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Cathodic Protection for Aluminum Hull - Need Help
Folks,
I will be getting such boat (19') and will be using it in salt and freshwater. Power comes from a merc sportjet. I have been looking into corrosion protection and learned that you should have magnesium in fresh and alumium or zinc in sal****er ... Seems there isnt a good all around thing? Since the hull of this boat will disintegrate if protection isnt done right I was hopeing to gather good advise from here. Merc makes a mercathode to protect their sterndrives. I am not sure if this would be useable on an aluminum hull as it would ground the hull to the battery, which I think isnt good for this type hull. There is also electroguard which makes such devices for large boats.. Does anybody know what is best for my fututre hull & drive? The hull will last forever therfore a few hundred bucks for the right protection is no issue. Thanks for all advise !! :) Matt |
Cathodic Protection for Aluminum Hull - Need Help
"Matt Lang" wrote in message om... Folks, I will be getting such boat (19') and will be using it in salt and freshwater. Power comes from a merc sportjet. I have been looking into corrosion protection and learned that you should have magnesium in fresh and alumium or zinc in sal****er ... Seems there isnt a good all around thing? Since the hull of this boat will disintegrate if protection isnt done right I was hopeing to gather good advise from here. Merc makes a mercathode to protect their sterndrives. I am not sure if this would be useable on an aluminum hull as it would ground the hull to the battery, which I think isnt good for this type hull. There is also electroguard which makes such devices for large boats.. Does anybody know what is best for my fututre hull & drive? The hull will last forever therfore a few hundred bucks for the right protection is no issue. Thanks for all advise !! :) Matt Zinc also works in freshwater, just not as good as magnesium. Sounds like a Willy Predator. Since it will be a trailer boat, just add a couple of decent size zinc's to the hull at the transom and make sure there is one on the bottom of the jet nozzle. My 1991 Jetcraft Bluewater is still going strong. Only corrosion hole is going to be welded Friday morning, and that was from something, probably copper, getting in the anchor locker and the back of the locker collecting a lot of dirt against the bulkhead. Is a 1/8" hole outside and maybe 1/2" at the inside of 0.190 thick aluminum. I run mine in both fresh and salt water. |
Cathodic Protection for Aluminum Hull - Need Help
"Calif Bill" wrote in message hlink.net...
"Matt Lang" wrote in message om... Folks, I will be getting such boat (19') and will be using it in salt and freshwater. Power comes from a merc sportjet. I have been looking into corrosion protection and learned that you should have magnesium in fresh and alumium or zinc in sal****er ... Seems there isnt a good all around thing? Since the hull of this boat will disintegrate if protection isnt done right I was hopeing to gather good advise from here. Merc makes a mercathode to protect their sterndrives. I am not sure if this would be useable on an aluminum hull as it would ground the hull to the battery, which I think isnt good for this type hull. There is also electroguard which makes such devices for large boats.. Does anybody know what is best for my fututre hull & drive? The hull will last forever therfore a few hundred bucks for the right protection is no issue. Thanks for all advise !! :) Matt Zinc also works in freshwater, just not as good as magnesium. Sounds like a Willy Predator. Since it will be a trailer boat, just add a couple of decent size zinc's to the hull at the transom and make sure there is one on the bottom of the jet nozzle. My 1991 Jetcraft Bluewater is still going strong. Only corrosion hole is going to be welded Friday morning, and that was from something, probably copper, getting in the anchor locker and the back of the locker collecting a lot of dirt against the bulkhead. Is a 1/8" hole outside and maybe 1/2" at the inside of 0.190 thick aluminum. I run mine in both fresh and salt water. Hi Bill, thanks for your advice! I will definately add some zincs, but will also look into the cathodic protection. The sportjet uses a SS impeller which accelerates corrosion. On their sterndrives Merc recommends using the Mercathode if a SS prop is used... Matt |
Cathodic Protection for Aluminum Hull - Need Help
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Cathodic Protection for Aluminum Hull - Need Help
I think the only protection that Cathodics are allowed to use is the rhythm
method. |
Cathodic Protection for Aluminum Hull - Need Help
Yeah I suspected this isnt an easy one ... do it wrong and the hull is
gone in no time :( I contacted a manufacturer that makes these things for large vessels .. lets see what they have to offer Mayy The things you're going to run into: Constant power availability and drain, and the system costs more than the boat. |
Cathodic Protection for Aluminum Hull - Need Help
(Matt Lang) wrote in message . com...
