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So back to Dinghy Development and a rig idea.
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iGRF View Drop Down
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    Posted: 21 Nov 12 at 10:14am
Not that I'm expecting an economic miracle turnaround anytime soon, but events are leading me to believe I may well be in a position to have another bash at the boat of my dreams. This time probably a una rig with a view to both lake and sea use and I still have the rig question buzzing about my head.

The idea I've formed is probably totally impractical, but so far as with all my ideas I can't see anything wrong with it so I thought I'd present it to the hive mind to have cold water chucked at it.

Basically what I've always wanted to do, is mimic the raceboard rig and seeing the way the EPS rig is supported gave me the bones of an idea.

The Gist of which is to use a device extending the bow/nose of the boat up and back in an arch to provide a fixed pivot point about at the height and position that the Eps rig is supported. Then with a similar but pivoting bearing the rig can be cantilevered with the base in a track and pivoted fore and aft.

So, I get a rig which for upwind can be low profile long draft foil wanged down to deck level, like we do with our boards for the upwind leg, then for off wind the mast can go dead upright or even top ahead of the base to raise the sail higher and clew forward.

So, problems please.

Oh why do I want to do it this way? It enables a more powerful rig than I might otherwise be able to handle to be efficient upwind with less righting moment and subsequent greater power off wind. I'll not dwell on my other desire to gybe the rig round the front of the boat, that would be a bonus if I could achieve it, but for the moment, lets just discuss the pro and cons of a cantilevered rig that can be raked fore and aft, if anyone's seen it done before or can think of problems I might have missed etc etc.

Edited by iGRF - 21 Nov 12 at 10:17am
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sten View Drop Down
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Posts: 208 		Post Options Post Options   Quote sten Quote  Post ReplyReply Direct Link To This Post Posted: 21 Nov 12 at 10:35am
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Posts: 611 		Post Options Post Options   Quote Noah Quote  Post ReplyReply Direct Link To This Post Posted: 21 Nov 12 at 10:42am
Love your 'blue sky' attitude Graeme, but for the life of me I can't see how you will get sufficient rigidity into the supporting structure to keep the mast-head where you want it to be without enormous weight penalty - and that weight will be just where you DON'T want it, up at height. Go on prove me wrong.  Smile
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Post Options Post Options   Quote Guests Quote  Post ReplyReply Direct Link To This Post Posted: 21 Nov 12 at 11:06am
Nothing wrong with the concept of a raking rig, but the device you describe sounds like it might put weight fwd, and be draggy, expensive, a pain to rig and difficult to put a cover over.

If you rig your unarig in a mast pot like a Laser, but elongate the top of the pot fore/aft into an oval, that would allow the rig to fall back upwind and forward off wind.
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Posts: 2202 		Post Options Post Options   Quote pondmonkey Quote  Post ReplyReply Direct Link To This Post Posted: 21 Nov 12 at 11:17am
Just to be clear from Page 1, please could you confirm commercial intent is...

a) definitely to market to y'all and revolutionise the archaic world of dinghydom, t**sers

b) something for me to mess around in and I enjoy this side of my hobby/sports

c) it's a bit of a laugh for me, if a commercial opportunity to licence it develops organically, then who am I to say 'no' to a fat cheque

d) I am the next 'Lord' and about 5 posts away from clinically certifiable ranting
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Posts: 346 		Post Options Post Options   Quote Kev M Quote  Post ReplyReply Direct Link To This Post Posted: 21 Nov 12 at 11:24am
What would be the benefit of pivoting the mast around a point 25-30% up form the bottom instead of pivoting it around the foot of the mast like boats are already?
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PeterG View Drop Down
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Posts: 822 		Post Options Post Options   Quote PeterG Quote  Post ReplyReply Direct Link To This Post Posted: 21 Nov 12 at 11:37am
<i>So, I get a rig which for upwind can be low profile long draft foil wanged down to deck level, like we do with our boards for the upwind leg</I>

Tacking might prove interesting!



Edited by PeterG - 21 Nov 12 at 11:38am
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Posts: 8956 		Post Options Post Options   Quote Rupert Quote  Post ReplyReply Direct Link To This Post Posted: 21 Nov 12 at 11:40am
Can you not do something similar with high and low aspect lateen rigs, set on a bipod mast?

As for the gybing round the front thing, Grumph - try taking a couple of purchases out of the EPS mainsheet, and allow the sail to go right forwards in a blow. Then swim back to the boat and try again...
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Posts: 3958 		Post Options Post Options   Quote winging it Quote  Post ReplyReply Direct Link To This Post Posted: 21 Nov 12 at 12:13pm
have the mast foot go into a slot or gantry in the deck, like the way an old boom used to slot into a mast.  That slot could actually form part of, or be mounted on a rotating stump, like on a low rider moth, so the mast can rotate as well as go fore and aft.  You'd need some sort of string sytem to shorten and lengthen forestay and shrouds, but that bit would be easy. 

I have here my very shallow kevlar hull thingy which is so narrow I think it needs wings.  It also has a longer than necessary daggerboard slot.  I think it could be your start point.  I will take pictures and you will see what I mean.
the same, but different...

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iGRF View Drop Down
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Posts: 6499 		Post Options Post Options   Quote iGRF Quote  Post ReplyReply Direct Link To This Post Posted: 21 Nov 12 at 12:39pm
Originally posted by Peaky

Nothing wrong with the concept of a raking rig, but the device you describe sounds like it might put weight fwd, and be draggy, expensive, a pain to rig and difficult to put a cover over.

If you rig your unarig in a mast pot like a Laser, but elongate the top of the pot fore/aft into an oval, that would allow the rig to fall back upwind and forward off wind.


I'll answer this and hope to address all the other questions.

Yes it will put weight forward but then so I've noticed and always wondered why, do other boats it's only with my increased understanding of the huge loads forward and the requirement presumably of the leverage being place aft to overwhelm them that I now accept the mast should be that far forward, so having said that.

Will a swept up built in carbon retaining bridge be much heavier than a conventional deck? Hopefully not.
A mast track can be alloy and when the rig pivots aft as much as I want it to the weight will travel that way. Also bear in mind if you pivot the rig around a more central point than just raking it with a fixed foot, the centre of effort doesn't move aft as much because some of the sail moves forward in the raking action.

Yes it might be difficult to put a cover over with a big sticky up bow, point I hadn't thought of. I'm wondering wether I'm worried about that at this stage. er no don't think I'm worried about boat covers hate the damn things anyway..

As to the weight up top, shouldn't be any different from any other carbon masted rig and as I said when it's raked back even less of a problem for me. Tacking yes you'd have to uncleat let the rig raise up, tack then slam it down again. But only if you were using the rig cranked right down and that would not necessarily happen always, in light conditions you'd keep a more vertical rig.

I think to get a handle on what I'm talking about you perhaps need to check out the EPS stay system, it's dead simple and super easy to rig so all I'm talking about is doing away with the forestay and shrouds and building a slot for the top and securing the foot in a sliding mast track, with perhaps a bridge at the rear to slot into in the upright position.

I know, it needs drawings, they're at home and very sketchy at the moment.

Edited by iGRF - 21 Nov 12 at 12:44pm
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