Newbie copper painting underside of boat

[durban131]

Hello All,

Im a relatively new boat owner and last year for the first time I docked my boat in salt water (Boston Harbor). After a couple months lots of green algea growth appeared all over the bottom of the boat inhibiting its movement thru the water. I did some research and discovered that when storing your boat in salt water, your supposed to paint the underside with a copper paint to discourage growth. Many of you are probably shaking your heads but I simply did not know this.

Before I take the boat out of winter storage this year I want to do a proper paint job on the underside. This is a task I would like to do myself, but I havent found much luck with any good online tutorials. Anyone know of any or have any other input? Any advice of much appreciated. Thanks.

 

[Chris1956]

Re: Newbie copper painting underside of boat

The best way to paint is as follows. Hopefully you have cleaned the bottom of the boat well. Use some masking tape to mark the waterline on the hull. Now use some primer made for anti-fouling paint, as the first coat. Pettit makes a "sandless" primer, which works well, but there are others. Sometimes the primer has a minimum and maximum effectiveness timetable. A single coat is usually enough. Now apply two coats of a multi-season ablative antifouling paint. Ask someone in your marina, what kind to use, as it is local knowledge that is best. With the paint still wet, pull off the masking tape. You should be protected from slime/barnacle/and other stuff for 2 years, but you will likely need to touch up next year.

 

[durban131]

Re: Newbie copper painting underside of boat

The best way to paint is as follows. Hopefully you have cleaned the bottom of the boat well. Use some masking tape to mark the waterline on the hull. Now use some primer made for anti-fouling paint, as the first coat. Pettit makes a "sandless" primer, which works well, but there are others. Sometimes the primer has a minimum and maximum effectiveness timetable. A single coat is usually enough. Now apply two coats of a multi-season ablative antifouling paint. Ask someone in your marina, what kind to use, as it is local knowledge that is best. With the paint still wet, pull off the masking tape. You should be protected from slime/barnacle/and other stuff for 2 years, but you will likely need to touch up next year.

Exactly the kind of description I was looking for. Thank you Chris1956.

 

[H20Rat]

Re: Newbie copper painting underside of boat

First question is do you really want to wet-slip your boat? A typical small I/O bowrider isn't the best boat to wet-slip. Its tough to cover well, it doesn't stand up to elements if exposed, and worse yet, you have an outdrive that could sink your boat at the dock with really no warning.

Find a marina that offers a parking spot (or rack storage), it will be cheaper than a wet slip and your boat will stay in far better shape! The time to load/unload is minimal once you have a routine down.

Lastly, once you bottom paint, you aren't going back to just gelcoat very easily.

 

[durban131]

Re: Newbie copper painting underside of boat

First question is do you really want to wet-slip your boat? A typical small I/O bowrider isn't the best boat to wet-slip. Its tough to cover well, it doesn't stand up to elements if exposed, and worse yet, you have an outdrive that could sink your boat at the dock with really no warning.

Find a marina that offers a parking spot (or rack storage), it will be cheaper than a wet slip and your boat will stay in far better shape! The time to load/unload is minimal once you have a routine down.

Lastly, once you bottom paint, you aren't going back to just gelcoat very easily.

All very valid point.

I live in Boston and for the first year I had the boat I dry stored it. However 90% of the time I was just ended up trailer launching it into Boston Harbor. Unfortunately this city doesnt have any good boat ramps and trailer launching and loading here is a huge hassle when solo. Sometimes I just want to dart around the harbor, take my step son fishing, or have a sunset cruise, but the idea of picking up the boat, trailing it to ramp, launching it and then loading upon return just made the whole thing seem not worth it.

Then the next year (last year) I docked it and it made it exponentially easier to take the boat out at any time. Especially if I just felt like going out on a whim. But I also still have the freedom to trailer it to freshwater which I do every now and then.

You know I never thought of the outdrive issue you speak of but that does now have me a little concerned. I always knew there was something I liked about my style boat with the outboards, and now I think I know why. :facepalm:

I guess I just have to weigh the pros and cons of each.

Wet Dockage
Pros: ease of launch into harbor (huge)
Cons: exposure to weather, outdrive damage could sink boat at dock, need to paint

Dry Dockage
Pros: ease of departure when trailering to freshwater (rare), protected against weather
Cons: huge hassle when taking boat into harbor (often)

Thanks for the input smokingcrater, I guess I have a little to think about.

 

[JoLin]

Re: Newbie copper painting underside of boat

There's another (possible) option. Rack storage. The marina lifts the boat out of the water and puts it above ground in a storage rack. You call ahead to tell them to splash it before you get there. I've seen it a lot down south, but it isn't very common on L.I. Don't know if you have that option in Boston.

 

[H20Rat]

Re: Newbie copper painting underside of boat

You know I never thought of the outdrive issue you speak of but that does now have me a little concerned. I always knew there was something I liked about my style boat with the outboards, and now I think I know why. :facepalm:

I/O's have bellows that seal the drive to the engine/transmission. They are rubber, and need to be replaced every so often. When they crack, they tend to let it A LOT of water in a hurry. Think of it this way. Your boat stays afloat because of relatively waterproof fiberglass, has nice high sides, has a bilge pump, etc. The most critical part is a relatively large piece of fairly thin rubber that you can't even see. One failure in that and nothing else matters.

