30' cruising catamaran repair log

Discussion in 'Boatbuilding' started by jdory, Aug 7, 2015.

  1. jdory
    Joined: Aug 2015
    Posts: 114
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    Location: Nome, Alaska

    jdory Senior Member

    Somebody asked how much this weighed and how it compared to a store bought aluminum boom. I don't know what the other booms weigh of equal size (13') and strength - possible about the same or maybe even a bit lighter, but this will be ok. At this point, I weighed it with the sheave boxes (minus sheaves) and it was at 46 lbs. With the rest of the glass and carbon and whatnot, it'll be over 50 lbs. I'll weigh it again when all finished, perhaps.

    Here's a few pictures of getting the last of the full length carbon fiber and fiberglass on the boom, using a vacuum bag. Was a bit worried about vacuum bagging the whole boom in a bag as I wondered if I could crush it. I tested it first with a leaky bag - not full vacuum, and slowly closed up the leaks. It seems pretty stout, so went with it. I just use a shop vac so not sure I have the strongest vacuum anyway.

    But it still laid down the fiber pretty good and sucked some excess epoxy out of the mix. I did have a few wrinkles in the carbon - not sure what I do wrong there as it was nice and smooth when I put down the peel ply. Must have been as the bag sucked up, it pulled a bit on the carbon as it sough equilibrium.
     

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  2. jdory
    Joined: Aug 2015
    Posts: 114
    Likes: 2, Points: 18, Legacy Rep: 10
    Location: Nome, Alaska

    jdory Senior Member

    And here I am getting ready to set the sheave boxes. I put some Saranwrap (plastic kitchen wrap) around the base, then added some thickened epoxy under the boxes and pushed them into place, hoping the epoxy will squeeze out and create a nice little socket for the bases. The boxes will be removeable (I hope) so I want a good base that the boxes will be screwed through - the epoxy should help resist some shear force on the screws. The boxes will bear against the boom where they exit, to help resist force there, and the sheaves will be pinned through the sides of the boom to further help hold them in place. I'll reinforce the sides of the boom a bit where the tops of boxes bear against, and where the pin exits the sides.
     

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  3. jdory
    Joined: Aug 2015
    Posts: 114
    Likes: 2, Points: 18, Legacy Rep: 10
    Location: Nome, Alaska

    jdory Senior Member

    Fairing and rails for the boom. Using pvc conduit for rails, to be wrapped in fiberglass and insert dowels into them for stiffness. Had to make my own dowels as store-bought ones were too small in diameter.
     

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  4. Catamaran Dan
    Joined: Apr 2009
    Posts: 6
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    Location: Michigan

    Catamaran Dan Junior Member

    Got your post on the trailer. The trailer started as a equipment and log hauling unit. When I purchased the boat the yard had a pile of steel square tube from 4 x 6 to 8 x 8. I will need to look through for some pictures but basically I extended the hitch, set a cross beam of square tube at the front and back then used a smaller tube that slid inside the trailer mounted tubes and can extend them to catch the hulls. Only sits on 4 spots on the trailer. The pads are about 3 ft. long. Front with rollers back is just wood planks. I will look for some picks. Before I bought my boat I had visited Kurt as my brother lives in the Seattle area.
     
  5. jdory
    Joined: Aug 2015
    Posts: 114
    Likes: 2, Points: 18, Legacy Rep: 10
    Location: Nome, Alaska

    jdory Senior Member

    thanks C. Dan!
     
  6. Catamaran Dan
    Joined: Apr 2009
    Posts: 6
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    Location: Michigan

    Catamaran Dan Junior Member

    So looked through my picks and have nothing on the trailer. Will be putting the boat in the water in a month or so and will take some picks then. If I remember. Don't do that so well anymore. Looked back through your earlier pages and see you were working steering. I made quadrants for the rudder posts and set sheaves purchased from McMaster Carr I think and those go to the wheel with a piece of chain to the wire. Stainless 1/8" wire and it has been flawless for about 10 years now. See picks. Very smooth and all the power needed but can get a bit stiff in heavy seas. Attached a pick of why I bought my boat pretty cheap. Hand crank winch on an I beam lift for small boats. Sign on the lift says 9000 lbs. At the time the boat weighed about 16,000. Supports parted and it all came down on the boat with the guys daughter standing on one of the front nets. You just cannot fix stupid. After seeing the pick of the wreck and what little damage was done I did not have many worries about strength. Boat dropped about 3 ft. and landed on a steel sea wall and a steel dock. Just a big scrape on the bottom at one of the dagger-board openings needed some work. The gunnel on one side had to be repaired as well. Bigger issue was rotted bottom bridge-deck sheeting. Replaced about 40 sq. ft. Anyway keep the faith getting there is half the fun.
     

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  7. jdory
    Joined: Aug 2015
    Posts: 114
    Likes: 2, Points: 18, Legacy Rep: 10
    Location: Nome, Alaska

    jdory Senior Member

    Building my quadrant as we speak, so to speak. Thanks for sharing those pics.. nice to see how others do things, which is hard to do up here in my sailboat desert.
     

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