Bottom Paint Question

[BandB]

I'm going to clarify a number of erroneous assumptions being put forth in this thread:

1.- Regardless of how frequently your diver cleans your boat bottom, the media he uses to do it is 100% predicated upon the fouling he finds when he gets there. A statement like, "If you have your boat dived monthly, the diver should never use a scrub pad" is patently ridiculous. If your paint has outlived its useful lifespan and is fouling badly , that fouling may very well require an abrasive pad to remove it, regardless of paint type or cleaning frequency.

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I'll repeat, your diver should never scrape. You should not let your paint outlive it's useful lifespan and reach the stage of fouling badly. That is patently ridiculous. If you clean the bottom often enough and repaint often enough then scraping will not be required. To base your objection on fouling after the paint is gone is no different than arguing on a bottom that has no bottom paint. It doesn't reflect best practices. We've never had scraping on any of our bottoms and we currently either own or are managing 7 boats.

 

[fstbttms]

I'll repeat, your diver should never scrape. You should not let your paint outlive it's useful lifespan and reach the stage of fouling badly. That is patently ridiculous. If you clean the bottom often enough and repaint often enough then scraping will not be required. To base your objection on fouling after the paint is gone is no different than arguing on a bottom that has no bottom paint. It doesn't reflect best practices. We've never had scraping on any of our bottoms and we currently either own or are managing 7 boats.

You completely missed the point. I didn't say "cleaning after the paint is gone." I said after the paint has expended its biocide. If you think that every boat owner hauls for paint as soon as his diver indicates the boat needs it, you are sadly mistaken. And it's a misconception to think that a hull cleaner uses whatever he wants to clean your boat bottom. He uses what is necessary to remove the fouling growth that you have allowed to accumulate there.

BTW- I am in daily contact with many Florida hull divers and what they tell me is that scraping (which they call "blading") is SOP for hull cleaning there. But maybe yours is special. :lol:

 

[foggysail]

I'm going to clarify a number of erroneous assumptions being put forth in this thread:

1.- Regardless of how frequently your diver cleans your boat bottom, the media he uses to do it is 100% predicated upon the fouling he finds when he gets there. A statement like, "If you have your boat dived monthly, the diver should never use a scrub pad" is patently ridiculous. If your paint has outlived its useful lifespan and is fouling badly , that fouling may very well require an abrasive pad to remove it, regardless of paint type or cleaning frequency.

2.- All anti fouling paint manufacturers (and this hull diver) recommend a minimum of two coats of paint with three at the high wear areas like the waterline and leading/trailing edges of appendages. Boatyards are notorious for recommending just one coat because they know that with less biocide on the hull, the sooner you will need to haul for new paint.

3.- Anti fouling paints work (ablatives included) at least in part by leaching their biocide into the water very near the boat hull. For this to happen, water must penetrate the paint's surface. Yes, it is possible to apply so much paint that the water cannot penetrate the paint matrix deeply enough to free all of the biocide and in this case, the additional paint is useless. But two or three coats of any anti fouling paint are not enough to cause this. And again, when you apply a single coat as opposed to two or three, you have reduced the total amount of biocide available to retard fouling growth on your hull. And since the biocide is released continuously and at a predetermined rate, less paint means the available biocide is depleted earlier, necessitating more frequent haulouts.

Gees! Now I wonder why ''all anti fouling paint manufacturers recommend a minimum of two coats of paint.........."

If my business was manufacturing anti fouling paint.....or was a dealer selling the stuff, why heck, I would HIGHLY recommend a minimum of FOUR or even FIVE coats.

The amount of paint IMHO should be determined by how long the boat being painted is in the water along with what water area the boat is used. And I guess the planned number of bottom cleaning events expected could also be a consideration.

Just adding layer upon layer of paint for seasonal use here in Massachusetts' waters is not only money wasted, it will also result in heavy thicknesses of old paint that could require bottom stripping. Around here bottom stripping costs big bucks.

 

[fstbttms]

Well, you make a valid point but the fact is that the great majority of boats in this country that use anti fouling paint do not have short sailing seasons. And it is also a fact that boats that do live in the water 24/7/365 typically get good performance from their anti fouling paint for about twice as long with two coats as opposed to one coat.

