Transom mounting bracket Anodes

[Met eish !]

I am running an 8m Rib with 2 X 2015 lean burn DF 90 Suzuki's, the transom Anode on the mounting bracket only lasts 2 months and it's completely corroded away. This has happened twice in 6 months the Rib is permanently on a mooring, the 2 batteries have been earthed I don't have an isolator switch to switch the power off of the motors. I have another 8 m Rib also on a mooring with 2 X 80 4 stroke motors and those anodes last more than a year. I can see bad corrosion on the 90's Suzuki's with only 750 OH. Please help me solve my problem regards Met eish !

 

[alldodge]

Howdy

So both ribs are moored the same way but only the 90's is showing all the erosion.

How are they moored, buoy with chain or cable, or slip?
What do you mean by the batteries are earthed?
Is the rib with the 80's have a battery switch?

 

[Met eish !]

Hi sorry for the late reply been under water for a while !!

90's showing all corrosion both moored the same way chain to buoy and 50mm rope 4m long tied to rope on bow eye.
When having 2 batteries it's advised to earth the 2 negatives with a battery cable.
The rib with the 80's and the 90's does not have battery switches the rib with the 80's only has 1 battery

Cheers

 

[alldodge]

Earthing is grounding, ok I get it

Assuming your in slat water, are the anodes zinc or aluminum? Zincs are good but Aluminum is proving to last longer. and offer better protection.

You can also add zinc/aluminum's by attaching a wire to the them and then connect to the motor earth connection.

Things that can cause an increase in corrosion is dissimilar metals. It also helps if the earth connection is disconnected because it may be attracting currents.

Also look close at the other rib not showing all the issues to see if it is corroding on the motor itself. If the motor is having issues then the anodes are not protecting it as well