Corroded propeller

[jeztee]

After 4 years use my Bavaria 30 propeller has corrode beyond repair. On the volvo d120 sail drive leg there has always been a sacrificial anode but aim not sure if that was for the drive leg or the prop. can any one advice me if there should be a separate anode for the prop. Thanks for reading this.

 

[vyv_cox]

It depends on the make of the propeller, I believe. Volvo's own folding propellers are electrically isolated from the shaft and have their own anode. Other makes do not and rely on the saildrive anode.

 

[VicS]

The 120 sail drive has a ring anode to protect the drive leg. It is important that it is inspected regularly and replaced in good time.

As Vyv says Volvo folding props also have two small anodes to protect the prop. They should also be inspected regularly and replaced when necessary The life of these relatively small prop anodes can be very short... 6 months, maybe less sometimes .

Other makes of folding prop may also have their own anodes.

The engine owners manual should contain the details relating to the saildrive and the original Volvo prop.

Do you leave the boat plugged into shorepower supply for prolonged periods. If so is it fitted with a galvanic isolator

 

[Sailfree]

It depends on the make of the propeller, I believe. Volvo's own folding propellers are electrically isolated from the shaft and have their own anode. Other makes do not and rely on the saildrive anode.

There are but the one I had in 1999 the anodes only lasted 6 months or so on a charter boat and flew off. Volvo replaced the prop under warantee once then gave me my money back the 2nd time.

I believe the latest Volvo folding props are better but personally would not touch them with a bargepole!!

 

[Tranona]

The standard aluminium fixed prop is in theory isolated from the drive unit by a rubber bush. You can, however get corrosion in the aluminium if the coting is damaged. The bush can also become detached from the hub casting. As others have said, many folding or feathering props have their own anodes and some of these can erode very quickly, and then the prop and mechanism can corrode. The drive itself is protected by the ring anode.

 

[savageseadog]

Propellers are usually electrically isolated on sail drives. Many earlier and current sail drive propellers don't have anodes. Speaking from experience they do corrode despite supplier protestations. I'm not sure of the mechanism but might be stray current rather corrosion rather than electrolysis. I've dissolved two folding Gori's so speak from experience and can recommend a Kiwiprop as an alternative.

 

[bobgarrett]

A friend of ours had big problems with anodes eroding then props and saildrives etc. in a new yacht. All sort of things were blamed like sailing near big ships. It turned out to be a wiring fault from, I think the calorifier, so that whenever it was switched on there was stray current which found its way through to the engine and out.