 

[psneeld]

I have a bit of experience in the bottom painting and ablative use business too.


Besdes an assistance towboat fleet it includes responsibility for USCG boats when the Commandant was real anti- toxicity and wanted to explore "options" other than chemical antifouling.


I have been using ablative/self polishing/etc paints since the 1980's on my own personal boats.


My recommendation on how many coats to use is based on your usage of the ablative paint.


Some years for me...1 coat except for high wear areas is all that came off......so the next haul, 1 coat went on...other years it seemed that more came off so 2 coats went on. I have never seen a need for 3 coats even on assistance towboats that run and run and run.



Also none of my boats or the assistance towboats or the USCG boats ever saw a diver. I understand their need for most recreational boaters, so factor that into your operation too.

 

[Delfin]

So, here's another question. When the ablative paint has become thin, opinions please on whether to apply one coat or two coats of paint. We boat on the east coast, primarily on the Chesapeake.

Two, of different colors so you can see when it is time to recoat.

 

[Chrisjs]

I guess most of us use ablatives, but also most of us travel slowly at trawler speed. Since this is a (fast) planing boat, is there a case to be made for a hard (non ablative) bottom paint??

 

[rslifkin]

I guess most of us use ablatives, but also most of us travel slowly at trawler speed. Since this is a (fast) planing boat, is there a case to be made for a hard (non ablative) bottom paint??

Depends on how fast he cruises. And some ablatives ablate faster than others. I haven't had issues with excessively fast wear with Micron CSC or Micron Extra on my boat that cruises at 17 - 18 kts. Stuff targeted at keeping sailboats clean will ablate more easily, I'd think, so may not be a good choice on a faster boat.

 

[BandB]

You completely missed the point. I didn't say "cleaning after the paint is gone." I said after the paint has expended its biocide. If you think that every boat owner hauls for paint as soon as his diver indicates the boat needs it, you are sadly mistaken. And it's a misconception to think that a hull cleaner uses whatever he wants to clean your boat bottom. He uses what is necessary to remove the fouling growth that you have allowed to accumulate there.

BTW- I am in daily contact with many Florida hull divers and what they tell me is that scraping (which they call "blading") is SOP for hull cleaning there. But maybe yours is special. :lol:

No, I don't think everyone does haul when the bottom paint is shot. I just think they should, and, if they did, there would be no cause for scraping. We do not allow scraping ever. I have a good friend who manages 10 boats and he doesn't allow scraping ever. We both use bottom cleaners who fully understand.

Yes, scraping is standard for all those who don't get cleaning frequently enough and don't haul with the bottom paint is shot. I didn't miss your point. I used the word "should".

 

[Mark P]

Okay, since I started this thread, let me add some more info. Just heard from the Marina, it does need bottom recoat. $2600, including outdrive. Sounds reasonable - about $100/ft of painted surface, includnig the outdrive. I will send pictures when all done. Some thoughts, please: On this 28ft Sea Ray SLX 280, I rarely go over 20mph, although it can go quite a bit faster - is this fast enough to knock of barnacles that have attached? I am not talking slime, these things are attached. I think my problem is that I don't use it enough and it sits at times for 3 weeks, sometimes a month, before i can get back to her and run her out for a while.
Question for FSTBTTMS or Divers on TF: What should I tell my diver to use on the bottom in terms of scrubbing? Or am I just toast because the waters on Hilton Head are so warm the growth will come and attach unless I run it often?

 

[BandB]

Okay, since I started this thread, let me add some more info. Just heard from the Marina, it does need bottom recoat. $2600, including outdrive. Sounds reasonable - about $100/ft of painted surface, includnig the outdrive. I will send pictures when all done. Some thoughts, please: On this 28ft Sea Ray SLX 280, I rarely go over 20mph, although it can go quite a bit faster - is this fast enough to knock of barnacles that have attached? I am not talking slime, these things are attached. I think my problem is that I don't use it enough and it sits at times for 3 weeks, sometimes a month, before i can get back to her and run her out for a while.
Question for FSTBTTMS or Divers on TF: What should I tell my diver to use on the bottom in terms of scrubbing? Or am I just toast because the waters on Hilton Head are so warm the growth will come and attach unless I run it often?

What paint are you using?