(marine growth can also cause relatively new bellows to wear or puncture)

 

[Thalasso]

Re: Newbie copper painting underside of boat

You don't want copper. Copper and Aluminum are too far apart on the galvanic scale to be compatible and using copper based anti-fouling paint on aluminum parts will cause galvanic corrosion. Use whatever you like on the hull.Use a paint designed for aluminum surfaces on the overdrive parts. It is also best to only bring the copper based paint up within 1" or so of the overdrive itself just use 1" wide blue painters tape and keep the Cu based paint away from the aluminum.


You want to do it right? After sanding with 80 grit paper you need to apply a barrier coat and then a primer (2 coats) then bottom paint.
Temp and humidity all come into play when doing this along with time periods to apply next coat.

Marine growth isn't going to puncture the bellows by any means.

 

[crabby captain john]

Re: Newbie copper painting underside of boat

Everyone needing bottom paint wants to do it themselves ~~~ once.

Indoor dry stack ~~ only way to go!

 

[Home Cookin']

Re: Newbie copper painting underside of boat

First question is do you really want to wet-slip your boat? A typical small I/O bowrider isn't the best boat to wet-slip. Its tough to cover well, it doesn't stand up to elements if exposed, and worse yet, you have an outdrive that could sink your boat at the dock with really no warning.

Find a marina that offers a parking spot (or rack storage), it will be cheaper than a wet slip and your boat will stay in far better shape! The time to load/unload is minimal once you have a routine down.

Lastly, once you bottom paint, you aren't going back to just gelcoat very easily.

This is such a picture of the "country mouse/city mouse" story except it's "lake boater/coastal boater."

Your first sentence is so true for all boaters, but not as you intended...

Your second sentence, if it were written by a coastal boater, would be "find a dealer, sell the I/O and get a boat that can stay in the water uncovered, hold up to outdoor use and stay afloat!"

Your third sentence: why would anyone go back to gelcoat, even if he decided to dry-store the boat?

Viva la difference'

 

[tpenfield]

Re: Newbie copper painting underside of boat

I bottom paint my salty water boat every year. You also want fresh anodes and anti-fouling paint for the outdrive. Yes outboards are better in that regard, because you can tilt them up out of the water when not in use.

i have used the copper based paints with decent results . . . In the past 12 years or so, I switched to a more Eco-friendly paint. EPaint EP-2000.


the biggest issue would be sure to get all of the marine growth off the hull and outdrive from last year. Did you get any barnacles . . . Or just algae?

Anyway, lots of boats stored in salt water and they get bottom paint. Just part of the 'fun'.

if your hull is bare, then you may want to put a barrier coat on it prior to the anti-fouling paint. Interlux Interprotect 2000E comes to mind as a good barrier coat.

i usually mask up about 4-6" above the water line, so that the boat does not grow a bread over the summer.

 

[H20Rat]

Re: Newbie copper painting underside of boat

Your first sentence is so true for all boaters, but not as you intended...

Your second sentence, if it were written by a coastal boater, would be "find a dealer, sell the I/O and get a boat that can stay in the water uncovered, hold up to outdoor use and stay afloat!"

Your third sentence: why would anyone go back to gelcoat, even if he decided to dry-store the boat?

1) true no matter how you take it...
2) Pretty sure that is what I said. not quite as direct as that, but heavily hinted that a bowrider might not be the right boat choice.
3) Resale... That particular boat with bottom paint is worth less than it was the day before it was painted. Plain and simple, its a trailer boat. Trying to make it into something it isn't doesn't help the value any.

(btw, because of unusual work circumstances, roughly half of my boating last year was coastal... )

 

[Home Cookin']

Re: Newbie copper painting underside of boat

OK now we are on the same page!

 

[durban131]

Re: Newbie copper painting underside of boat

You don't want copper. Copper and Aluminum are too far apart on the galvanic scale to be compatible and using copper based anti-fouling paint on aluminum parts will cause galvanic corrosion. Use whatever you like on the hull.Use a paint designed for aluminum surfaces on the overdrive parts. It is also best to only bring the copper based paint up within 1" or so of the overdrive itself just use 1" wide blue painters tape and keep the Cu based paint away from the aluminum.


You want to do it right? After sanding with 80 grit paper you need to apply a barrier coat and then a primer (2 coats) then bottom paint.
Temp and humidity all come into play when doing this along with time periods to apply next coat.

Thanks for these bits of information. Much appreciated.

 

[durban131]

Re: Newbie copper painting underside of boat

I must say that after doing some research, I think rack storage is absolutely NOT the way to go for someone like me.

First and foremost I simply think we dont really have that option in the Boston area, but secondly, Im the kind of person that on a nice day after work, Ill just want decide on a whim to take the boat out. Or maybe Im getting a drink and meet a lady and convince her to take a sunset set cruise with me. Regardless, I would say a significant majority of my boating is unplanned and I hear nothing but horror stories online about calling the marina ahead, taking time to unload the boat, or it being closed at certain hours, yada yada yada.

I would much rather just trailer the boat than rack store it for that ability to go out on a whim, at any time of day (or night).

 

[s.hadley81]

Re: Newbie copper painting underside of boat

Don't let anyone scare you away from slipping a boat if your gonna use it (have the time and $)and are someone who keeps up on your maintenance it's the way to go I slipped my boat the last two years and use it 100 times more then I would trailering but with the convience of slipping your boat also come more precautions and maintenance I would definitely consider painting the bottom and automatic bilge pump (I got two just to be safe ) , an on board charger (if slip has power) , cover , and make sure you replace your zincs every season there is a lot more to consider when keeping your boat in the water but just like everything it will come with time and experience and don't hesitate to post questions or concerns Guys are more than willing to give info (I know I miss some things )

Good luck and happy boating