and the spinning melts the brick onto the outside 1" edge then apply to prop. Soon polishes metal to bright shine and no hard work. Green abrasive dust everywhere though.

This is the way professional metal finishers would do it.

Big powerful 9" angle grinders are not that expensive if you can get to Makro warehouse.

Trust this helps

PS ended up buying lots of wet & dry of various grades (packs of 25) from the same supplier as they were so cheap.

 

[Blinky]

My Autoprop end anode has had the stainless bolts replaced by nylon ones. This also helps with the bolt hole corrosion issue, although it still occurs. Available on ebay.

I had the same issues with the anode, @£36 a go + the liftout anode replacement is a a problem. covering the bolt and holes with Sikaflex or paint helps. However ther is another solution if you are handy with a lathe.
Hope you can see how this works.

Blinky

 

[Daydream believer]

Do not bother with all that sanding
I have a commercial brick cleaner called Disclean which I have left over for years. I brush this on & it fizzes & it takes 15-20 minutes to get a clean but dull finish. These days you can buy a 5 litre can of patio cleaner from Travis Perkins which will last years . It is less powerful bit still does the job
Brunton suggest one should NOT apply antifoul to a prop. When a chip comes in the antifoulling this section of the prop starts to erode. If the whole prop is exposed any wear is more even rather than an isolated spot

Re performance of Brunton against the original fixed volvo prop
Fuel consumption greater ( up from 1.66 litres per hour to 2.0 or more
Max revs down from 3500 to 2800
Max economical speed down to 5.9 knts from 6.2 but note that is now 2 litres instead of 1.66
Prop wash more pronounced
Changing from reverse to forward causes the boat to rotate 180 degrees before the prop bites.
Manouvering poorer
Vibration marginally more but not unacceptable
Anodes now have to change shaft & end anode every year instead of every 3 years
Drag reduced by about .5 knts at 6 knts
Performance when motor sailing absolutely brilliant. Bearing in mind I seem to do a lot of this the prop is sort of worth having but would probably not have another unless it was a 3 blade in lieu of the 2 blade
When in chop one has to motor flat out thus using more fuel. What happens is that when the boat hits a wave it wants to stop. The prop then has no forward motion so feathers to a low pitch. The oat then does not advance immediately until the prop starts to re pitch itself. Then the boat starts to go forward bit hits the next wave & stops again
Brunton changed the first prop as max speed in 1 metre chop at max revs was 2 kts. Situation improved but now fuel consumption has gone up & max revs lower because the pitch has been increased. The prop is self pitching bit relies on an initial pitch set in the blades

 

[johnphilip]

Brilliant or Too much spare time?

Like this you mean?

Hard work first year, easier every time thereafter. Start with 300 wet/dry used very wet, then 600 very wet, then 1000, very wet. Then several polishes with Brasso with a final one just before launch as this takes off any last minute tarnish. Next lift out, try to clean whilst still wet as it is easy to push off the slime with a soft piece of plastic, then re-polish.

You missed a bit of the shaft the other side of the Cutless.

Sour Grapes

 

[davidwf]

I polished up my Autoprop last June, although no where near as good as the examples on this thread.

I then applied the clearcoat antifouling that is on trial, boat is not coming out until June so I will be very interested to see how that's done.

Also use the paint trick to stop the anode falling off and recently Bruntons have supplied the anode with plastic screws.

 

[dilly]

my prop

my prop after 12 mounths in millford marina