 

[Mako]

Chrisjs "I guess most of us use ablatives, but also most of us travel slowly at trawler speed. Since this is a (fast) planing boat, is there a case to be made for a hard (non ablative) bottom paint??"

Depends on how fast he cruises. And some ablatives ablate faster than others. I haven't had issues with excessively fast wear with Micron CSC or Micron Extra on my boat that cruises at 17 - 18 kts. Stuff targeted at keeping sailboats clean will ablate more easily, I'd think, so may not be a good choice on a faster boat.

Good question and I'd like to know more also. I was under the impression that ablatives are better for higher speed boats in order to ensure the peeling of layers (at the micro-level of course), thus exposing new biocides. And that hard coatings are better for slow, displacement speed boats which will never reach those speeds, and which can be scrubbed a bit more.

I switched to ablative on one of my past boats and after a season did notice more wear at the waterline than below.

 

[fstbttms]

On this 28ft Sea Ray SLX 280, I rarely go over 20mph, although it can go quite a bit faster - is this fast enough to knock of barnacles that have attached?

Not a chance.

Question for FSTBTTMS or Divers on TF: What should I tell my diver to use on the bottom in terms of scrubbing?

Please don't use the information you garnered from a group of people who do not clean boat bottoms to try to educate your diver about his or her profession. If you have a halfway experienced hull cleaner, he/she is going to know what cleaning media will be necessary to remove the fouling on your hull. And again, what they use is completely dependent upon how foul you let your boat bottom get between cleanings. Know also that relatively frequent, gentle cleanings will add significant time to the lifespan of your expensive anti fouling paint as opposed to less frequent, more abrasive cleanings.

 

[BandB]

Know also that relatively frequent, gentle cleanings will add significant time to the lifespan of your expensive anti fouling paint as opposed to less frequent, more abrasive cleanings.

Major point. For us, it's every three weeks during half the year, every four the rest of the year but the period of every four has gotten shorter, fewer months. Our diver is charged with the task of not letting it get to the point of requiring abrasive cleaning and does an excellent job. They check conditions starting at two weeks and occasionally clean at two weeks. However, we're averaging 2 1/2 years on bottom paint.

Now, for all you bottom cleaners, I'd toss out to owners, you can make their jobs easier with more frequent cleanings. Yes, it will cost more but they'll give you price breaks and it will pay off in other ways, including fuel and bottom painting. In some areas, bottom cleaning isn't as much an issue but in other areas it may be the most important maintenance item you have. Our bottom cleaner checked once this summer after two weeks and told our engineer they'd be out to clean the following day based on what he saw.

 

[boatpoker]

Hard to tell from the photo due to what appears to be marine growth however .... there should be a 1.5" unpainted border around your transom assembly.
This required by drive manufacturers and will be in your manual.

The reason, many (most) bottom paints have some metal component such as carbon, titanium dioxide or cuprous oxide that can cause a galvanic reaction with the aluminum of your drive if in contact and enhance corrosion of the aluminum.

 

[larman]

What is the best method for removing barnacles, just pulled boat and it is loaded.

 

[boatpoker]

What is the best method for removing barnacles, just pulled boat and it is loaded.

You know they are edible .... right ?

 

[foggysail]

Okay, since I started this thread, let me add some more info. Just heard from the Marina, it does need bottom recoat. $2600, including outdrive. Sounds reasonable - about $100/ft of painted surface, includnig the outdrive. I will send pictures when all done. Some thoughts, please: On this 28ft Sea Ray SLX 280, I rarely go over 20mph, although it can go quite a bit faster - is this fast enough to knock of barnacles that have attached?

That price estimate seems high for a 28' boat. Does the job include old paint removal,adding a barrier coat plus bottom paint? Must be more to the estimate than scrapping old growth and bottom painting. And much of old growth usually succumbs to a high pressure water sprayer. My sprayer (4000psi @3gal/min) started taking the paint off my van until I stopped spraying.

 

[Kawini]

Is there anybody out there in the PNW who keeps their boat in the water year-round who cares to chime in with how often they get their bottom cleaned? I'm imagining that it's less frequent than in Florida. But, like I say, I'm just imagining.

Assume that the bottom is in good shape and newly painted.

 

[larman]

You know they are edible .... right ?

I also hear that you use them on your hemroids., right?