New low-cost "hardware store" racing class; input on proposed rules

Discussion in 'Sailboats' started by Petros, Mar 19, 2012.

  1. Segler
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    Segler Junior Member

    Thanks. I will try that.
     
  2. SukiSolo
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    SukiSolo Senior Member

    Well done, you got her on the water, no mean feat.

    The centreline buoyancy is OK, but you have made it a bit too wide IMHO, it works on some classes and is a way of stopping a boat floating too high when capsized. Behind the case it is a bit too obtrusive, to movement, but it does need to support a bit the top end of the transom rudder fitting - go refigure (as you say your side of the Pond)!

    It also looks like you have too much rocker, the bow is well clear of the water in the shots. This does not help directional stability, especially on a windy run! so contributes a little to 'nervousness' in the handling. Quite narrow overall beam too, but that is personal, and I'm used to things well over 2 meters wide at that length (and I know your beam limits).

    Good work, especially at the price level, all the boats you build are a learning experience. The key seems to be to note all the subtle differences of every hull and try to find a good compromise with the best features. At least that has been a good guide for me, a spreadsheet does not tell the whole story...;)

    Keep up the exploration!
     
  3. Segler
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    Segler Junior Member

    Thank you for your reply.

    It may not be too much "rocker". I think it's more a case of a light crew and a heavy skipper, sitting too far aft in a very light boat. Fully rigged weight is only 215 lb, which is about what I weigh (fully rigged).
     

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  4. SukiSolo
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    SukiSolo Senior Member

    Fair point about the weight distribution, but even in the shot with the crew well forward she looks a tad bow up. Could be waves, or as you say, helm a little too aft....;) The transom drag is a good indicator, or lack of. Some boats are quite sensitive to quite small changes ie a few inches fore/aft of weight, and bit of experimentation is called for.

    I wish you well as you optimise her. Thanks for the sketch, a full length top batten may help the roach stand out a little more .... though the sails seem to set pretty well.
     
  5. gggGuest
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    gggGuest ...

    Nice Job

    Couple of quick thoughts - I tend towards "off the boom" sheeting as well, more or less given up on having a block on the floor. However if you do that you will want to rethink the cleats each side of the mainsheet block as they will get very expensive in crew's trousers!

    A sleeve of sailcloth (eg polytarp) taped to the boom will stop the mainsheet drooping and catching heads on tacks. It needs to be loose enough that the mainsheet goes through freely. Just a rectangle about 3 feet long and probably less than a foot wide will do the job.

    Agree that trimming further forward will be a good thing.

    Not sure I've rip out the centre tank straight away, you may well get used to it and work out a technique. If it could be reworked a bit for a smooth top surface it may well be comfortable for the crew to sit on in moderate conditions and allow better fore aft trim than the conventional thwart.

    If you're doing a new jib anyway I'd look at making the clew as close as possible to the deck so that you can have the jib fairleads well forward: I find the ergonomics for the crew far better like than than with sheet impinging on their working area.

    Well done:)
     
  6. Segler
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    Segler Junior Member

    Thank you, everybody for your interest and suggestions. Lots to work with.

    As for the centerline tank, I have already removed the forward 2/3sand now have a much more navigable cockpit. I'm keeping the aft 1/3, under the helm. It still generates 160 lb of floatation and will also serve as my, rule-required, storage compartment.

    Also of interest: on her beam ends the boat is floating high and dry, with some freeboard. As we found out trying to get out of the marina on that fateful first outing. After righting, there wasn't a drop of water in the cockpit. In that type of roll-down, size and configuration of built in floatation would be irrelevant.

    The attached picture shows the 15 inch deep centerboard slot only some 17/18 inches above the water. Within reach of most people. Depending on your "gorilla factor" (arm length).
     

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  7. Richard Woods
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    Richard Woods Woods Designs

    Thats floating very high and usually means it will be easy for the boat to invert. New dinghy designs have less buoyancy to try to get the board near the WL yet still come up empty

    RW
     
  8. Segler
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    Segler Junior Member

    I can't picture how that would work. Can you reference some dinghies of this type? In any case, my hollow, wooden mast should keep me from going turtle.
     
  9. Richard Woods
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    Richard Woods Woods Designs

    I googled "dinghy capsize buoyancy" and this one came up

    http://hadrondinghy.com/about/

    a good explanation and a photo

    I was out today capsizing and then crew righting (deliberately) a very heavy 23ft open boat. It was surprisingly easy to get up again using three crew and the essential righting lines. Pumping out took longer....One reason my racing dinghy designs have open transoms

    Richard Woods of Woods Designs

    www.sailingcatamarans.com
     
  10. Segler
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    Segler Junior Member

    That's the part I am not getting! I know about the HADRON. It has to get wet before recovery.
     
