14' Trimaran Restore and Upgrade - Supernova

Discussion in 'Fiberglass and Composite Boat Building' started by Hydromann7, Oct 26, 2015.

  1. Hydromann7
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    Hydromann7 Junior Member

    Hi Any and all,

    Scored a small 14' Supernova Trimaran for $300.00 complete.

    Only missing a few simple fixtures, also needs a few minor hull repairs and and a respray.

    I figured for $300 I can afford to spend another $1k on doing it up to have an awesome little tri.

    So, here's the plan. I'll be doing the rebuilt and upgrades in stages and would value some feedback and recommendations along the way.

    1. Get the thing on the water and see what it does.

    To get to this stage I need to:

    a) Rebuild the rudder, marine ply construction but old and sub bleached with layers de-laminating. Have sanded back and re-glued with epoxy as well as single coated on back 2/3 of blade. Have some left over carbon cloth from a work job and am going to cover foil leading edge to 1/3 with this as it was all chewed up from a reef kiss.

    b) Plug all leaks from same reef kiss and fix one of the main mounting points on the main hull. All cracked and leaking around the locating hole, have ground out all old / rotten glass and washed out. Used marine epoxy with added kevlar chop fibre to thicken into a paste to rebuild the non uniformed area. Repair has come up good but think I'll reinforce with some carbon cloth as well just to be sure.

    c) Make up missing bits and pieces to rig the tri, only a couple of ama clamps missing which I can knock up from 3mm stainless bar. Also need to reattach a couple of pulleys.

    d) Sail the sucker. Have watched some youtube video of this little cat and it seem to sail very nicely. Only issue I could see was that the ama tends to bury if heeled too far.

    2. Ok so once I have sailed it and based on what I have seen on youtube I'm a little concerned about the ama sinking and pitching us. I bought this as a tame option alternative to a 4.4m calypso cat for the family. If I pitch us then there is no chance of upgrading to something like the Corsair Pulse 600 down the track.

    So to fix this I'm looking to modify the ama hulls by extending them about 500mm or 19".

    My plan is to use Knauf foam board which I already have:

    1. Sand back the bow(s), clean and prep for epoxy.

    2. Hulls are hollow fibreglass, i don't want to rely on the epoxy alone for strength and joint so was planning on using through hull dowels to either side with foam board, epoxy and clamping.

    3. Once epoxy has set boards in place I will then reshape the bows the same way I would shape a surfboard by removing excess foam. I am looking to make a slight reverse wave piercing bow with flared canards set at around 3 deg tapering out to 1 deg.

    4. Finish shaping and then lock the whole lot in a skin of epoxy, fibreglass matting and carbon fibre roving for strength.

    A couple of images attached for reference.

    Any suggestions, especially on the bow extensions would be appreciated.

    Thanks

    Hydromann7
     

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  2. Hydromann7
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    Hydromann7 Junior Member

    Onward...

    So I laid up some carbon on the leading edge of the rudder with my 2 younger boys today..

    First attempt at working with epoxy and carbon mat, fairly happy with the results, just need to sand back to a defined edge and finish coat.

    Also laid carbon mat over the hull repair, again happy with result for a novice.

    Have also found that I am missing mast fittings, especially the base clamp... arrrgghhh :mad:.

    Will need to scrounge around the internet and see if anyone has a drawing or images and dimensions so I can make one up.
     

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  3. upchurchmr
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    upchurchmr Senior Member

    There was an Australian who had one before.
    You might search on the forum.
    I believe he is rebuilding a Kraken 25 and building a singlehand TransAtlantic race boat - trimaran.
     
  4. Corley
    Joined: Oct 2009
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    Corley epoxy coated

    Hi, I'd build new floats rather than try and modify the old. They are just too small overall for what you want to achieve. Some simple ply floats would do or repurposed cat hulls. A good donor would be something like a paper tiger cat you want something with more volume but not too much extra weight. The standard rig is small so it wont be super fast with the mods you propose probably slower than it is with the small floats. I quite liked mine when I had it the small floats are pretty safe you just push them under when over pressed and the boat rewards getting your human ballast out to windward. You can also right the boat pretty easily from a capsize with the small floats just pull the centerboard out and lean on it like a dinghy.
     
  5. Hydromann7
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    Hydromann7 Junior Member

    Thanks Upchurchmr,

    Will see if I can track him down.

    Hydromann
     
  6. upchurchmr
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    upchurchmr Senior Member

    Corley is the guy as you can see.
     
  7. Hydromann7
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    Hydromann7 Junior Member

    Hi Corley,

    Thanks for the reply, read your posts on your Supernova, nice to have some input from an experienced user.

    What are you sailing now?

    On the floats I have actually had a rethink...

    Have you seen this http://www.kaptenboatcollar.com/

    It gave me an idea some time back for a mono hull design without ballast, I made a model and it actually worked brilliantly to my surprise.

    What I need in the floats is more buoyancy, this can be achieved only via volume increase. The existing hulls are hollow and as we know air has better buoyancy than foam so an air filled hull is the most buoyant design. However existing design can be enhanced with low density foam, instead just adding length I will also be adding width, it will be similar to the centre hull on a tri where the width increases to increase the buoyancy and provide added lift should the boat bury into a swell.

    I will use the foam along the length of the hull to create what is essentially a rail / chine along the whole length. This will add buoyancy and will also allow me to shape the rail to give hydraulic lift at the bow that increases with immersion.

    So the end result should be that I have the same wetted area for low speed / wind, as wind / heel and speed increase so will the wetted area due to added width but with a lifting effect along the length of the hull.

    I am yet to do the calcs but believe that I will have greater lift from the hydraulic design which will effect the stability more than the added buoyancy.

