efficient 10m displacement powercat (build thread)

Discussion in 'Boatbuilding' started by groper, Apr 15, 2012.

  1. DennisRB
    Joined: Sep 2004
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    DennisRB Senior Member

    Cheers. I will read up on their website. So looking at my rig you would not be concerned about where the dynex would pass over the spreader tips etc?

    I think there will be a decent weight, and probably cost saving too. The gunboat I saw uses lashings instead of rigging screws. I guess the alloy plates for those would be quite expensive, so you may as well stick with the screws?
     
  2. groper
    Joined: Jun 2011
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    groper Senior Member

    Nup, both our diamonds go through the spreaders end also...

    If you already have rigging screws you can reuse them. If your super paranoid about weight, then you could get rid of them in favour of the colligo deadeye type lashings. I've heard they need to be tensioned under sail however, do the lee side , switch tacks then do the other side...
     
  3. groper
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    groper Senior Member

    Got the boom on;

    [​IMG]
     
  4. groper
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    groper Senior Member

    Ok i have some good news, the work has recommenced on the powercat :D

    The "other cat" is at the point where im not going to do anymore work on it, weve been sailing it and having fun with it these last couple of months, its never finished, but its at the point where we can enjoy it and im not concerning myself with making it perfect. Heres a little vid which shows wheres its at and up and sailing;



    Now back to the original project...

    I molded up using some thin melamine backed MDF and poured in some 70kg/m3 polyurethane foam;

    [​IMG]

    After peeling off the MDF, and giving it a quick hit with the power sander it looked like this;
    [​IMG]

    And then after some longboarding and pouring in the top bit, it looked like this;
    [​IMG]

    Not bad for a half day sunday :D

    Will glass it up this week and also the transoms. Can then think seriously about getting the exterior topcoated :p
     
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  5. jorgepease
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    jorgepease Senior Member

    Hey Groper, beautiful video, wish I was out on the water! Why didn't you just use panels for the front part ... instead of pour foam?
     
  6. whitepointer23

    whitepointer23 Previous Member

    is the foam for bouyancy and to shape the bow or is lt sacrificial to protect the hulls . Looks good.
     
  7. Steve W
    Joined: Jul 2004
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    Steve W Senior Member

    Damn, you've got that Orams looking good Groper, nice job.

    Steve.
     
  8. groper
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    groper Senior Member

    Hey Jorge and Brendan, the bows are shaped from this solid block of foam because it can't be made from flat panels. There is compound curvature in it, even tho it looks pretty much flat in the pics. Most of the compound is down low, where the bilges curve upwards and the hull sides converges. If I could do it again, I would probably bring the topsides together and glue it, and only have to pour the shoe part of the forward hull area...

    Steve, CNO sails along quite nicely, we had her upto 14 kts the other day :)
     
  9. Saqa
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    Saqa Senior Member

    Good to see progress mate, hanging to see how she runs
     
  10. groper
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    groper Senior Member

    Been sanding and fairing... not alot to show for it it seems, but i hope all the hard work pays off when the gloss coat goes on... been doing the inside of the saloon at the same time as the topsides, so theres not much to show other than a heap of surfaces covered in bog and looking like a patchwork quilt...

    Learned alot of lessons during this build, like making sure your panels are sitting fair before glassing them in :mad:

    ive also found its been a bit of a pain/lotsa work with the chine and chamfer panel as it creates an intersect line which is very visible down the side of the topsides, any unfairness creates a wavy line here and must be fixed or it looks poor. Ive got it pretty close now but i dont think i have the patience to get it perfect... The panels naturally pull a little on each bulkhead and a solution to this is worth thinking about...

    [​IMG]
     
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  11. Brian@BNE
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    Brian@BNE Senior Member

    Good to see you still working away. Huge commitment to do what you are doing.
    Maybe you could effectively fair the sheerline further by adding on a rubrail of some kind?
     
  12. SamSam
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    SamSam Senior Member

    If you rounded it more, it would soften the line and be less noticeable. Probably more durable also, I imagine those power cords are leaving some marks/wear right on the intersect line. Even with a well rounded corner, dragging a nasty old power cord or water hose over it will usually leave pretty noticeable scratches.
     
  13. groper
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    groper Senior Member

    Bang on Sam, that's the plan - soften the edge once I'm happy enough with it. For now, it actually helps to find the fair lines by keeping it sharp as it serves a visual que as to where the bumps are which were introduced by pulling the panels around the bulkheads... I should be pretty close to ready for gloss coat in another week or so I hope...
     
  14. waikikin
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    waikikin Senior Member

    Thats correct, the sharp edge is a great indicator, also on flatish surfaces which are harder to fair the use of " bog battens" can help, I used to use an alu extrusion channel 25 x 12 x 3mm, hot melt some simple shelves on, wax and release agent to flat of channel, light resin prime to surface and load the batten and press on. Very good for defining edges and can be boarded in at laps, then bulk screed to known fair indicators, some mist of spray pack helps see where you're at. I like to use hand planes to fairing also, much more satisfaction than the torture board and on spot top ups wont "halo" sanding perimeter.
    Jeff.
     

  15. jorgepease
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    jorgepease Senior Member

    Fairing ... my worst nightmare!! But it looks pretty darn good!!!
     
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