Need To Know Why to (fully) Understand Bottom Paint Application

Discussion in 'Fiberglass and Composite Boat Building' started by HighFly_27, Nov 13, 2012.

  1. HighFly_27
    Joined: Nov 2012
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    Location: Bonifay, FL 32425

    HighFly_27 HighFly_27

    ref. 1970 Islander 37 (see Pictures of Bottom)

    I'm in the process of Evaulating my I 37 for Repairs & Cost.

    I'm listing them in Order as No# 1 (most important 1st.} and working down the list to the least important, then cosmetic (nice to do but not req'd.)

    The Bottom Paint is in the Top (5) List. However, the Bottom Paint cannot/ or should (what I read) not be applied until no more than two weeks prior to going in the water.

    *** My Question is, " Why ? "

    Does the paint remain soft it's entire life and cannot dry out (boat must be in water) ? I'm a new guy and don't know the reason, just guessing... so please advise me of the Reason ____________ Why; otherwise I'd paint the bottom when the other paint work is done.

    Also, If You Know of a -- Great Bottom Paint, please pass on your Recommendation's i.e. paint name, Type ID, and application tips, etc. .

    Thanks' in Advance,

    Avery
     

    Attached Files:

  2. keysdisease
    Joined: Mar 2006
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    Location: South Florida USA

    keysdisease Senior Member

    Each "type" of bottom paint will have it's own instructions. The two weeks thing you quote is I'm sure correct for a specific paint, but not all.

    You need to answer some questions for a proper referral:

    1st, bottom paint performance is local specific. If you are going to stay in the same area ask the yard which paints work best in that area. Ask the other boats in the yard and any locals you may know. Everyone will have a favorite, but a couple will probably emerge as a consensus.

    Are you going to stay in the water all year / season? Do you need a paint that can "dry out" and remain effective?

    How if at all is cosmetics important? are bright colors important?

    The prop and strut call for special treatment, not the same as the bottom paint typically.

    Are you going to remove all the existing paint? Some paints are not compatible with others and if you plan to go on over existing paint that decision may eliminate some choices.

    Steve:cool:
     
  3. HighFly_27
    Joined: Nov 2012
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    Location: Bonifay, FL 32425

    HighFly_27 HighFly_27

    Not Around the Marina Folks (yet), Boat is 65 m. from Panama City, FL

    I bought the i 37 and had it hauled to my home in Bonifay, FL.

    The boat will not be back in the water until Arpil of 2013. I don't have other sources.. except here and another sailing forum. I'm trying to gather up all the information I can and making a -- Do & $$ Buy List. All (nearly) the repairs will be done by me and my son. I do have a large shop (1000 miles) in PA and transfering the tooling I need to Bonifay.

    So, for the Folks that are locals out of the FL Panhandle.. what is/ was your Bottom Paint Choice ? I do have plan's to sail to the -- Bahamas & further down the Caribbean chain but that's a 2014 idea. I understand that most bottom paints last 2 to 5 years {reading again).

    This boat will be in the water 7 months and then stored at my home for 5 months in 2013. If I'm still around in 2014, then the boat should remain in the water at Panama City, FL from year to year.

    I'd like to hear about a Bottom Paint that does Well when the boat is In or/ Out of the water { takes the sun and sea water too).

    Thanks' again,

    Avery
     
  4. michael pierzga
    Joined: Dec 2008
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    Location: spain

    michael pierzga Senior Member

    I dont no the technical answer. Anti fouling paint is designed to ablate, naturally erode when wet. Long period of dry storage must cause the surface to resist this . I know of no absolute time that anti foul can be left to dry. Normally you anti foul then launch.

    http://www.yachtpaint.com/MPYACMDatasheets/Trilux_33 eng A4 Y 20120702.pdf

    In the technical document for Interntional Trilux 33, a popular antifoul, it states.

    " If Trilux 33 is exposed to drying for any period of time, e.g. over the winter, it must be high pressure fresh water washed before
    being immersed. "

    The bioside is still viable, but drying has trapped it under the surface of the paint. Obviously a pressure wash removes the weathered surface and exposes fresh bioside
     
  5. PAR
    Joined: Nov 2003
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    Location: Eustis, FL

    PAR Yacht Designer/Builder

    There are 4 basic types of bottom paint, each with good and bad things to consider.

    Ablative paints are soft and designed to wear off during use, exposing fresh poison. This stuff is good for boats that come out for storage, because the paint doesn't lose effectiveness when dry. They have water based versions of the ablative now too. The copolymer versions of these seem to work best. The copolymers are harder, but not really a "hard" paint.

