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iGRF View Drop Down
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    Posted: 05 Dec 14 at 12:20pm
Originally posted by davidyacht

Can't help but think that you might be better doing away with the central "pod", but if you do have the central pod, should you raise the outriggers to ensure that you have one out of the water at all times,, reducing wetted area


That is the general idea, i doubt I'll be able to keep one clear all the time but certainly the central 'pod' will be deeper than the 'outriggers' without a pod all you have is a small cat which we all know are the spawn of satan.

By having the pod, you deal with the rig loads centrally, there will be no lee bow induced trips, if I get the volumes right in light airs it could be possible to get the stern clear at the very least one of them and if I get the rocker right the front bit could plane off wind, a lot of could and ifs, but that's the goal. The last one planed really well but stuck in the light stuff and in waves, this one will deal with the waves by piercing and should still plane on flat water.

Edited by iGRF - 05 Dec 14 at 12:24pm
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JimC View Drop Down
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Post Options Post Options   Quote JimC Quote  Post ReplyReply Direct Link To This Post Posted: 05 Dec 14 at 12:25pm
Clinker's a damn silly way to build a boat in the 21st century: exceeded only by fake clinker... You could make a kind of argument for a pseudo clinker where joins between panels on stringers are overlapped rather than butted to avoid butt joints but still minimise end grain exposure, but you'd regret it as soon as you got on to fairing and painting the bottom...

I've been rebuilding a Moth with semi cold moulded panels. There are two stringers between "chine" and hog, and in some ways really would have been a lot more sensible to do them as separate chines, but the only trouble would be all the butt joints. The strongest advice I can give is always work from the centre to the edge and always have three edges of the panel unconstrained so they are trimmed later rather than try and make them fit. Multiply this advice a hundred times if the panels are heavily curved.

I really strongly advise using glue. Look into the foaming urethane glues, they are far less hassle than epoxy if not quite as friendly to approximate carpenters. I can't see a boat with mechanical fasteners only working unless its just ridiculously heavy. Nails will just get looser and looser.

Edited by JimC - 05 Dec 14 at 12:26pm
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Post Options Post Options   Quote iGRF Quote  Post ReplyReply Direct Link To This Post Posted: 05 Dec 14 at 12:34pm
I can see I'm going to need to know these terms, chine I know 'hog' which bit is that? I've also heard the term 'hog' stepped when used to describe masts so is that the deck or the base near the keel?

Also I thought those new wonder of the age plastic nails kind of melted into whatever they are driven into, either way I'd only use them as 'tacks' then epoxy tape after.. I guess, it's all new territory this having to do it yourself rather than instruct someone else poor pensioner stuff.
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Post Options Post Options   Quote JimC Quote  Post ReplyReply Direct Link To This Post Posted: 05 Dec 14 at 12:48pm
Hog is the strip down the middle of the boat.



I'm never really convinced by tape joins. I suppose I've seen too many leaky side tank to floor joins over the years, endlessly replaced and leaking again two weeks later... I think the trouble is that there's not that much stopping the seam opening. They're a valuable addition to glued joints, but not in my opinion a substitute.

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Post Options Post Options   Quote getafix Quote  Post ReplyReply Direct Link To This Post Posted: 05 Dec 14 at 12:54pm
Originally posted by iGRF

 
That is the general idea, i doubt I'll be able to keep one clear all the time but certainly the central 'pod' will be deeper than the 'outriggers' without a pod all you have is a small cat which we all know are the spawn of satan.

By having the pod, you deal with the rig loads centrally, there will be no lee bow induced trips, if I get the volumes right in light airs it could be possible to get the stern clear at the very least one of them and if I get the rocker right the front bit could plane off wind, a lot of could and ifs, but that's the goal. The last one planed really well but stuck in the light stuff and in waves, this one will deal with the waves by piercing and should still plane on flat water.

um, doesn't the "pod" kind of make this a trimaran, which I guess must be one worse than a cat on the rings of hades scale?

FWIW it looks like you're trying an iteration on the theme of a monohull 'version' of a cat.  A boat that will have less wetted surface area upwind (like a cat flying a hull?) but have extra stability downwind so you can have canting poles and silly kites to play with (like a cat?)

Maybe I've completely missed your point here, many apologies if so... but I just don't see what the harm would be in taking an A-class for a spin before you spend your dough, or a Shadow, or a Spitfire, an F16 or even a Vortex..... buy a cheapo Europe or something for that tiny pond, get yourself a speed machine for the sea side.
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Post Options Post Options   Quote davidyacht Quote  Post ReplyReply Direct Link To This Post Posted: 05 Dec 14 at 1:09pm
If you want to isolate the rigloads, why not build an aluminium space frame, that simply bolts to the hull structure, there is no need to have a hull to support this, just a dolphin striker to support the mast heel loads.  I agree entirely that a cat is the son of hades (I have as much prejudice against cats as you do against Merlins and Solos), but you run the danger of picking the worse aspects of a monohull and combining them with the worse aspects of a multihull, I suspect that you would be better commiting to one or the other ... though I admire your desire to innovate. 
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Post Options Post Options   Quote iGRF Quote  Post ReplyReply Direct Link To This Post Posted: 05 Dec 14 at 1:14pm
No, it's just a means of description it's intended to be and act like a mono, the v2 never felt like anything other than one unit, so I hope will this, the various 'bit's that go together are just being described in those terms. If no-one thought of connecting the cat hulls we wouldn't have the ribs we currently use.

My points in no particular order. 1)Not falling over 2)reducing wetted area to the sort of sized hull I would almost certainly fall over in otherwise, 3)Kick back centreboard without the need for flushing strips4)not necessarily having to hike let the heeling action work for me 5) retain fast tacking due to mono nature.

Other features: run all the ropes under the middle, rake the rig with either a lever or pulley system from below, have not such a tight sheeting angle with the waterline being more outboard.

Cats are too big for either club I'm at and anyway they are pretty boring corner bangers nobody seriously races them do they? AC & Ultra 30 things excepted.
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Post Options Post Options   Quote Noah Quote  Post ReplyReply Direct Link To This Post Posted: 05 Dec 14 at 1:16pm
Can't help but admire the blue-sky, out-of-the-box thinking. Gawd only knows if it'll work but good on you for trying.

Steam was our friend when bending ply thru tortuous curves 40 odd years ago!
Nick
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Post Options Post Options   Quote iGRF Quote  Post ReplyReply Direct Link To This Post Posted: 05 Dec 14 at 1:23pm
Dinghy bows have huge down pressure from the leverage and moment of the fixed mast, this came to me late in the day when trailing a boat to the water downwind and even a small puff was enough to make me drop the trailer, that is the fundamental problem that causes cats and some monos to dive, insufficient volume to withstand the downforce combined with the sort of rocker you need to make them go fast.

So this thing will have a lot of volume in the front bit and minimal in the aft bit given the nose should carry all it needs to stay afloat the rear is there to provide waterline length.
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Post Options Post Options   Quote iGRF Quote  Post ReplyReply Direct Link To This Post Posted: 05 Dec 14 at 1:27pm
Originally posted by Noah

Steam was our friend when bending ply thru tortuous curves 40 odd years ago!


Steam? How did you do that? Hmm I wonder we used to have a steamer for getting the creases out of clothing samples at exhibitions, would that work?
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