# Tips for mooring in Saltwater



## dizzyliz (Nov 26, 2012)

anyone have experience mooring in saltwater. I live on the Chesapeake (upper middle) water is brackish/salt and want to slip the boat. I pulled my fiberglass boat 2 times a season for routine maint/storms and was curious if I could do the same with a 1648.

thanks


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## bigwave (Nov 26, 2012)

Make sure you have a good bottom paint, with a high copper content. This will help slow down the barnical and oysters on the bottom. Once water gets so cold the growth will slow down or stop......come spring they will grow like crazy. Here where I live in central Florida you can get some rapid growth in just a week or so. It is a real PITA scrapping them off.


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## rickybobbybend (Nov 26, 2012)

Others might chime in on this, but in many years of boating on Puget Sound it was common practice to tilt the motor so it was completely out of the salt water when moored.


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## dizzyliz (Nov 28, 2012)

thanks for the feed back. I have a zodiac 310 that i left in for 3-4 weeks and had a mother of a time removing growth. 

I have heard some tinners use epoxy on the bottom then coat with a bottom paint. seems like a lot of work.


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## PSG-1 (Nov 28, 2012)

bigwave said:


> Make sure you have a good bottom paint, with a high copper content. This will help slow down the barnical and oysters on the bottom. Once water gets so cold the growth will slow down or stop......come spring they will grow like crazy. Here where I live in central Florida you can get some rapid growth in just a week or so. It is a real PITA scrapping them off.





+1, except for one thing.

It should be noted that the ONLY type of anti-fouling paint suitable for use on aluminum boats is COPPER THIOCYANATE BASED PAINT, NOT CUPROUS OXIDE! If you paint an aluminum boat with cuprous oxide paint, it will destroy the hull. Interlux Trilux 33, or the equivalent must be used. It is also preferable to initially put down 2 layers of Interprotect Primer, or some other 2-part epoxy primer similar to this, and then the Trilux 33. 

Reason being, the anti fouling paint is ablative, meaning it wears down with use. If you don't have primer under this, then, any exposed areas are just that, exposed areas of unprotected surface. The Interprotect is a very good primer that is rated for use on all metals above and below the waterline, and will insure that the hull is properly protected.

Additionally, even though there are zinc anodes on your engine, no boat manufacturers provide any galvanic protection, i.e. a zinc anode mounted to the hull. You should install a zinc anode on your boat, and have it connected to the bonding wire of the engine, if one is available. If not, then run a bonding wire between the zinc anode and the negative terminal of the battery. The bonding wire can be made of some stainless wire, such as 1/16" wire rope, or even fishing leader, with ring terminals on each end.

To mount the zinc, you'll need 2 bolts, 6 fender washers, 2 regular nuts, and 2 nylock nuts, all stainless steel. Make sure the bolts are long enough to pass through the thickness of your hull, the thickness of the zinc, and allow for extra thickness for the lock nut, and the nut that will be tightened to the hull, and then also allow for the thickness of a backing plate, which will mount to the outside of the zinc...I'll explain this in a minute.

Drill the 2 holes for the mounting bolts in the transom, below the waterline. The hole pattern should coincide with the mounting holes of your zinc, depending on which one you want to use.

Now, place a fender washer on each bolt, and coat the surfaces with RTV Ultra Black, 5200, or another good sealant, do NOT use regular silicone. Place the bolts through the holes, from the inside of the boat. Then, from the outside, install another fender washer and sealant on the bolts protruding from the hull. Then, screw a nut (regular nut) onto each bolt, and tighten down. 

At this point, you should have 2 studs sticking out of the transom. Place the zinc onto these studs. Now, you will need a strip of aluminum about 1.5"-2" wide, by about 1/8" thick, with the same hole pattern as the zinc. This is your backer plate. It is important to use this, because the zinc will first erode around the mount holes. Once it erodes large enough, it will fall off, leaving the boat with no protection. The purpose of the backer plate is to prevent this.

Once you have installed the zinc and backer plate, place the last set of fender washers onto the bolts, and then the ring terminal for the bonding wire goes onto one of the bolts. Lastly, install the lock nuts.

When installed in this manner, you can easily change the zinc, without having to remove bolts and re-seal everything.

For a 16 foot johnboat, you'll need about 32 square inches of galvanic protection, or a zinc about 4x8"

Be sure to regularly inspect your zinc, keep a good coat of paint on the boat, keep a functioning bilge pump (or two) with float switches (but never rely on them, always check your boat after a heavy rain) and haul out at least 3-4 times a year, only if for a day or two, just to give it a good freshwater rinse, flush the engine, inspect zincs, change lower unit lube, fog the engine with some Sea Foam spray, and attend to any other details........... and you will have no problems.

