• Annnnnnd we're back! Got questions, suggestions, or comments, Guest? Post them here!

Bottom Paint Blues

Jan 22, 2008
127
Hunter 27_75-84 Wilmington, NC
Hey, would like some feedback on bottom paint. Have had h27 '84 for 12 years, located on Cape Fear River about 25 miles from ocean, but still tidal and brackish. I have always pulled the boat every 3 years to do maintenance and bottom paint. Have used 2 coats of Interlux Ultra each time. Usually I paint the blue color, but last April painted the black, which looked good. Typically, the first year and a half, the bottom stays spotless and smooth, then during the 3rd year, I'll brush a few times to keep clean. This time, after only 16 months, the bottom was THICK with barnacles and lots of black weeds.
Spent over 2 hours scraping the barnacles off yesterday - very tiring without SCUBA. The only variable I can see is the color. Would the black paint be so less effective - I know will absorb more sunlight, but yikes! Feedback?
 

Attachments

Feb 26, 2011
1,129
Achilles SD-130 Alameda, CA
Darker colors tend to have higher copper content, as copper affects the color. This is why you will never see a white paint with 60% copper.

That said, I have never noticed any difference in anti fouling performance between various colors of a given product line.
 
Jan 2, 2014
69
Hunter 340 long beach ca
I owned a sea ray power boat for years in fresh water. It was sold to me with black bottom paint. I was not sure what type it was so when my wife and I decided to take the boat to the ocean for a summer, I sanded the bottom off and recoated with west marine copper technology black. After two summer months in long beach waters I could not figure out why the boat had lost all it's power, with two 320 hp motors I should be able to get more than 10 knots. When I dawned my scuba gear and went to look at the bottom, I had "Easily" 1 inch thick white worm over 95% of the bottom. It took 2 tanks of air and as many plastic scrapers to get it clean. We have since purchased a sailboat wich has blue bottom paint ( not sure of mfgr). This summer I have not had any white worm at all--- "0". Could be weather, could be sum thin else? From now on I'm using blue bottom paint though.
 
Feb 26, 2011
1,129
Achilles SD-130 Alameda, CA
The paint you used was not suited to the fouling conditions. The color had nothing to do with it. Thats like saying one car is faster than another because it is painted red. If you base your future anti fouling paint choices based on the assumption that blue means superior anti fouling properties, you are destined to be disappointed.
 
Jan 2, 2014
69
Hunter 340 long beach ca
Now that you mention it, the fastest car I ever owned was red. Sorry, just had to add that, it's true. If that is your opinion I respect that, it would not be the first time I was mislead by an "Expert" at the west marine counter!

That said, I will still recoat my boat with blue paint while throwing salt over my left shoulder and knocking on wood. Will let y'all know how it comes out when it happens.
 
Feb 26, 2011
1,129
Achilles SD-130 Alameda, CA
So it is your contention then that the only problem with the West Marine paint you used that apparently performed so poorly was that it was not blue in color?
 
Feb 14, 2005
4,775
Tayana 37 cutter; I20/M20 SCOWS Worton Creek, MD
amcmahon -
What you describe is becomming more and more quite common for boats kept in brackish water along the MidAtlantic Coast. Probably has nothing to do with the color.

For boats kept on the Upper Chesapeake where the fresh water goes toward the ocean on TOP of the salt water coming IN and under the fresh ... and there is constant but variable upwelling of the saline and mixing with the fresh .......

The Micron EXTRA (corrected/edited as was first erroneously posted as Micron ULTRA) seems to do 'fine' for the first year or so in keeping the slime under control, especially if the boat is kept in water that is 'flowing' and water that has low 'turbidty'. After that time the slime control compound seems to become ineffective and then when the water has high turbidity ('the browns') slime build up is rapid and then further stops the leach out of the anti-slime compound. The accumulation of slime allows the goose barnacles to gain a 'foothold' and once that starts, the buildup of barnacles is quite rapid. The thicker the slime buildup the faster the attachment of the goose barnacles. All this is dependent on the mix of the fresh/salt water, the amount of water flow, and especially the amount of 'turbidity' of the water at the time ... and it differs from month to month and if the season is wet or 'drought-like' and how the different stratifications of water are 'turning over' and mixing .... every damn season is different.

