Is this hull damage or bad bottom paint

Discussion in 'General Maintenance/Repair Questions' started by sbw1, Mar 7, 2018.

  1. sbw1

    sbw1 Well-Known Member

    Oct 10, 2006
    West Michigan
    This is listed in my signature
    This is listed in my signature
    IMG_2848.JPG IMG_2849.JPG IMG_2850.JPG A friend asked me if I had seen a boat for sale that he was interested in possibly owning. The pictures on this thread are of one side below the water line. The rest of the paint looks good with no cracks. This area is about 8 feet long and a foot tall. Any experts out there have experience with this kind of failure and have with a good, informed sense of what happened?
     
    Last edited: Mar 7, 2018
  2. Carpediem44DB

    Carpediem44DB Active Member GOLD Sponsor

    201
    Aug 18, 2015
    Sanfransico Bay area
    2006 44 DB Sedan Bridge Raymarine E120 radar chart plotter GPS autopilot
    cummins QSC 8.3 500 HD
    Definitely would want to remove the bottom paint to the gel coat to make sure the cracking was limited to bottom paint. Also if you can see the inside wall you can see if there is evidence of a repair or delamination.
     
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  3. sbw1

    sbw1 Well-Known Member

    Oct 10, 2006
    West Michigan
    This is listed in my signature
    This is listed in my signature
    Good point about looking under the bottom paint. Inside the boat is a head and galley in that area. So....maybe no easy access. I wonder if there was hull damage because there is a stern thruster on the transom. Suggests a skipper who needed help docking a boat that should be a piece cake to handle. Boat has big props that are set wide apart.
     
  4. fwebster

    fwebster Well-Known Member TECHNICAL Contributor PLATINUM Sponsor

    Oct 6, 2006
    Middle Tennessee ; Panama City Beach, FL
    1996 450DA
    3116 Caterpillars
    We occasionally see that "cracking". In every case it has been the result of "cosmetic bottom jobs" done on the cheap where a quick (meaning minimal sanding) additional coat of bottom paint is rolled over several previous coats of paint. The water line looks great but it is a thin coat of antifouling which wears out or gets covered by slime or algae very quickly. THe rate of expansion for bottom paint is significantly different than FRP structures, so after a winter with a lot go temperature changes, the cracking appears.

    I'm not a lot worried about there being problems under the paint in the gelcoat or FRP because that type of cracking in gelcoat would only be associated with physical damage and an improper repair which should be obvious to a decent surveyor. Besides, to fix the cracking paint, you will need to remove almost all of it by sand or soda blasting and you can see exactly what is underneath.
     
  5. sbw1

    sbw1 Well-Known Member

    Oct 10, 2006
    West Michigan
    This is listed in my signature
    This is listed in my signature
    The bottom paint looks somewhat fresh. The boat is on a trailer and has been outside for awhile in freezing temps and has also seen some sunny warm days in the past month. Just showed up, so we don't know where it spent the winter. Paint may have failed recently.
     
  6. Lazy Daze

    Lazy Daze Well-Known Member TECHNICAL Contributor GOLD Sponsor

    Apr 21, 2009
    PA
    Various
    Various
    I don't see in anything in those pictures that worries me from structural standpoint in regards to the actual boat. There are no obvious points of impact in those cracks. I agree with Frank - it looks like a quick coat of bottom paint was put on for the sale and it didn't play well with the underlying gelcoat. And that area may have spent time in the sun right away and caused (at least hastened) that cracking. But it appears purely cosmetic to me.
     
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  7. Brite Idea

    Brite Idea Member

    118
    Nov 5, 2011
    Long Island, New York
    270 Sundancer 2000
    twin 4.3 TBI Merecrusier Alpha Gen II counter rotating drives
    I've seen that happen when cheap hard bottom paint is applied in cold weather. The bad part is that it's going to be under whatever you paint the boat next with. I doubt there's anything wrong with the boat just improperly applied paint.
     

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