.

Cash prize of 250 GBP - Dinghy Design Competition

  • 28 Mar 2021 14:49
    Reply # 10244154 on 10211344
    Anonymous member (Administrator)

    “Halibut Special”

    Now I got the idea to try a fully fanned 3-panel JR for Halibut, essentially the top-section of the sails I usually draw. I have found that the top section of my sails are so efficient that they deserve to be tried alone on such a little nutshell. This will give a sail of half-decent sail area, which will reef well in two stages. The running lines will just be the sheet, halyard and lazyjacks.

    The boom has been shortened to avoid sheet tangles, and the sheet goes to a boomkin long enough to sheet the reefed sail or bundle to the centreline.

    The procedure of stowing the sail should sound like this:

    • 1.      Let go the halyard to dump the sail into its lazyjacks.
    • 2.      Haul on the running lazyjacks to raise the sail bundle and pin it to the mast. Longish batten parrels make this possible. Cleat the tail of the lazy j. at the mast.
    • 3.      Bring the sheet inboard,  reeve it around the sail bundle and cleat it off on the mast.
    • 4.      Unstep and lower the mast.
    • 5.      The boomkin may be taken in at leisure.

    With a little practice, this should be doable within 60 seconds, which is the maximum I would tolerate.
    One may well row the boat with the mast erected and the sheet in place. When clear of the beech, the lazyjacks are cast off, the sail hoisted and then one is under way (.depending a bit of wind direction and choice of leeboard and rudder/steering oar...).

    I kind of like this rig.

    Arne


    PS: Photo no.14 on Arnes sketches, section5

    Last modified: 20 Mar 2023 10:00 | Anonymous member (Administrator)
  • 28 Mar 2021 03:11
    Reply # 10242980 on 10242747
    Deleted user
    Anonymous wrote:

    I don't think it is off the topic Howard - after all, you are talking about a tender. And "out of left field" ideas can sometimes bounce around quite nicely. Its a clever idea - but it does seem to me a bit like a solution looking for a problem.

    A tender is a load carrier in its own right - so most likely it will be a bit beamy and stability under sail shouldn't  generally be a problem, I would have thought. It doesn't need more stability, what it needs is more waterline length, and I don't know how you would get that. Attaching an outrigger to a stumpy little tender might just kill its already meagre prospects dead, as a sail boat.

    Talking about something else, maybe something longer and lacking stability, might be a better application for your idea (though I think I would want to keep the oars out of the equation, they might be needed and it would be inconvenient to have to dismantle your new proa in order to negotiate a calm patch. Dual purposing is great - sometimes - which is why I am impressed but not yet quite convinced about David's thwart/off-centreboard idea - or Arne's thwart-cum-fish gutting board (but that might have been a bit of humour)).

    I saw a skinny little trailer boat in Tauranga (Katikati river) a couple of weeks ago - it might have been a little keeler with the keel lopped off, anyway the owner had busted up an old hobie catamaran and stuck one half of it on each side, with a reasonable little deck structure and hey presto - a trimaran. I should have taken a photo of it. That seemed sensible enough.


    I consider a tender more than just a way to haul food, water, and fuel and your butt from the boat to shore and back again.  The whole point of being able to sail it.... at least for me would be to be able to wander away from the mother ship, and explore the surrounding area.... further than you want to row, and have some fun doing it.  You are right about the oars.  There are some short fat little plastic kayaks I've seen that are pretty small, and even so in my experience it takes almost nothing to drive a kayak.  The idea is that you can carry more sail less chance of capsize.  Less skill required to keep it right side up.  Sailing dinghies seem to spend a fair amount of time upside down ;-)  I've never owned or sailed one.... mostly just seen kids racing them so excuse my ignorance.   In any case the outrigger would be an option you might use when you felt like it.   There is also the remote possibility that you might have an option of using it as a "life dinghy" as an alternate to resorting to the "death raft".


         In the reverse of the keeler cum trimaran, I know someone who built a catamaran from  two trimaran center hulls.  Also Richard Wood sells plans for several trimarans using beach cat hulls...........or build your own.  And then there's Vitamin Sea, a J-24 converted to a trimaran..... You can find articles on it and a Utube..... If you can dream it, somebody's done it  ;-)


                                                           H.W.  

  • 28 Mar 2021 00:18
    Reply # 10242747 on 10211344
    Anonymous member (Administrator)

    I don't think it is off the topic Howard - after all, you are talking about a tender. And "out of left field" ideas can sometimes bounce around quite nicely. Its a clever idea - but it does seem to me a bit like a solution looking for a problem.

    A tender is a load carrier in its own right - so most likely it will be a bit beamy and stability under sail shouldn't  generally be a problem, I would have thought. It doesn't need more stability, what it needs is more waterline length, and I don't know how you would get that. Attaching an outrigger to a stumpy little tender might just kill its already meagre prospects dead, as a sail boat.

