anodes

[freedive]

when using anodes on my other boats , which were inboards , ive always used a thansom zinc . the 68 bertram i am redoing has no signs of ever having one . is that because of the anodes located on the 2 outdrives , and are they sufficient enough ? the boat will have fishfinding electronics , anchor hauler and some lighting for electrical equip. trying to keep it simple and basic . got dead ended wires and switches all over the place , trying to eliminate and rip out unused stuff . back to the zincs would i need a transom plate .

 

[alldodge]

Boats that sit in the water need anodes. The type (zinc, aluminum) depends on hull and drives.

Outdrives are made of aluminum and most need aluminum anodes to help protect. The boat also needs a Mercathode or other for best results

 

[freedive]

when this mess is completed , it will be going to marathon fl. and on a lift . im hearing good and bad about the mercathode system . can't tell if its working or not . at least zincs get eaten up and you can actually see when they have to be replaced .

 

[alldodge]

The Mercathod system works if its working properly. Only way to know if it is is to measure with a digital meter and a special probe.



Fresh Water Areas -
620 - 1180 Millivolts with Digital Meter
Salt, Polluted or Mineral Laden Water Areas:
750 - 1180 Millivolts with Digital Meter

And Note: more anodes does not mean more protection, actually it can mean less

That said, staying on a lift its a non-issue

 

[freedive]

then i guess a transom xinc isn't needed . i've noticed that none of the through hull brass fittings ( raw water cooling for engines etc. ) aren't grounded . shouldn't they each have a tail going to a ground buss .

 

[alldodge]

Inboards use transom zinc, I/O don't because they need them on the drive

Yes there should be ground wires on brass thru hulls, and it should also have a galvanic isolator. But being on a lift the isolator will not be used

 

[dingbat]

i've noticed that none of the through hull brass fittings ( raw water cooling for engines etc. ) aren't grounded .

I would hope they are bronze, not brass.

Bronze (copper (88%) and tin (10-12%) alloy) is fairly stable.
Brass (zinc (34%) and copper (66%) alloy) is highly reactive and should never be used on a boat.

Any thru hull below the water line should be bonded.
Bonding thru hulls above the water line may cause more problems than it solve.

 

[freedive]

i stand corrected . they are bronze . im referring to just the the fittings that are below the water line . i see the screws on these through hull fitting but none have a wire connected . not sure of the wire size , was thinking #8AWG with a soldered connecter and heat shrink with copper coat on fitting bolt for good electrical conductivity . the other end to a bond buss somewhere on the transom . does this sound about rite . never would have seen the missing bonds with out yanking both engines .

 

[alldodge]

Brass/Bronze its a thru hull
Don't see 8 more like 12

http://stevedmarineconsulting.com/wp-content/uploads/2014/03/BondingSystems138_05.pdf

 

[freedive]

i noticed the garboard drain plug doesn't have a provision on it for bonding does this mean it doesn't have to be bonded ? i found the mercathode section in the forum and am reading through it now .

 

[freedive]

i read the mercathode section in the forum , and also sterndrives .com ( by mercury ). what i am understanding , its for galvanic corrosion . if the boat is high and dry on a lift , then there should be no corrosion occurring for the lack of the electrolite (salt water ) . so can the cathode system be on the load side of the battery switch , so its not in use while up on the lift .the salinity in the keys is higher than here in NY

 

[alldodge]

Yes

 

[freedive]

my daughter sad you put an attachment in your reply clicked on it so im reading through it . you'll have to excuse me , im not very good with computers . just a freaking old guy

 

[freedive]

i finished the attached article . good information , but how do you know what size the hull zinc has to be . was thinking a for a 25" boat like mine , a 4" X 6" x 3/4" zinc should be about rite size for transom .would you have any ideas .

 

[alldodge]

You mentioned this boat has outdrices? 1st post
If it does then all you need is what is on the drives. Start there and measure voltages. That said the boat needs to sit in the water connected to shore power for at least 24 hours prior to measuring

 

[freedive]

didn,t know the anodes on the outdrives were al that is needed . had a 24" 1971 seabird with twin OMC outdrives , and this boat had 2 hull zincs besides the outdrive zincs . thats why i was questioning it .

 

[freedive]

thanks for your time and helping out

 

[KJM]

I would hope they are bronze, not brass.

Bronze (copper (88%) and tin (10-12%) alloy) is fairly stable.
Brass (zinc (34%) and copper (66%) alloy) is highly reactive and should never be used on a boat.

Any thru hull below the water line should be bonded.
Bonding thru hulls above the water line may cause more problems than it solve.

Does that include the garboard drain? Is this for any boat or just inboards or I/O's?

 

[dingbat]

Due to its high zinc content, brass should not be used on any boat.

Better to avoid a known problem than install and hope for the best

 

[alldodge]

Been looking around and I'm unable to remember if the one on my Formula had a bonding wire on the garboard, but don't think it did. Would be easy enough to do, use a machine screw in one of the 3 holding it, and attach wire to the inside.

There are some (not a lot) write ups on other forums about it giving out over time, all of them were in salt.