  11. JRD
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    JRD Senior Member

    Very impressed with your build, well done!

    I converted an Australian NS14 dinghy into a single hander with quite a large mono rig. It floats very high on its side and wants to turtle. In strong winds when there is a lot of windage on the capsized hull i need to climb on to the dagger board to pull it upright. Not easy when its slippery and 2 feet above the water.
    Yours may be easier to pull up right but I think this is the same issue Richard is describing.
    Also if the vang is fully tensioned the sail won't spill water, so only way is to swim around and release it by which time the boat has turtled fully. It is worth trying a complete inversion under controlled conditions to see how it floats upside down and how hard it is to reach the board to allow you to climb on.
    Capsize dynamics is actually quite a large consideration in dinghy design.

    Enjoy your new creation, its definitely a testament to what can be done with good quality on a tight budget.
     
  12. SukiSolo
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    SukiSolo Senior Member

    I hope I have quoted one of the most pertinent paragraphs from the Hadron page. With due credit to Keith Callaghan and Richard for his reference, please correct me if I'm wrong.

    Quote Keith Callaghan

    'As with the original Hadron, the interior incorporates a low bow tank, a central longitudinal buoyancy tank and no side buoyancy: this allows the boat to sit low in the water after a capsize to facilitate righting, but the buoyancy comes into play once righted and two bailers soon remove what water remains. In the H2 we have added a shallow stern tank to further reduce the residual water and improve recovery time. A further possible refinement is the use of ‘slow draining’ buoyancy compartments under the side decks – the leeward compartment fills on capsize and when the boat is righted the water is allowed to drain away in about 20 seconds – the trapped water provides a temporary counterbalance for the helm as he clambers in over the weather gunwhale, thus minimising the chances of a re-capsize to weather. Another safety feature is the open transom, which facilitates re-entry of an exhausted crew after a capsize, should they be unable to get over the gunwhale.

    The absence of a full double bottom means that the generous hull depth can be fully utilised to provide an ergonomic sitting out position – no ‘straight-leg’ sitting out required!'

    End of Quote

    Ref http://hadrondinghy.com/about/

    If you like a Laser has it wrong too, in terms of too high a floating position when on it's side. Nat 12s' and Merlins are much better despite wide beam, as bow and low stern tanks plus centreboard/dagger case buoyancy allow good access to get on the board and prevent full inversion. Nothing like a true water test to fully prove it, I've had this conversation with a few n/a s'...;) I appreciate that in the US you don't have these 2 development classes but you must have some that have gone down that road.

    As for open transoms and self draining, I'm actually a bit more wary. It's obviously good to shed the water fast, but at the same time keep stability to manoevre and room to move in the boat. Sometimes a lower floor part with self bailer can be used to shift the last 'bit' but what you gain in room etc is worth it. Boom height and crew size comes into it as well. A completely open transom actually does take quite a side load from sitting out and the rudder, so a cross bar is often usefully employed. If you going very shallow in hull construction at the transom you do need some section height to avoid the hull cracking, though glass boats are probably more likely to, than wood ones, but dependent on construction. The low stern tank prevents the stern sinking and the hull adopting a bow to the sky angle - it has been done!.

    Too much straight buoyancy can be a dangerous thing ie windage as noted above, and access to the board.

    Hopefully you understand the drift of the type of arrangement that might work best on your craft. Keep up the good work.
     
  13. Richard Woods
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    Richard Woods Woods Designs

    I first used those slow drainers in the early 1970's, they certainly do work, especially on singlehanders

    Unfortunately the US has never had development classes as seen in the UK, nor indeed, with rare exceptions (IC10, 505) enough performance dinghies to have class racing anywhere

    I am in the UK right now, my last sailing here will be at QMSC on the 25th (I'm still looking for a boat to crew on, hopefully a RS400 again)

    I fly to the PNW on the 28th for the summer. So I hope to see you around some time. I will certainly be at the Port Townsend WBF as always

    Richard Woods of Woods Designs

    www.sailingcatamarans.com
     
  14. gggGuest
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    gggGuest ...

    Inversion is not necessarily a bad thing, often the reverse. A boat floating upside down won't drift off faster than you can swim and provides a reasonably stable platform that you can climb on and get your breath back out of the water before starting the next phase of the recovery.
    I've never found getting the boat to on its side to be much of a problem: it will come eventually, just be patient, and its a lot easier climbing onto a hull than trying to reach a high board.
    Personally I'll never own a modern boat that isn't self draining.
    The biggest challenge is always when the rig is to windward, which it usually will be in any breeze. On a two hander you can use the Australian Navy method, which when understood I find to work first time every time, but with a singlehander its trickier.
     

  15. Segler
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    Segler Junior Member

    Australian Navy method??
     
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