Anodes - gh26
Posted: Tue January 12th, 2021, 9:12 am
Hi all
I had the steel keels of Iris shot blasted, and refinished in 3 coats of 'Jutonmastic 90' - an epoxy 2 pack marine primer. Looks a great job - havent antifouled yet.
The previous zinc anodes did a great job on these wings - there were 2 bolted through each, with the metal cleaned in direct contact and I didnt have much pitting - indeed, most of the original galvanization was still in place.
However, now I have epoxied the surface, I am not so keen on cutting it back round the anode.
I have some old 'Arc' copper multiply welding wires from a heavy duty machine - heavily lugged and each about 15 ft log, and perhaps 8mm thick. I was thinking of bolting these to the keels on the inside, and running them back to a large anode fitted in the stern. Good idea - or should I grind the epoxy?
On a second note. The aft anode (a double bolted affair) had 2 wires comming off it. One is attached to the engine bell housing (and looks like a diy job fitted later), while the other had broken off completely and I dont know where it went! The whole wire was in the bilge. Now, the engine is a volvo penta MD 2020, in good shape. According to my reading of the workshop manual, the engine should be 'galvanically isolated - they are not to be connected to an anode. The drive shaft has a plastic thrust coupling, and the alternator and starter have direct negative connections - so I can see that it could be so. The stern gland was replaced before I bought the boat. The question would be then - should the anode be connected to the stern bronze drive flange - and then - what about the prop - it would usually be isolated with the rubber in the cutlass bearing. There is no anode on the driveshaft....
I had the steel keels of Iris shot blasted, and refinished in 3 coats of 'Jutonmastic 90' - an epoxy 2 pack marine primer. Looks a great job - havent antifouled yet.
The previous zinc anodes did a great job on these wings - there were 2 bolted through each, with the metal cleaned in direct contact and I didnt have much pitting - indeed, most of the original galvanization was still in place.
However, now I have epoxied the surface, I am not so keen on cutting it back round the anode.
I have some old 'Arc' copper multiply welding wires from a heavy duty machine - heavily lugged and each about 15 ft log, and perhaps 8mm thick. I was thinking of bolting these to the keels on the inside, and running them back to a large anode fitted in the stern. Good idea - or should I grind the epoxy?
On a second note. The aft anode (a double bolted affair) had 2 wires comming off it. One is attached to the engine bell housing (and looks like a diy job fitted later), while the other had broken off completely and I dont know where it went! The whole wire was in the bilge. Now, the engine is a volvo penta MD 2020, in good shape. According to my reading of the workshop manual, the engine should be 'galvanically isolated - they are not to be connected to an anode. The drive shaft has a plastic thrust coupling, and the alternator and starter have direct negative connections - so I can see that it could be so. The stern gland was replaced before I bought the boat. The question would be then - should the anode be connected to the stern bronze drive flange - and then - what about the prop - it would usually be isolated with the rubber in the cutlass bearing. There is no anode on the driveshaft....