Plywood Boat Design/Build/Race Competition From SNAME Norcal

Discussion in 'Boat Design' started by sname5ply, Dec 3, 2009.

  1. sname5ply
    Joined: Dec 2009
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    sname5ply Junior Member

    Thanks for the info


    Thank you for the info on the boats built in your contest. I think it is especially enlighting to realize that only half the labor is in the hull. This carries over to the design as well. My approach to the 5ply contest rules was rather hull-centric with less thought going into the rig. But now after producing a few preliminary designs, I find that my chosen rig, a windsurfer sail, is dictating many of the design choices.
  2. cor
    Joined: May 2008
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    cor Senior Member

    Anyone familiar with building houses knows that when you get the walls and roof up it LOOKS like you are almost done. Then comes the wiring, plumbing, painting, flooring, etc.

    Boats are the same way, you get the hull together and think wow I'm almost done. Then comes the mast, sails, rigging, engine, wiring, etc.

    On any boat bigger than a canoe, the hull is only a small part of the cost and time.

  3. sname5ply
    Joined: Dec 2009
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    Location: Alameda, CA, USA

    sname5ply Junior Member

    SNAME 5ply Challenge Update

    SNAME 5ply challenge entries are now up on a "contestants" page on the SNAME 5ply site. Here's a link:

    The contest is still open to additional competitors, but all future submittals are not eligible for the Drawing Submittal portion (10% of overall score) of the contest and will be automatically ranked below current competitors in the order which submittals are received. We are ever hopefull for a couple more entries to join us on the water in May.

    Best Regards,

  4. PAR
    Joined: Nov 2003
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    Location: Eustis, FL

    PAR Yacht Designer/Builder

    I haven't been paying attention to this thread, then noticed the Tom.151 asked my opinion of a 5 sheet development class or contest.

    Personally, I'm not really excited about these types of limits. I'd rather see approaches to this sort of thing address the major concerns that small boats like this attempt to solve.

    Cost to own, use, live with, ease of setup/tear down, equipment requirements, maintenance, user friendliness, etc.

    Too often even small bleachable craft require costly sails, fittings, hardware and are more trouble then they're worth to set up, considering the performance or capacity you can get out of them.

    If I was to recommend a new development class, I'd require a common sail plan, one off a free standing, currently in use boat. Maybe the jib off of one and the main off another, just to keep the playing field level and cost down. Everyone can find a Laser sail (for example), even used in fairly good shape, pretty cheaply. The rig should be free standing, which eliminates the need for a lot of expensive equipment and eases setup/tear down too.

    The hull should have a LOD, LWL, WL beam, dry hull weight and flare limitations to keep things reasonable, but not much else. Of course mono hull only, retractable appendages desirable as in all beach boats. Wings? Sure, why not, but they have to be fixed angle of incidence, which will keep all but the most determined at bay.

    This will make folks think more about the design, rather then the number of sheets they have to work with. I currently have a design that fits this brief, except it uses it's own sail plan (though this could be matched to a production offering), and it even has a wing. It uses far more then 5 sheets (12), but then again can easily carry 4, though is intended as a solo or crew of two boat. If you eliminated the foredeck (I consider a requirement for anything except a rowboat) and the buoyancy chambers (another one of my requirements in small craft, so call me annal) it could be built in 7, maybe 8 sheets and plane off well into double digit speeds. Of course with the changes, it can swamp, will be a lot harder to right after a capsize (considering it's speed potential, a real probability) and will not stand up to the pounding designs like this have to take.

    Or, you could play around with the next want-a-be PD Racer like craft or as I like to call them (only around Mik Storer of course) concrete mixing tub sailors with 5 sheets or less.

    Too often self promoting contests serve to offer up the "usual suspects" and little real innovation. Real innovation usually addresses the common issues and with boats this size theirs plenty to work on. So, instead of cuteness in a 5 sheet box, how about clever engineering, with a new approach to time honored setup/tear down problems, beaching and over nighting issues, cost reduction on a grand scale, but having enough "performance" left to piss off the plastic products on your local puddle. And wouldn't it be cool if they didn't bother to paint anything, just left it raw epoxy coated, so the frozen snot sailors could drool and complain, about how much trouble it's going to be, as you show them nothing but your transom.
  5. Tom.151
    Joined: Jul 2009
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    Tom.151 Senior Member

    Thanks for giving us more of your thinking on this... and it's immediately obvious that there are many valuable ideas for a more refined rule-set without stifling development.

    When I think about rules for other people's boats I too take the "stock rig" approach. When I want rules that I have to follow I think of more open rig/sails rules. (I like to pretend to myself that I have good ideas for more effective rig/sail designs than stock boat rigs) But I heartily agree that that is a potential high-dollar aspect of any small boat build -- so... maybe a multi-dimensional rig/sail rule. (A) free standing only, (B) production rigs (mast and sails) of total 100% fore-triangle sail area less than nnn sq ft, (C) self-built sails and rig of of total 100% fore-triangle sail area less than 90% (or some other number) of nnn sq ft, That's just me, and I'd prefer no limit on rig height either, just upwind sail area.

