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Nacra 5.2 hull repair  Bottom

  • Hi all,

    Greetings from Canada. Me and my friends (we are new to sailing) just purchasrd a Nacra 5.2 and noticed there is a crack at the hull. We would like to get some advices as to the correct steps of repairing the hull.

    We have no previous experience with fiberglass.

    We have no access to the back of the hole as it was covered by the backboard.

    Step 1) remove the fiberglass for the loosen piece and smoothen the edges
    Step 2) sand off the gel coat and making a 1:12 downward edge for the surrounding area using a 60 girt sandpaper
    Step 3) using the 3M Bondo fiberglass resin repair kit, cut the fiberglass to the size of the hole plus 1-2 inches and another 2 layers with slightly smaller area
    Step 4) missing the resin and the hardener and soak the previously cut fiberglass
    Step 5) put the fiberglass onto the damaged hole
    Step 6) let it dry
    Step 7 )sand off the patched area to make it smooth

    Do we need to apply gelcoat after?

    Are we missing any steps to the above?

    Any advices you can provided will be greatly appreciated.
    The boat
    Location of the crack

    The crack
  • Sorry for creating multiple posts. When I posted, it shows network time out and I thought it didn't went through.

    For the image, please use the below link.
    The boat:
    The location of the crack:
    The crack:
  • Hi,
    Check out my hull repair as featured on Joyrider TV.

    I have some pictures on the forum here as well.

    Bryan in Poplar Grove, IL
    Supercat 17, unknown year. Future project
    Hobie 16, 1977 - died a spectacular death https://youtu.be/Y7O22bp2MVA
    Hobie 16, 1978 - current boat
  • This is how I have repaired similar damages in A-cat hulls and a 5.5. It can save you a lot of finishing work on the outside. Can be done on your 5.2 as you have good access to the inside of the hull. Go for epoxy even if the boat is GRP.

    Cut the edges of the damage both in the hull and the pushed in “flap”, leaving the flap attached to the hull.

    Work from the inside after carefull cleaning and sanding the area of” inside of the hull and backside of the “flap” and add a well overlapping piece of 1mm G10 sheet using thickened epoxy(ex. West G/Flex 655).

    Add pressure from the inside to make the G10 bend to the hull inside and the flap being flush with the hull on the outside and also let the epoxy fill the gap between edge cut hull and “flap”. If the flap wants to flip outwards add some brown tape to keep it in place.

    Sand down the gelcoat in the damaged area, add new and finish off.

    Don´t know much about Bondo as it isn´t available in Sweden, but it is probably OK.


    Frankencat 5.5/F18
    Soon Frankencat 5.8/F20
  • Check the Hobie Hotline article for “Blind hole repairs.”


  • DogboyCheck the Hobie Hotline article for “Blind hole repairs.”



    Great info~!
  • Thank you all for your kind suggestions. Hopefully we will start the repair this or next weekend. Will definitely post pictures of progess in the comments.
  • I would not use 3M Bondo. It absorbs water, & cures to an ugly color. It’s made for bodywork on cars.
    I used it, once,on an old Bombardier Invitation. Stick with one of the products made for marine use, West system or other.

    Hobie 18 Magnum
    Dart 15
    Mystere 6.0XL Sold Was a handful solo
    Nacra 5.7
    Nacra 5.0
    Bombardier Invitation (Now officially DEAD)
    Various other Dock cluttering WaterCrap
  • I missed the bondo. I think bluesquirrel is talking about bondo brand resin and cloth. I'm pretty sure it's polyester and not epoxy resin, so it may eat foam core. Not good. I'd recommend getting real epoxy resin. Much better quality. We used a lot of bondo resin on an old hovercraft project and I'm not impressed with it. As a teenager, I'd used a lot of it for automotive work but didn't know better.

    Bondo body filler is a different animal, and you should avoid it at all costs.

    Bryan in Poplar Grove, IL
    Supercat 17, unknown year. Future project
    Hobie 16, 1977 - died a spectacular death https://youtu.be/Y7O22bp2MVA
    Hobie 16, 1978 - current boat
  • Ouch! Good to know! Let me try to see if I am still able to refund it and shop for west system epoxy resin!.

    Thanks guys!
  • Hi all,

    thank you for all the help. We did patched the crack and had our first sail on the lake!

    Unfortunately, we were too focus on the fixing and did not take many pictures.

    Thank you Dogboy for the article, we did follow the instruction to insert the back support.

    Also thanks revintage for the steps of the patch job. We did keep the flap and tried to fill the gap with epoxy.

    Some of the image for the patch work:

    the epoxy we use this time
    working on it:
    finished work
    getting the boat on the water
  • The image you posted as finish work looks a bit rough. Did you do some sanding, fairing and finishing of this?

    NACRA 5.7 (1984 Sail 181)
  • Yes, we are planning to sand down the area and apply gelcoat hopefully this or next weekend.
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