Bronze Outside Cutlass Bearing in Aluminium Boat Corrosion?

[surfmachine]

Hi! Bought a new cutlass bearing for my aluminium hulled yacht. But it had a bronze outer sleeve where it fits into the propellor tube. So direct contact between aluminium hull and bronze outer sleeve of cutlass bearing. Will this result in bad corrosion as they are dissimiliar metals?
The original bearing had a plastic/fibre outer sleeve. Salesman told me the brass ones were better!
Any suggestions please?
Cheets from Keith.

[HappyMdRSailor]

I'm not the galvanic corrosion expert... Or even a plebe regarding aluminum hulls... BUT...

If your previous composite shell cutlass bearing gave satisfactory service... Why would you change things???

They still make them... (composite)

[GordMay]

Originally Posted by HappyMdRSailor

I'm not the galvanic corrosion expert... Or even a plebe regarding aluminum hulls... BUT...
If your previous composite shell cutlass bearing gave satisfactory service... Why would you change things???
They still make them... (composite)

Indeed.
➥ Johnson Cutless Non-Metallic Bearings - Shaft Diameters 1-3/8" thru 2-1/8" - Shaft Bearings & Glands - Engine Systems - Downwind Marine

[HappyMdRSailor]

Originally Posted by GordMay

Indeed.
➥ Johnson Cutless Non-Metallic Bearings - Shaft Diameters 1-3/8" thru 2-1/8" - Shaft Bearings & Glands - Engine Systems - Downwind Marine

See... At first I was going to post a link... Then I thought...

Nahhhh....

Gordo's here ... He's posting an awful lot of (really good) humor lately....
Maybe he's bored???

[surfmachine]

Well fellas. Thanks for the replies. Shop did not have the composite bearings so like a fool i bought the brass one! Now hauled out in krabi boat lagoon. 110 miles from marine stores and i fly back to audsie tomorra. So i will buy a composite bearing in west australia to fit when i return in april 2015.
Short answer appears to be dont use em in alloy boats.
Fair winds from Keith.

[HappyMdRSailor]

Originally Posted by surfmachine

Well fellas. Thanks for the replies. Shop did not have the composite bearings so like a fool i bought the brass one! Now hauled out in krabi boat lagoon. 110 miles from marine stores and i fly back to audsie tomorra. So i will buy a composite bearing in west australia to fit when i return in april 2015.
Short answer appears to be dont use em in alloy boats.
Fair winds from Keith.

Keith... I don't think either of us has any experience with the bronze cutlass/aluminum hull... We're simply saying "why would you"?

Well... your predicament explains EXACTLY why you would switch... For the short term... I have a feeling that there's a 99.9% chance of NO PROBLEMS...

But.. as mentioned... No personal experience... There's a few Aluminum hull gurus here... do some digging ... Most of all... Fair Winds...

[jannw]

Absolutely 100% don't use a bronze tubed cutlass bearing in an alloy boat!

Use plastic.

If you can't find one pre-fabed in the right size a fitter and turner can machine a plastic sleeve up on a lathe into which you slip the internal bearing material.

[surfmachine]

Ok. Bloody thais will sell you anything for a quick bhat!!!
Keith.....

[skipmac]

Originally Posted by jannw

Absolutely 100% don't use a bronze tubed cutlass bearing in an alloy boat!

Use plastic.

If you can't find one pre-fabed in the right size a fitter and turner can machine a plastic sleeve up on a lathe into which you slip the internal bearing material.

Copper or copper alloys (like bronze or brass) are huge nonos for Aluminum. Very incompatible and the loser will be the Aluminum. If you can't even use copper based bottom paint on an aluminum boat then why consider using copper alloy parts.

Good example of what could happen. Nigel Calder posted a photo in his maintenance book of an aluminum tank where a copper penny had fallen from someone's pocket onto the top of the tank. Left a nice, round hole through the top of the tank.

[Cadence]

Hook a wire to each and don't worry about solar power. The bearing probably only has limited exposure to the water and is probably in direct contact with the aluminum for the most part and probably isn't a major problem. I think I would eliminate the chance of any problem.

[EngNate]

Would NOT be a good idea to use the bronze. You will end up with the bore oversized from corrosion and thus a serious issue to deal with.

[shipleft]

Everyone that buys or builds an aluminum boat should have this tattooed across their forehead in inverted script so you can re-read it every morning in the mirror," DO NOT USE ANY COPPER ALLOYED MATERIALS ANYWHERE ON THIS BOAT". They are aluminum boat killers! Especially if used below the waterline in salt-water. That composite shell cutlass was put there for a reason, the fitting it goes into would not be there by now if the last person to change or install that bearing had used the bronze or brass version.No if's, and's, or but's.