    Talking about something else, maybe something longer and lacking stability, might be a better application for your idea (though I think I would want to keep the oars out of the equation, they might be needed and it would be inconvenient to have to dismantle your new proa in order to negotiate a calm patch. Dual purposing is great - sometimes - which is why I am impressed but not yet quite convinced about David's thwart/off-centreboard idea - or Arne's thwart-cum-fish gutting board (but that might have been a bit of humour)).

    I saw a skinny little trailer boat in Tauranga (Katikati river) a couple of weeks ago - it might have been a little keeler with the keel lopped off, anyway the owner had busted up an old hobie catamaran and stuck one half of it on each side, with a reasonable little deck structure and hey presto - a trimaran. I should have taken a photo of it. That seemed sensible enough.

    Last modified: 28 Mar 2021 00:43 | Anonymous member (Administrator)
  • 27 Mar 2021 14:32
    Reply # 10241512 on 10211344
    Deleted user

    Slightly off the topic, I've thought a lot about the possibility of marrying a cheap plastic kayak to a stitch and glue dinghy using the oars so that a small tender could become a reasonably stable sailing dinghy.  On one tack it would be like a Pacific proa, (ama windward) on the other tack like an Atlantic proa (ama leeward).  There could  be a small piece of plywood side decking attached between the oars both to hold the assembly in diagonal and to hike out on.   It would add considerable stability for sailing, and would only be used while sailing obviously.  Otherwise the kayak would be another tender.  

  • 26 Mar 2021 09:39
    Reply # 10236955 on 10211344
    Anonymous member (Administrator)

    David T: for me, the definition of a superyacht start somewhat smaller than that, but as I have rarely sailed anything bigger than 35 feet, I reckon that may be due to personal experience! 

    I suspect that the original size limit was put in place to avoid scarf joints in standard sheets of plywood, for both simplicity and to make it seem simple enough for people with fewer skills to have a go, or to be able to build a rough version in very short order.  Perhaps someone who was involved in those initial discussion will jump in and add more, but as the prototype build will be undertaken by a group of unskilled 12-14 year olds as a 'service' activity to support the JRA, simplicity of build will still be a desirable virtue.

    Graeme - thank you for splitting the discussion.  That is a good move, but I don't see any reason for you to apologise.  Apart from the fact that the topic of dinghies and tenders is similar to discussions about cooking with gas on boats - 25% logic, 25% personal experience and 50% emotion - with a corresponding lack of 'correct' answers, the forum postings in this topic are a good conversation that went sideways a bit.  The original concept was definitely tending to towards a tender, but the idea of a junket boat is interesting.  Perhaps there is a future design competition in that - a junket boat/camping dinghy or similar.

    However, someone else would have to step up for the prototype build of that one.  We will use a basement room at school to put the boat together.  A colleague and I just experimented with a bench and we reckon that anything much more than 11' would be impossible to get out in one piece!

    Lastly, as well as the concepts on this forum, there are a couple of entries on my email (which I have purposefully not looked at yet) and a couple more statements of intent, so I am still looking forward to seeing them all and sharing them on the website.

    Best wishes to you all and good drawing to our designers,

    Mark


  • 25 Mar 2021 22:33
    Reply # 10235501 on 10235426
    Mark wrote:

    I do not think the committee will object if I unilaterally relax the length requirement and say that all designs will be considered, so long as they also meet the requirement of being useable as a tender to something less than a superyacht.

    Mark

    That still seems to narrow the scope down below the ~ 4m dinghies that have been finding favour with some of us as potential Junket boats. Where does the Superyacht bracket start? 80ft? 120ft?

    However, since I once towed my 11ft 6in dinghy down Channel behind the 42ft Moody that I was able to borrow from the company I worked for, I'll take that as permission to go for a boat of that size - able to take two large people or three smaller ones at Junkets, not too much of an investment in material, capable of being built in a domestic garage, and so on, so it doesn't feel altogether like a pointless design exercise provided that the building process is easy enough for a first project.

  • 25 Mar 2021 22:33
    Reply # 10235500 on 10211344
    Anonymous member (Administrator)

    David D wrote:

    But what started as a competition to design a junk rigged 8 foot tender has morphed into something else entirely which I'm not quite sure where it is going.

    I think it has morphed into a discussion about what the design criteria should be, including some quite strong arguments against the committee’s stated criteria. Which is a little unfortunate.

    I feel sorry for my part in confusing the issue.

    Lets start again.

    • 1.    The design competition has so far, produced two concept proposals which are close to the committee’s stated criteria: Arne’s 5-plank Halibut with leeboard, and David T’s 3-plank model with off-centreboards and buoyancy tanks.

    Both designers have expressed misgivings about the committee’s requirement of 8' , but have never-the-less made a positive contribution.

