How to mount rowing rigger on trimaran?

Discussion in 'Boat Design' started by ckelly, Feb 22, 2017.

  1. ckelly
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    ckelly New Member

    We are planning to do the Race to Alaska 2017 and have purchased a set of rowing riggers to mount to the amas of a Corsair 28CR. The rowing riggers have strong suction cups so we thought, initially, we would be able to mount directly to the amas. We'd planned to glue smooth plastic disks under the 'feet' to ensure suction was maintained. However, the amas are curved and the feet don't swivel or extend.

    I'm curious if anyone has thoughts on whether or not a platform might be our best route or trying to modify the feet. If we build a platform of sorts we'd been told that starboard or marine plywood might work. Note that we do not want to drill any holes in the amas if we can help it.

    Photos of riggers, ama and paddles below. All suggestions welcomed and entertained. Thanks in advance!

    Corsair 28 ama.jpg

    Rowing rigger close up.jpg
     
  2. Richard Woods
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    Richard Woods Woods Designs

    I'd check with Wayne Gorrie. Having said that he was I think the only competitive team still using oars. Everyone else change to the more efficient leg powered props.

    The direct drive system Alec Mackenzie designed for us on Bad Kitty worked really well. Even I could pedal it at 2.5 knots by myself

    Richard Woods of Woods Designs

    www.sailingcatamarans.com
     
  3. ckelly
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    ckelly New Member

    Very interesting, Richard. We mulled the pedal power vs rowers and thought sliding seats would be faster unless we had a big enough prop but, ultimately, landed on what we "thought" would be an easy install of the rowers. ;)

    Can you PM me the contact information for the gentleman who helped w/pedal power installation on Bad Kitty? Really appreciate the help.
     
  4. Richard Woods
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    Richard Woods Woods Designs

  5. ckelly
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    ckelly New Member

    Terrific - will do. Thanks again!
     
  6. rower mike
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    rower mike Junior Member

    rowing wise...

    if you are willing to epoxy mounting points / wood blocks to the side of the main hull.... and the side or top of the ama's that would give you something to drop a cross piece between the two onto .... and you could screw the crossbeams into those .... instead of the amas/ main hull....

    the feet of the rowing slide system you show in the picture could go on two such cross pieces....ditch the suction cups and bolt that seat rail system to them or go some kind of mortise and tenon arrangement for disassembly / easier storage. as you'll likely want to sail as much as possible and likely need the tramp space for that....

    though that system in your pic of the rails and seat does not really show anything to push against with your feet when rowing... that's the part that has to take all the force. but you could bolt something across the end of the rails shown in the Pic if you had too for that...

    but then ..... there is the whole issue of how to mount a rigid pivot point for the oar itself to work against... and that again has to take a pretty big load force wise... so same thing... another cross beam like the first but this one has to be super secure and rigid.... but laminate a curve into one end
    You need a flat straight part that'll pass under the rails of the sliding seat system and act as a crossbeam.... then have the end of it curve up to a base/platform to mount the pivot point/oar pin on.. but well out from the side of that seat and rail system in the Pic....so you can get enough leverage to row efficiently

    you need to get the geometry/ heights /biomechanics right though...
    too high or too low and you can't row worth a &^(^( !!!

    from your picture it looks like you've got the shorter sculling oars
    (ie for when each person rows with two oars... one in each hand.. one on each side of the boat)

    suggest you check out "sweep" oars .. they are just a couple ft longer and meant to be rowed one oar / person ie give you more leverage and have more blade area ... so they can take full force one person with less slip thru the water. versus each sculling oar be designed to take half the force.
    I would think that sweep rowing would be better suited to your Tri
    and the extra oar length might make the rowing geometry a little easier to work out... but of course.... now you need two full set ups and two people rowing together to stay straight. though if you have a crew of four .... you may even want to try four people rowing...

    that all I got... for a Q & dirty system off the top of my head...
     

  7. ckelly
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    ckelly New Member

    Thanks, Rower Mike. That makes perfect sense and aligns with systems we've seen - since I posted this - on an F27. Of course, now we're hearing also that we should consider pedal power instead - so, we're trying to think through what that might require, as well.

    Really appreciate the thoughtful response!
     
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