Rapid Disintegration of Saildrive Leg

[RaymondR]

Cheap battery charger with autotransformer perhaps?

[fstbttms]

Follow up inspection of saildrives:

https://youtu.be/huTcj0NboNM

[Sailmonkey]

Originally Posted by fstbttms

Follow up inspection of saildrives:

Was anything done to the boats wiring? What was found to be the cause of the drive being dissolved?

[Knot Safety]

Naive question - but why wouldn’t the anode have stopped the corrosion in the first video? There seemed to be lots of anode left and that is the purpose of it being there - to stop corrosion.

[Thumbs Up]

Originally Posted by Bill O

Wow that is pretty bad.

Did a little research before and although Volvo and Yanmar use the same saildrives it seems The Yanmar SDs are more prone to severe corrosion than the Volvo. No explanation was given for this observation.


Bill O.

Volvo saildrives are electronically isolated from the engine, Yanmar saildrives are connected.

[Sailmonkey]

Originally Posted by Knot Safety

Naive question - but why wouldn’t the anode have stopped the corrosion in the first video? There seemed to be lots of anode left and that is the purpose of it being there - to stop corrosion.

Anodes are not there to protect against stray current corrosion, only to protect against the currents created by dissimilar metals in an electrolyte.

[capn_billl]

Originally Posted by Sailmonkey

Anodes are not there to protect against stray current corrosion, only to protect against the currents created by dissimilar metals in an electrolyte.

The anode acts like a very tiny battery to counteract small currents, and voltages.

At best it can overcome a 0.3 volt ( iron to zinc) potential.

The 12 volts from the battery is going right over it.

[ggray]

So the follow-up inspection was what, 7 weeks later? After being hauled for replacement of SD? One or both?

So how long in the water to have that much fuzz and stuff?

Depressing, both videos.

I wouldn't go without my galvanic isolator!

[fstbttms]

Originally Posted by ggray

One or both?

Port saildrive leg was replaced.

Originally Posted by ggray

So how long in the water to have that much fuzz and stuff?

A couple of weeks.