This comes from someone who has kept boats in saltwater for the last 30 years, and has the experience of the right way and the wrong way to do it. Thus, therefore, all the recommendations for the correct bottom paint and galvanic protection. 

I've seen what happens when this SOP is NOT followed, and it ain't a pretty sight! Holes in the boat large enough to put your hand through. And that's not an exaggeration.


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## Captain Ahab (Nov 29, 2012)

Make sure you have a master battery disconnect switch or you could slowly arc weld through your boat


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## bigwave (Nov 29, 2012)

PSG-1 said:


> bigwave said:
> 
> 
> > Make sure you have a good bottom paint, with a high copper content. This will help slow down the barnical and oysters on the bottom. Once water gets so cold the growth will slow down or stop......come spring they will grow like crazy. Here where I live in central Florida you can get some rapid growth in just a week or so. It is a real PITA scrapping them off.
> ...


Very Informative PSG, I assumed that most people know to put a good primer and or paint on before you use any type of bottom paint. I forgot all about the copperous oxide and aluminum........I knew that pettit made a bottom paint for aluminum and also assumed that anyone would look for the bottom paint for aluminum. SeaHawk also makes a bottom paint just for pontoon boats.......and as you also said, there is naturally occurring galvanic corrosion in any body of saltwater. Thanks for the explanation.


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## cva34 (Nov 29, 2012)

Thanks PSG /very informative and understandable cva34


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## PSG-1 (Nov 29, 2012)

Not a problem, glad to give a little advice to help extend the life of aluminum boats kept in saltwater. 

The manufacturers don't want you to know this stuff, because they want you to buy another johnboat every 3 years. Which is exactly why the SOB's don't have a provision for a zinc anode on their boats!

Sure, the lower unit of the motor has one, but once you trim it out of the water, well, it really doesn't need galvanic protection....duh! #-o And having that zinc out of the water leaves your boat at the mercy of electrolysis, not that the tiny zinc used on the motor would be enough coverage for the entire boat.

To clarify my rather lengthy explanation of how to mount your boat's zinc.....here's a picture of the zinc anode on my boat, I snagged it from my thread on my Triton 1650SC modification:





In this photo, you can clearly see the backing plate, as well as the bonding wire. The 2 smaller bolts to the outside edges are the actual mounting bolts that hold the backer plate to the transom. The zinc is bolted to the backer plate with the 2 larger bolts shown in the center. And the bonding wire is connected to the factory bonding wire, they will usually have it connected to the anode mounting bolt on the underside of the PT unit, as shown in the example above. There will also be a factory bond wire along the engine shaft, and also one connected to the powerhead. 

Through the powerhead connection, this is the final loop of the circuit which will carry stray current back to the battery's negative terminal, as the negative is the CATHODE, not the ANODE side of the battery. This helps to cancel out stray current, and give it a path to run through, instead of your hull or other critical components.

I generally keep numerous johnboats in the saltwater year round, and have done so for about 30 years. Only the last 10 of which, I have began using anodes on the boat, and maintaining a layer of bottom paint. And through the comparative analysis, I can say with certainty, the paint and the zinc will greatly extend the life of your boat.

And remember the correct material for anodes....

salt water use: ZINC

fresh water: MAGNESIUM

brackish: ALUMINUM 




Hope this helps.


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## PSG-1 (Nov 30, 2012)

bigwave said:


> Very Informative PSG, I assumed that most people know to put a good primer and or paint on before you use any type of bottom paint.



Well, I didn't know any better, until just a few years ago. Being somewhat of a cheap-ass, I used to just put bottom paint on the boat, with no primer. This doesn't work too well. #-o 

I'm sure they may be other cheapskates like me out there, who don't want to spend the 100 extra dollars on good primer, but it is a necessary thing. Also, as the paint made for aluminum is about twice as expensive as fiberglass paint, a lot of people try to go the cheap route here, and this is absolutely where the extra money needs to be spent, on the correct paint. I can't tell you how many boats I've seen where the owner tried to be cheap and used the wrong paint, destroying their hull. 

As much as I hate to admit it, I was one of those people, and had to re-build the bottom in my 14' duracraft, where electrolysis completely destroyed the center V, kinda like it was on my 16' Dura Craft.


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