james, I am not familiar with the Maramu, but the SN and the SM have the bonding connection to the keel with a copper stripe that goes to a keel bolt in the bilge. there is an excellent documentation how to exchange that by our Bill Rouse that helped many of us to replace the corroded stripe.

look at this...

https://groups.yahoo.com/neo/groups/amelyachtowners/photos/albums/138287824

 

fair winds,

herbert, SN120, Trinidad