    • 2.    An alternative line of thought has converged, with the suggestion that a larger boat might also be worth considering.
    • 3.    The length restriction has been relaxed – but it still has to be suitable for a tender.

    So far so good.

    In fairness to the committee, who represent and speak for the wider membership, (which the forum contributors generally do not) I think any further discussion about alternative concepts should be shifted to another thread, otherwise Annie is right, it really is throwing cold water on the committee’s dinghy design competition.

    All discussion of “junket boats” and other quite different proposals now risk crippling this thread.

    I feel sorry to see that happen, and I am going to edit some of my waffle out of this thread now, and transfer my alternative suggestions to a new thread – “Junket Boat”.

    By “Junket Boat” I mean something around 4m, which is too big for a tender and therefore does not belong to this thread.

    I invite David W, David D and others to do the same. There is no reason why two threads should in any way be seen as competing with each other – its just a different topic, that’s all.

    This thread should remain open for David and Arne to progress their concept designs, if they want to, and I hope they will. And I hope there will be some other contenders too.

    A sailing tender is a great idea, and if someone can make a seriously portable junk rig to suit one, then a real advance will have been made and the prize will be well-deserved. In my opinion the real challenge is going to be in the rig, rather than the hull, and I am going to leave it there.

    (PS I love that little piece from Jan)

    Last modified: 26 Mar 2021 01:43 | Anonymous member (Administrator)
  • 25 Mar 2021 22:10
    Reply # 10235448 on 10211344

    "JRA Dinghy competition
    Back in 2017, a few members proposed to the committee that the JRA supported a project to design a small dinghy that could be used with different types of junk rig."

    I've been trying to remember the first time that we were saying "wouldn't it be good to have a fleet of little junk rigged dinghies zipping about the bay when we meet up?" I've failed. Whenever it was, it was back at the dawn of history. Probably in the '80's, as it's cropped up at regular intervals all the time that I've been sailing under the rig.

    Will anything come of it this time? Who will actually commit to building whatever we designers come up with (apart from the Chair's undertaking to build the first one)? How about letting us know, you who are actually in the market for a JR dinghy design, that you really intend to build, what floats your boat? Make yourselves known. Give us a design brief yourselves, as distinct from the design brief proposed by the Committee, that is, so that the successful design will be more likely to be one that meets it.

    Or are we simply designing a theoretically perfect boat that nobody wants to build? Yes, it's good lockdown entertainment, and exercises the little grey cells, but is there a point to it? 

  • 25 Mar 2021 22:03
    Reply # 10235426 on 10211344
    Anonymous member (Administrator)

    Well, that has struck up more - and more heated - discussion than I expected!

    I do not think the committee will object if I unilaterally relax the length requirement and say that all designs will be considered, so long as they also meet the requirement of being useable as a tender to something less than a superyacht.

    However, I do not think the idea or specification should be summarily dismissed. As several people have commented, there are no shortage of dinghy designs available.  Adding one more to the mix and making it available to members on the website will do no harm.  Although I was not on the committee when the original spec was written I think such a design could, for example:

    1. Provide a member who fancies building a boat with a chance to try it out on a small and simple scale.
    2. A design with a JR could easily be built with a simpler standing lug (and possibly that is a more logical choice), but may give some members an opportunity to experiment with making their own sails, or to try out their own ideas for sailmaking.
    3. If the design is simple enough, it could provide a solution to a cruising member who needs a quick knockabout dinghy when their inflatable catches a bad case of sharp rocks.
    4. Through any or all of the above, provide members with just the impetus and confidence needed to take on a larger and more ambitious project.
    5. And of course it has already generated some good healthy discussion.

    Making information available on the website gives members an opportunity to play, adapt and try out their own ideas based on a concept that is freely available, much as the junk rig community has been doing for years. There is already a wide range of opinions and information on the forums about dinghies in our community - adding one or more potential designs to the mix is an extension of those discussions, as is this forum topic!

    I am enjoying some of the discussion here and looking forward to examining some of the ideas that are generated, and then having a go at building one.

    Mark


  • 25 Mar 2021 21:20
    Reply # 10235353 on 10211344

    "Rat! Let's have a competition to design simply the best little boat ever!"

    "Great idea Mole! We just have to make sure the competition suits my skill-set so that I win, otherwise I'm going to pour cold water all over it!"

    "Right then Rat, the first thing is that it has to be cold water proof!"

    "Of course it will be cold water proof if it's a boat, silly Mole!"

    "No Rat, not the boat, the competition!"

    And so, in the full light of their different expectations, the two friends set about designing the jolly little competition, for there is nothing, simply nothing, better than messing about with design competitions. 


       " ...there is nothing - absolutely nothing - half so much worth doing as simply messing about in junk-rigged boats" 
                                                               - the Chinese Water Rat

                                                              Site contents © the Junk Rig Association and/or individual authors

Powered by Wild Apricot Membership Software