    I like your dimensional box versus 'n-sheets of ply' rule - it would essentially cap the total hull surface (less hiking wings) area under most situations and would provide a bounding box that allows more creativity without being problematic for enforcement.

    PAR, when you mention "Wings" - what specifically do you mean by that? And by "fixed angle of incidence" ?

    If you meant hiking wings or hiking racks then I'm all in. I've been playing with a winged beast design for many years that would never have a rule or class under which it could run.

    Ah, more golden nuggets from PAR... "number of sheets only" could drive the design away from safety/buoyancy. So also add specific safety & buoyancy requirement rule(s). (A) Must be non-sinkable when fully flooded, (B) must support a weight of nnn pounds when flooded, (C) must have a positive righting moment when xx% of the mast is submerged, etc. (use a simple masthead pull down test)

    Love this little bit!!! I immediately thought of how the Everglades Challenge rules provide a filter through which the boats mast pass in order to compete (passing under fixed height bridges and between bridge spans - in order to be able to get down the course) A development class that had such filters could do just what PAR suggests. Besides such filters as (A) the EC-type filter - there could also be requirements for boats in the "overnight or raid classification" to (B) have horizontal surfaces of a size sufficient for x number people to lay prone (language to be refined of course - but you get the idea), or (C) able to demonstrate the ability to go from "ready to transport by trailer" to "in the water ready to sail" in less than so many minutes.

    Still, I do like the idea of some kind of a materials limitations. Such as (A) "all exterior hull panels, decks, and interior bulkheads must be plywood", (B) surface sheathing in fiberglass allowed (no carbon - except in local reinforcements for rig/hardware loads)

    Myself, I'd prefer there to be a "no ballast" rule of some kind - to place the burden for righting moment onto the hull shape and scantlings (RM based on a pull down rule would also at some point influence rig height).

    ?? Maybe time for a new thread to take this in it's own direction ?? PAR??
  6. sname5ply
    Joined: Dec 2009
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    sname5ply Junior Member

    But what about the submitted designs?

    When I posted yesterday I figured there'd be some commenting on the boats that have been entered. So far we have a Proa, a Scow, and a multichine hull tailered to a doner 120 rig. If we are lucky we'll have a 3 or four panel boat from another entry that I'm coaxing to enter. I think it will be very interesting to see how these boats perform in the flesh. I'm also pushing our current entries, (including myself) to offer up some ideas for the inovation this portion of the contest.

    The link to the contestants page is

    Best Regards,

  7. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    Wings? Horizontal (or nearly so) foils is what I was looking to avoid. Well, not so much avoid, but discourage, as it takes considerable skill and experimentation to make fixed foils work reasonably well across a wide range of sea states and if successful, changes the performance dynamic completely.

    Essentially, I was attempting to level the playing field so the "usual suspects" or those that have a 6 month advertising contract with the sponsor don't end up as "honorable mentions" or worse, winners.

    I think cost is a primary consideration and no "exotics" (fabrics) rules could apply, including rigging reinforcement. If you can do it in carbon, you can do it a little heavier in regular cloth. For the cost of a few yards of carbon I can sheath a whole small boat with 8 ounce cloth. These things add up and can make or break a back yard project, particularly experimental ones.

    Ballast I have no issue with. If you think you can handle it, then go for it, but ballast in small craft brings a whole new set of issues to the table for the designer. I think possible limits on movability or type, but it's debatable just like everything else in yacht design.
  8. Perm Stress
    Joined: Sep 2009
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    Perm Stress Senior Member

    I would like to enter.

    where will be the sailing done?

  9. sname5ply
    Joined: Dec 2009
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    Location: Alameda, CA, USA

    sname5ply Junior Member

    5ply Challenge Regatta Location

    Perm Stress,

    All racing for this challenge will happen in Alameda Estuary which is in San Francisco, California, USA. It would be great to have you as a fellow challenger. If getting your boat to our location is not feasible, maybe you could use the concept and organize your own challenge where you are at.

    There are other details on the 5/ply Website giving the our proposed regatta dates and elegibility requirements. Here's a link to the schedule:

    Please note that all current contestants have agreed to a policy of allowing others to join, but submittals after the December 15th deadline are not eligible for the Design Submittal portion of the contest. Late submittals will be ranked in the order that they are received. (see this link for the scoring scheme:

    Thank you for your interest!



  10. KSONeill
    Joined: Jan 2009
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    KSONeill Junior Member

    How is the proa supposed to be steered? The CE is way aft and no rudders are shown.

    K O'N
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