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36 Convertible Bottom Job

Discussion in 'Luhrs Yacht' started by Josh Keeran, Apr 21, 2020.

  1. Josh Keeran

    Josh Keeran Member

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    Last fall when I pulled the boat for the season I planned on completely redoing the bottom. I had it blasted to gel coat but weather was not on my side and had to let it sit all winter. Finally had a window of opportunity to finish the job.

    there were a few patches of blisters that had to be filled with Interlux watertight. Based on their locations and that they were in consistent patches I assume they were just flaws from the factory.

    next was multiple coats of Interlux 2000 barrier coat. I switched colors from grey to white between coats. Interestingly, the white was much more difficult to work with and did not spread nearly as far as the grey. Had to use almost twice the white per coat compared to grey.

    finished it off with 320 grit sand paper and spraying 4-5 coats of Interlux VC-17. Hindsight I would have done one more coat of barrier coat and sanded more first. Turned out smooth but I would have liked a bit smoother.

    A ton of work but in the end very happy with the final product. This is my third time doing this project but bigger boat everytime. I can see why the yards charge so much, especially the older I get!

    Attached Files:

  2. mapism

    mapism Senior Member

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    Well, RESPECT is the word that springs to mind!
    Having seen what it takes to get jobs like this done properly, tackling it as a DIY project is indeed remarkable.
    Very, very well done.

    Ref. the blisters patches, let me guess: were they mostly along longitudinal lines, parallel to the spray rails and/or on the rails themselves?
    That's what you typically find on many traditionally laminated hulls, and normally is rather superficial, affecting only the gelcoat.
    If that is the case, after your treatment, I'm sure it will not be a concern anymore in the future.

    Ref. the VC-17, did you already try it in the past? And in fresh or salt water?
    In any case, I'd be interested to hear your view about its effectiveness and durability, because I read mixed reports about it.

    PS: lovely boat, BTW! :)
  3. chesapeake46

    chesapeake46 Senior Member

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    Amen brother, nice job.
    Also: appreciate the pictures.
  4. Josh Keeran

    Josh Keeran Member

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    thanks a ton!

    As far as the blisters, yes just as you stated Mostly along longitudinal lines and along parallel to spray rales/rakes. After seeing the pattern I assumed the same that they are not a major concern.

    the boat is a fresh water Lake Michigan boat. I had VC-17 on my 29 Tiara for ten years and had great results. Provides a very smooth slick surface for the boat to ride on. In our area it is used on all the racing sail boats. Also the growth is removed very easily. I have not had my Luhrs out since putting in the water but I’m anxious! I gained 2 knots cruising speed when I completed the same process on my Tiara
  5. mapism

    mapism Senior Member

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    Wow, 2 kts on a not so fast boat (low 30s, I suppose?) is a helluva improvement!
    Do you possibly have any reliable indications from someone who tried the stuff also on salt water boats?
    Here in the Med, that type of antifouling paint is almost unheard of.

    Ref. the blisters, yep, that pattern definitely comes from the original hull moulding.
    A bit tricky to explain, but it's mostly driven by the sequence and timing of the manual stratification by roller.
    Rather common in traditional moulding, and has nothing to see with what is normally called osmosis.
    I mean, it's still possible to find hulls with this kind of blister pattern AND also "deeper" osmosis with resin release, but they are different things, with different reasons.
    The former being much less worrying than the latter of course, which in the worst case can even create structural delamination.
  6. Josh Keeran

    Josh Keeran Member

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    I am not too sure about VC-17 in salt water environments. It is very widely used in the Great Lakes area without issues. The only reference I really seen in salt water is the “Carolina smile” painting technique where an anti fouling paint is used around the water line and a VC paint is used on the running surfaces.

    http://www.yachtpaint.com/LiteratureCentre/ATE_CarolinaCoat.pdf
  7. cleanslate

    cleanslate Senior Member

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    Very nice job !
    I can just imagine how much time it took and I feel your pain sitting here writing this. Lol
    How did you spray the paint on are you in the painting business yourself with the fancy spray guns or was it just an electric spraygun?
    If you don’t mind me asking how much was it for the sandblast work?
  8. mapism

    mapism Senior Member

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    Thanks for the "Carolina smile" pointer, I never heard of that type of application.

    Interesting to see M66 suggested along the areas more prone to fouling, because that's a rather popular product also in the Med, and widely considered very effective.
    On the other hand, there are mixed views on any teflon-added paints like the VC, for three reasons:
    Firstly, they rely on being slippery enough that any growth is quickly polished away with the boat movement. But if and when the boat is not moved for long enough to let barnacles stick on the surface, it's game over for self-polishing, and it's necessary to scrub or powerwash the hull again.
    Secondly, as I understand, while it can also be applied by roller, it takes airless spray for the best results.
    Last but not least, if you should decide to revert to another a/foul, it's necessary to remove it completely, which is a pretty tough job, with any epoxy.

    Anyway, I guess it can be a good solution for boats which are either moving regularly, or are often pulled out of the water.
  9. cleanslate

    cleanslate Senior Member

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    I always thought it was that brown cedar tree water stain on the lower bow from the I.C.W. section of the Carolinas. Alligator / Pungo -fungo canal stain and Coinjock skank stains.:rolleyes:
    Know I know. thank you.