    Had considered new or use cat hulls but would need to build in my concepts to these anyway. Already have the foam and epoxy on hand as well as carbon fibre rod to make locking dowels, just need to do a bit of gluing, sanding and shaping to existing design and should end up with what I'm after.

    Seems a lot easier to me to use existing design that already fits well rather than make a complete new set of floats.

    Welcome any thoughts or feed back on concepts being considered.

    Greater minds than mine have done better.

    Many thanks,

    Hydromann
     
  8. Hydromann7
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    Hydromann7 Junior Member

    Was thinking along these lines, but shaped much better than drawn :(

    Will try to mimic lines along main hull but with a bit more depth to the flared out profile.

    Hydromann
     

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  9. Hydromann7
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    Hydromann7 Junior Member

    Hull mods

    Kinda like this if you get my rough sketching..
     

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  10. Hydromann7
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    Hydromann7 Junior Member

    Hull mods 2

    Better depiction.

    Dowels = 6mm hollow carbon fibre rod. These will be through hull and sealed with urethane glue or epoxy / kevlar glue paste.

    Foam will be positioned over dowels in un-shaped sections but rough cut to profile wanted. Dowels will be marked and cut slightly short to allow clamping of foam during gluing to fibreglass hull.

    Clamp will be a balsa plate with backing washer screwed into end of hollow dowel. This way if balsa sticks to overflow glue it can be sanded off when final shaping foam.

    Once set the bond between original hull and foam should be very strong. Shaped foam will then be epoxy finished with either carbon or kevlar / fibreglass roving and mat, whatever I can get relatively cheaply.

    Final sanded / under coated and 2 pack polyurethane finished.

    I'm estimating around 80 plus extra litres of floatation per hull along with hydrodynamic benefits. If I get the positioning right then it will not effect the wetted area at low speed and will improve the lift and righting at higher speed and power.

    Hydromann
     

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  11. Hydromann7
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    Hydromann7 Junior Member

    Rudder Sanded out

    We sanded the carbon fibre back yesterday and here is the result.

    Quite happy with the finish, edges blended in nicely with very good adhesion to wood.

    Had actually planned on trimming a clean edge along the carbon fibre when it had gelled but missed the window so had to revert back to sanding.

    Will finish off with fine sand and then spray pack clear polyurethane. Should look better than new.

    Hydromann
     

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  12. Corley
    Joined: Oct 2009
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    Corley epoxy coated

    You may have to look at strengthening the crossbeam structure with the new longer floats as the cantilever will be considerably greater or you could put another crossbeam forward. I never had any problems with my crossbeams but apparently they can break out the fiberglass around their mounting points in the main hull.

    The worst thing about these boats imo is the heavy main hull a new hull constructed with light weight in mind would really boost performance.

    I'm sailing on other club members boats at the moment as none of mine are ready to get wet as yet, last race was on an F82r trimaran.

    Good luck with your project.



     
  13. Hydromann7
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    Hydromann7 Junior Member

    Thanks for the feed back Corley,

    Yeah noted due to past damage to the mounting holes in main hull that they will need strengthening.

    Have fixed the damaged one with an epoxy / kevlar mix and laminated over with carbon fibre cloth, way stronger and only took a few minutes to do.

    Will also be taking some of the loading stress off with eye nuts mounted in main hull forward and aft of mounting locations and then using 200kg rated strap with 316 strap binders to tension either side. This should reduce any movement in this area which would subsequently load up the pin and hole configuration. So instead of just relying on the pin locking plates it will have the straps as well.

    Heavy main hull? Yours must be full of water ;-) I know it's heavy if compared to carbon fibre but for the age and size plus overall weight of the boat it seems ok to me. Probably around 20 to 25kg at the most?

    All up the boat comes in at around 85 to 90 kg which is around the same as my 4.4 cat with foam core hollow hulls.

    Was looking at the Rave V specs at around 150kg and others on a similar size as well and they all seemed around the same or heavier.

    Have gone away from lengthening the hulls to the idea of widening them instead, well maybe 100 - 150mm longer still. Would rather achieve added bow lift hydro-dynamically, also lends itself better to developing foils over winter for it. Have been working on a foil design and calcs for 2 years that does not require complex control systems or adjustments on the fly. In theory they should have little cavitation with minimal chance of ventilation and will ride height adjust across a broad velocity range.

    Still a bit of a pipe dream at the moment as is my ideal sail plan for it.

    First things first though and get what we have wet and working.

    Hydromann
     
  14. Corley
    Joined: Oct 2009
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    Corley epoxy coated

    My main hull was much heavier. It was a solid glass layup and I'd estimate about twice the weight you listed for yours. It wasn't full of water but it was heavy maybe they changed the layup schedule at some point in the production run to take some weight out.
     

  15. Hydromann7
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    Hydromann7 Junior Member

    Wow, not sure what the difference is? Mine is solid glass around 4mm but it doesn't seem that heavy??

    Nowhere near 50kg as my 14 yo son and I can easily lift onto the roof rack.

    I guess they could have skinny'd it up a bit?

    F82r trimaran is a beautiful boat, not seen one in real life but drooling over one for sale in Townsville. That or a similar sized cat would be a dream boat for me if doing coastal cruising.

    For day sailing I'd love the Corsair Pulse 600, still a very expensive boat new for the size of it. A couple that sail out of a club here in WA have just ordered one to replace their little Weta.

    Had a good talk to them about the Weta performance, if I get the improvements I want done and the balance right on the Supernova I think I could give them a good run. Best part is for a fraction of the cost of a Weta. BTW they weigh in at about as much as my Supernova?

    Hydroman
     
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