The remedy seems to be: once slime starts to build up you really have get it off the boat as fast as possible, faster if the bottom paint doesnt have the anti-slime compounds. Scrubbing 'harshly' with stiff brushes or 'scrubby pads' seems to reactivate the surface especially the anti-slime compounds but not for all that long. Moving the boat to 'swifter' water also helps. The more 'turbid' the water, the more the frequency of scrubbing is needed once the anti-slime compound starts to fail.
My solution is to put on a thin overcoat of Interlux-EXTRA each season; and, for the past few years that yearly overcoat has become thicker and thicker.

Cautionary Note: - the goose barnacles on the Mid-Atlantic Coast in midsummer, increasingly and probably because of the warmer and warmer water and less water 'turnover' due to changing wind patterns, contain a lot of VERY NASTY microorganisms. The most common BAD actors for both of us are 'vibrio' bacteria - cholera type of bacteria which can be VERY harmful especially if they get into skin cuts where they can sometimes be fatal (flesh eating bacteria!!!) ditto with myco-bacteria which can produce very SEVERE skin rashes. (took me 3+ weeks to recover from a very painful myco-bacteria rash). I no longer dive to scrub my hull during mid to late summer; rather, I now use an adjustable 8 ft. painters pole for my brushes and scrub from a dinghy. The further south one goes the worse the vibrio and mico-bacteria danger ... Florida now has quite a few cases of fatal 'flesh eating bacteria' cases. If you dive and are breaking up barnacles, consider to immediately take a shower using strong 'caustic' type of 'horse-soaps' to lessen the infection potential, etc.
 
Last edited:
Feb 26, 2011
1,129
Achilles SD-130 Alameda, CA
The Micron ULTRA seems to do 'fine' for the first year or so in keeping the slime under control...
Interlux does not make a product called "Micron Ultra". There is Micron CF, Micron CSC, Micron Extra and Micron 66. There is also an Interlux paint simply called Ultra. The Micron products are all ablative paints. Ultra is a hard paint.

Scrubbing 'harshly' with stiff brushes or 'scrubby pads' seems to reactivate the surface especially the anti-slime compounds but not for all that long.
The way to make your paint last as long as possible is to clean it gently. To do this means never letting it get foul to the point where anything but the softest cleaning media need to be used to remove the growth. If you must resort to harsh scrubbing with stiff brushes, you've waited too long to clean the bottom, not to mention you're shortening your anti fouling paint's lifespan. Maybe if you haul for the winter and repaint each spring, this isn't much of a concern. In areas where we boat year 'round and like to get 3+ years out of a bottom job, it is.
 
Feb 14, 2005
4,775
Tayana 37 cutter; I20/M20 SCOWS Worton Creek, MD
You are correct .... Micron EXTRA dame brammage, sorry.

Once Micron EXTRA loses its initial slime prevention ability, you really have to scrub it HARD and remove a wee bit of surface to regain its slime prevention potency. If you scrub gently youll not get much return to slime prevention and youll be back sooner than later to re-scrub; hard scrubbing will extend the time until it again loses it potency/leachability. Thats my experience for the past 4-5 years in variable brackish waters ... from New England all the way down to FL.
Also during that 4-5 years, whenever I return from the 'tropics' and 'back to brackish', Ive found that the anti-slime ability on Micron EXTRA becomes very poor and the apparent 'thickness still remains'.... the only conclusion I can reach is that the anti-slime agent leaches out faster than the paint ablates away.
 
Jun 8, 2004
7,562
-na -NA Anywhere USA
I use to be a sailboat dealer in the Carolinas and put many large boats in. I am not sure if you had your boat hauled but typically if the boat is out for more than 60 days, the anti fouling properties will no longer be good. Not sure if you had your boat hauled or not. Generally, it is best advisable to ask the local marinas and not sure if anyone is left in the area to include Southport with a travel lift. in the Oriental area, Petit Trinidad SR Blue was the preferred and worked very well to include boats that I delivered to Wilmington for what it is worth.
 
Feb 26, 2011
1,129
Achilles SD-130 Alameda, CA
...if the boat is out for more than 60 days, the anti fouling properties will no longer be good.
Typically only true for hard paints. One of the (few) advantages ablatives have over hard paints is their ability to withstand prolonged periods exposed to air.
 
Jun 21, 2009
110
Hunter 27 Sparrows Point
The discussion at our marina concerning bottom paints and barnies, was that last season everyone, no matter whose brand bottom paint you used, was encrusted with barnacles. This year, not so bad. Perhaps more weather related, than paint related.

Sailing more = less growth.

RichH - great point on the bacteria. I cut my finger scraping last year, and took a month to heal.