Fresh water to salt water

[shinsr]

I posted this as an add on to a old thread I found, but realized I may get a quicker response if I post as new. So please excuse the duplicate - I (subject to survey) will be getting a '08 48da from fresh water (lake Champlain) and bringing it down its own bottom to Long Island. Boat is in Bristol condition all around. Question relates to bottom paint - I have read that over time ablative paint will lose its effectiveness in fresh water. Question is how quickly that happens. If I have the bottom redone (sanding and 2 fresh coats of hydro coat) along with new zincs before she launches up north I save on a haul, block and relaunch when she is back home. Boat will likely sit in fresh water 3-4 weeks before coming home, any thoughts if that is too long to impact ablative properties of paint? Where I boat the growth can get bad mid summer without a good bottom and don't want to take a risk. Thanks in advance. Russ.

 

[fwebster]

The ablative paint doesn't really lose its effectiveness as much as the metals in the paint oxidize and get covered with fresh water algae. You can prevent that from being much of an issue if you pressure wash the hull when you remove the boat from freshwater while it is still wet then keep the boat clean after you launch the boat in saltwater.

 

[ttmott]

I posted this as an add on to a old thread I found, but realized I may get a quicker response if I post as new. So please excuse the duplicate - I (subject to survey) will be getting a '08 48da from fresh water (lake Champlain) and bringing it down its own bottom to Long Island. Boat is in Bristol condition all around. Question relates to bottom paint - I have read that over time ablative paint will lose its effectiveness in fresh water. Question is how quickly that happens. If I have the bottom redone (sanding and 2 fresh coats of hydro coat) along with new zincs before she launches up north I save on a haul, block and relaunch when she is back home. Boat will likely sit in fresh water 3-4 weeks before coming home, any thoughts if that is too long to impact ablative properties of paint? Where I boat the growth can get bad mid summer without a good bottom and don't want to take a risk. Thanks in advance. Russ.

That's the way I'd do it. I use Hydrocoat SR which seems to be a very good product in our area. Running the boat home will scrub the bottom and for a month or so zincs should be OK.

 

[mnm99]

I too am in contract with the survey happening this Tuesday. It is also in Lake Champlain and am bringing it back to the long Island sound if all goes well. Having it dropped in New Baltimore then taking it the rest of the way. I'm having the mechanic paint it with 1 coat of CSC Interlux and install Aluminum Zincs before it's shipped. It should be fine for the season. Good luck..

 

[shinsr]

I too am in contract with the survey happening this Tuesday. It is also in Lake Champlain and am bringing it back to the long Island sound if all goes well. Having it dropped in New Baltimore then taking it the rest of the way. I'm having the mechanic paint it with 1 coat of CSC Interlux and install Aluminum Zincs before it's shipped. It should be fine for the season. Good luck..

Dont think you want aluminum zincs if headed to salt water for good - you want full zinc zincs.

 

[shinsr]

Thanks all for input - gave them the green light for the bottom job - looks like it will only be in fresh for 2 weeks now and a three day trip home should clear up any minor algae if anything at all. Added in new zincs and a full hull wax so I shouldn't need any hauls once she is home. Good luck mnm with your trip, sounds like you will be ahead of me. My survey is on the 25th and if all goes well start her home on may 11th.

 

[mnm99]

Dont think you want aluminum zincs if headed to salt water for good - you want full zinc zincs.

Why? Any reason not to? Just wondering what your backing is?

Read.... http://www.performancemetals.com/anodes/AnodeFAQs.shtml

Q. What do sacrificial anodes do?
A. All metals immersed in an electrolyte (sea water for example) produce an electrical voltage. When two dissimilar metals are in contact (electrically connected) they produce a galvanic cell (like a battery), with the less noble metal (a bronze propeller for example) forming the anode and the more noble metal (stainless steel shaft) forming the cathode.
Aluminum anode alloy provides more protection and lasts longer than zinc. It will continue to work in freshwater and is safe for use in salt water. Aluminum is the only anode that is safe for all applications.

 

[ttmott]

Why? Any reason not to? Just wondering what your backing is?

Read.... http://www.performancemetals.com/anodes/AnodeFAQs.shtml

Q. What do sacrificial anodes do?
A. All metals immersed in an electrolyte (sea water for example) produce an electrical voltage. When two dissimilar metals are in contact (electrically connected) they produce a galvanic cell (like a battery), with the less noble metal (a bronze propeller for example) forming the anode and the more noble metal (stainless steel shaft) forming the cathode.
Aluminum anode alloy provides more protection and lasts longer than zinc. It will continue to work in freshwater and is safe for use in salt water. Aluminum is the only anode that is safe for all applications.

Yes except - Aluminum has a galvanic capacity of 1108 Amp Hours per pound where Zinc has 368 Amp Hours per pound. Sea Ray designed the galvanic bonding of their boats in sea water using Zinc. If you desired to change to aluminum the anode loading will have to be evaluated to ensure the boat is not over or under "zinc'd". Too much anode and the boat will blister and too little the running gear will erode.

 

[mnm99]

Yes except - Aluminum has a galvanic capacity of 1108 Amp Hours per pound where Zinc has 368 Amp Hours per pound. Sea Ray designed the galvanic bonding of their boats in sea water using Zinc. If you desired to change to aluminum the anode loading will have to be evaluated to ensure the boat is not over or under "zinc'd". Too much anode and the boat will blister and too little the running gear will erode.

Almost all my friends with a Searay uses Aluminum. None of them have any problems with anything you listed also. Maybe it depends what running gear. Have you personally seen a problem with someone using Aluminum?

Inboard boats with mainly bronze and stainless metal parts can be protected using zinc or aluminum anodes. Don’t worry about overprotecting them. You are only overprotected when the weight of the anodes is so great that your boat sinks! The voltage generated by zinc or aluminum anodes will not cause any damage – no matter how much anode material is added,the maximum voltage that can be generated is the voltage of the anode itself. You could also use magnesium in fresh water locations on fiberglass-hulled boats. Be careful using magnesium on aluminum or wooden hulled boats since you can overprotect them. Steel hulls can also be overprotected to the point where excessive protection voltage rapidly lifts the paint off the hull.

 

[shinsr]

I was simply going on the advice of my Surveyor and my marina - both said I should go with zinc. I have always used Zinc and never had an issue, so I am sticking with that.