(Lee Jones) wrote in message . com... (Matt Lang) wrote in message . com... "Calif Bill" wrote in message hlink.net... "Matt Lang" wrote in message om... Folks, I will be getting such boat (19') and will be using it in salt and freshwater. Power comes from a merc sportjet. I have been looking into corrosion protection and learned that you should have magnesium in fresh and alumium or zinc in sal****er ... Seems there isnt a good all around thing? Since the hull of this boat will disintegrate if protection isnt done right I was hopeing to gather good advise from here. Merc makes a mercathode to protect their sterndrives. I am not sure if this would be useable on an aluminum hull as it would ground the hull to the battery, which I think isnt good for this type hull. There is also electroguard which makes such devices for large boats.. Does anybody know what is best for my fututre hull & drive? The hull will last forever therfore a few hundred bucks for the right protection is no issue. Thanks for all advise !! :) Matt Zinc also works in freshwater, just not as good as magnesium. Sounds like a Willy Predator. Since it will be a trailer boat, just add a couple of decent size zinc's to the hull at the transom and make sure there is one on the bottom of the jet nozzle. My 1991 Jetcraft Bluewater is still going strong. Only corrosion hole is going to be welded Friday morning, and that was from something, probably copper, getting in the anchor locker and the back of the locker collecting a lot of dirt against the bulkhead. Is a 1/8" hole outside and maybe 1/2" at the inside of 0.190 thick aluminum. I run mine in both fresh and salt water. Hi Bill, thanks for your advice! I will definately add some zincs, but will also look into the cathodic protection. The sportjet uses a SS impeller which accelerates corrosion. On their sterndrives Merc recommends using the Mercathode if a SS prop is used... Matt Hi, If I can offer some advice on cathodic protection, never use a magnesium anode on an aluminium hull. Aluminium will corrode much more quickly at high pH and cathodic protection over a certain level will cause this. Aluminium or Zinc anodes are ok, but magnesium has a much more negative potential, which would take the aluminium into the danger zone. Same goes for any sort of impressed current device (connected to battery or other power supply). You would need to be very careful that you don't depress the potential of the aluminium too much. On large craft, ferries and so on, an automatically controlled system is used. Hope this helps lee Thanks Lee! Yeah I suspected this isnt an easy one ... do it wrong and the hull is gone in no time :( I contacted a manufacturer that makes these things for large vessels .. lets see what they have to offer Mayy As it happens, I work for a company who makes systems for large vessels, we have a number of units on large aluminium ferries. Don't worry I'm not trying to sell you something, because the cost would be too prohibitive. A large ferry company has a huge benefit in reduced dry dockings, maintenance etc, but for a small boat it just isn't worth it. There may be someone making small units suitable for your boat, but to be honest, I'd stick with sacrificial anodes, aluminium or zinc. Probably zinc. If you do decide to buy a self powered system, be very careful they know what they are doing and have plenty of experience of aluminium cp. I know of aluminium ships that have had a hole in the hole in a matter of months. Take care Lee |
Cathodic Protection for Aluminum Hull - Need Help
"HLAviation" wrote in message link.net...
Yeah I suspected this isnt an easy one ... do it wrong and the hull is gone in no time :( I contacted a manufacturer that makes these things for large vessels .. lets see what they have to offer Mayy The things you're going to run into: Constant power availability and drain, and the system costs more than the boat. Actually the Mercathode is only about $120 .. it will doesnt use much power and woiuld only have to run while the boat is in the water or if it drains the battery while the motor is running |
Cathodic Protection for Aluminum Hull - Need Help
I'm not real familiar with the system, however I was under the impression
that it was strictly for the drive. "Matt Lang" wrote in message om... "HLAviation" wrote in message link.net... Yeah I suspected this isnt an easy one ... do it wrong and the hull is gone in no time :( I contacted a manufacturer that makes these things for large vessels .. lets see what they have to offer Mayy The things you're going to run into: Constant power availability and drain, and the system costs more than the boat. Actually the Mercathode is only about $120 .. it will doesnt use much power and woiuld only have to run while the boat is in the water or if it drains the battery while the motor is running |
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