    Next or two different types are "hard" paints: epoxy or some derivative and vinyl. These don't rub off like the ablatives, so they can be scrubbed clean when required. The poison leaches out and leaves just the paint, which in time has to have it's build up removed. The vinyls are also hard, but also slick and racers like this stuff. This is the paint they use when they want to burnish or buff the bottom for a really slick surface. This paint will lose it's poison regardless if it's int he water or not.

    Lastly are the thin film paints, which usually is a Teflon kind of surface. They don't hold up as well as the hard paints and generally are used in fresh water.

    As you've been advised, the best choice is what works in your area. This will likely be an ablative.
     
  6. Rebel01
    Joined: Sep 2012
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    Location: Greece

    Rebel01 Junior Member

    I am curious on this as well. The majority of my repairs and work on boats have been fresh water applications. Now, I am living in a total saltwater environment so I am studying up on the best components to use. Many people here in Greece leave their boats on the water year round, so I've seen that they apply a lot of bottom paint.
     
  7. michael pierzga
    Joined: Dec 2008
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    Location: spain

    michael pierzga Senior Member

    You dont need to apply " a lot" of antifoul. You must only use the correct paint for your application and follow the instructions from the manufacturer
     
  8. Rebel01
    Joined: Sep 2012
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    Location: Greece

    Rebel01 Junior Member

    By "a lot" I mean that I see it very often applied to boats as they are constantly in water; therefore, the use is widespread in this part of the globe.

    These are simply my observations as I undertake projects that I intend to use in the sea only.

    I want to ensure that I gain the maximum water resistance and performance possible, while enjoying the boats that I construct...:D
     
  9. Duane P Wetick
    Joined: May 2013
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    Location: Erie, PA

    Duane P Wetick Junior Member

    Copper means death to many micro-organisms, so put your faith (mine does) in bottom paints that have large amounts copper/copper oxides in them...Expensive, Yes!...but effective!

    Cheers, DocWet [Everything has limitations...and I hate limitations.]
     

  10. jehardiman
    Joined: Aug 2004
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    Location: Port Orchard, Washington, USA

    jehardiman Senior Member

    Yes, the paint needs to remain soft or wet its entire life. If it is an ablative, that is so the paint comes off properly, if it is a soft bottom paint it is because the toxin mobility needs to be maintained.

    I'm sorta with keys and Par on this, in that you have to select the proper system for where and how you sail.

    There are two ways paint work, the first is to poision the critters, the second is to prevent them from attaching. To do these two thing you have 4 main choices:

    1) Ablative paints. These work by sloughing off to prevent attachment and generally carries some mild toxins. The problem with ablative paints is that the vessel needs to be moving for them to work, constantly losing the outer layer to prevent attachment and expose fresh toxins. Also is the issue that the paint IS going away, you need to repaint every year, especially if the vessel is high speed which removes the paint faster; and if the boat sits, the waterline action will totally remove all the paint so you need a boottop antifouling also. Generaly, you don't want these types of to dry out or they won't work well.

    2) "Soft" bottom paints. These are multi-year paints for slower vessels or fixed structures. They are generally water porus and work by allowing the toxins to leach out throughout the paint layer, and because of that generally need to be applied right before launching to keep that mobility. Because there is nothing to prevent the attachment of growth, these types of paint are generally avoided because they need massive amounts of toxin to work and bleed that into the surrounding waters.

    3)"Hard" bottom paints. Hard bottom paints are similiar to soft paints in that the primary method of preventing growth is the leaching of toxins, but they are generally designed for higher vessel speed and are multi-year paints that may be dried out. In normal operations, there is enough loss of surface that fresh toxins are exposed, but if left to sit (in air or in water) for awhile, hard bottom paints will need to be scrubbed to expose fresh toxins. Again, these paints are pretty toxic compared to ablative paints.

    4) "Coatings". Coatings may or may not be a paint but are generally non-toxic after applied. They are generally applied to prevent the attachment of growth, not poision it. Primarly for trailer sailers because the boat is not going to be sitting in the water for long periods they can be dried out but will still weather and need to be applied with certian frequency.

    IMHO, and what I found worked well for my sailboat was to strip the hull of all anti-fouling, light abrade and apply a barrier layer, 2 coats of a "hard" high copper paint (Pettit Trinidad red) up to the top of the bootstripe, a blue anti fouling boottop, and below the boottop 3 coats of ablative (Intralux Mircon CSC shark white). The color of the bottom showed when you needed to scrub and when the red undercoat showed at the waterline, it was time to haul and recoat. In your case, given the strut and rudder, I would not consider an ablative paint in that area, but specifically use a hard paint there.
     
    Last edited: May 18, 2013
    1 person likes this.
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