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Dragonfly hull construction has started:

Extra carbon goes on first

post-2679-036104100 1296645217_thumb.jpg

post-2679-048898800 1296645230_thumb.jpg

 

Carbon skin vacced on

post-2679-018408200 1296645242_thumb.jpg

Must try to get the perforated release film overlaps a bit smaller!

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icsternsmall.JPG

 

My experimental wide sterned Nethercott hit the water today... Conditions F2/3, gusty, sailing poor - very rusty. Right arm and wrist aching so much can hardly type...

 

OK, so how does it feel... Well, to be honest it makes a lot more difference than I expected. The stern wave is very obviously lower and flatter, so more pressure recovery going on I think. As Rob M predicted to me the bow is a good couple of inches lower when reaching, amazed its made so much difference. You can see the chine digging into the water some when the boat is heeled, this is especially striking sailing upwind with windward heel, which I tend to try and do. Water goes over the stern quite readily when heeled either way which is to be expected so more freeboard than a standard Nethercott is preferred. Or just keep the boat flatter of course. At least one other club sailor reckoned that the boat was noticeably quicker, and although it was good conditions for the Canoe which may have affected his assessment I think this change has added performance in that wind strength, but of course that was always where it was likely to gain. Lighter winds are likely to be a weakpoint, may be worse than I thought unless I try very hard to get weight forward as corner of stern is more likely to immerse than I thought. Stability... I didn't think it was more stable out there, but I do now I think. Was very rusty, had to slip off plank twice to avoid being teabagged, yet no real ropy tacks. Interesting to see what happens in breeze.

 

Blue Christmas? :lol:

 

Very nice.

 

How close are you to class B max?

 

P

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How close are you to class B max?

Class max beam? Not "Class B" max?

The vast majority of the boat is completely standard Nethercott. The extra structure starts roughly at the end of the tracks, which is two or three feet aft of the max beam position on the Nethercott.

This pic is probably the best for showing the extra structure.

IMGP2532.JPG

Important to remember this isn't an exercise in producing a race winning canoe: the idea is to have a relatively cheap and easy 305mm to the foot scale model to gain an idea of the pros and cons of the different stern treatments. If it turns out to be genuinely faster on the race track in the majority of conditions I shall be rather suprised and quite fascinated:-) Were it to be remotely competeive with any of the new designs I'd be utterly flabberghasted but it will be interesting to see whether I am less far or further behind the rest of the Nethercott sailors this summer.

I suppose if I were doing a really serious exercise I should build a minimum dimensions structure completely enveloped in styrofoam and add and remove bits to see what happens. Sadly I like the committment, time and workshop space. Oh, and build two of them and go two boat testing with the training partner I don't have.

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Thanks Jim, meant Beam Max, construction pic really helpfull. Didn't realize you were modifying what you already had (?).

 

P

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The Nethercot was developed to reduce the volume at the "stern" . Uffa's canoes of the fifties had quite a large stern and Proctor was asked to design a canoe with less volume at the stern. The Proctor mark 2 became the standard in the UK during the 60's but was still felt to have too much volume in the ends and the Peter Nethercot was asked to produce a design to remedy this. Jim Cs experiment is thus interesting, as it changes only one end and keeps the rest of the hull shape the same, ( the only way to test the effect of volume at the ends) and should shed light on why the Neethercot is superior to the Proctor. I have heard sailors say that the reduced volume aft helps to stop nosediving, although I'm not sure why this should be the case. The modifications could throw light on whether this is the case.

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the only way to test the effect of volume at the ends) and should shed light on why the Neethercot is superior to the Proctor.

Interesting back info, thanks. For my taste the Nethercott is too full at the sharp end, but that wasn't a quick fix to try... I did investigate pulling the bow in when I had to redeck the boat a couple of years ago, but the shell was about as willing to change shape as a VLCC is to change direction so I gave up.

 

Unfortunately I haven't been able to get the boat out the last two weekends so no further news.

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For my taste the Nethercott is too full at the sharp end,...

 

 

As an aside. Your Avatar looks like a pyranha mark 2, so I was wondering if you had any thoughts on how the pyranha, which was less full at the bow and fuller at the stern than the Nethercott, compares with the Nethercott.

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Your Avatar looks like a pyranha mark 2

 

But isn't:-). Its the Nethercott before it got the latest mods. I haven't sailed one of the Piranhas.

Now you mention it though the colour is very like some of the Piranhas. Oh well, never liked that colour anyway: I couldn't get my preferred paint colour.

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Morrison vs Dragonfly ( take 50mm off the skirt for the real hull size )

post-2679-067499500 1298719586_thumb.jpg

post-2679-024283500 1298719588_thumb.jpg

 

Looking at that flatter bottom section on the dragonfly reminds me of Steve Clarks 'Josie' hulls. Was sailing against Josie yesterday and it was amazing to watch her slip away from me off the wind, sounding like a drum as it skipped over the small waves. My flatpack was able to get away a little bit upwind, but I don't think by enough if we were racing triangles.

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Unfortunately I haven't been able to get the boat out the last two weekends so no further news.

Boat out again today. Started very light, and it does feel very sticky unless I take *extreme* care with trim and heel. No doubt in my mind that she's slower in that region. Got quite pleasant later, F3ish, and I do think the poor tack count has come down a bit, so the boat does seem easier to sail like this. On a fastish reach, I would guess 10 knots or that sort of area, the wake does seem extremely flat: in that sort of speed range I'm reasonably confident the boat is quicker. One other observation on this: I'm only evaluating the boat on flat inland water as I've got rather bored with salt water in recent years. Pitching in waves the tradeoffs will surely be very very different.

 

The handling is the key thing I'm interested in exploring, and so far (very early days) my thoughts are the wide stern is a bit easier.

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Looking at the two side by side perhaps I should have gone a bit more pointy?

started on the sliding seat last week, had to find somewhere flat, so was allowed (for one night only) to set things up indoors, aiming to make pattern and then mould, pattern in laser cut slot together form, all now glued and starting to fair in

post-20243-027248200 1298898771_thumb.jpg

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Finally photos to prove things have been happening while somewhat slower than in the past my new ride is getting much closer to hitting the water :)

post-21278-058914900 1300351703_thumb.jpg

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Finally photos to prove things have been happening while somewhat slower than in the past my new ride is getting much closer to hitting the water :)

post-21278-058914900 1300351703_thumb.jpg

 

Hmm... on second thought maybe it's a good thing that you don't bring that missile to the Worlds.

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That's very pointy and round, looks fast, but not going to the worlds? Shame if not

Some progress at home in the shed

post-20243-071783200 1300391091_thumb.jpg

pattern work for moulds, perhaps moulds this weekend?

post-20243-049161700 1300391133_thumb.jpg

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Dave's new ride.

Latest Maas/Stevenson hybrid by Clark

post-738-044135700 1300400194_thumb.jpg

USA 250 Code name SmokeShow

With any luck it will get wet in 6 days.

SHC

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Finally photos to prove things have been happening while somewhat slower than in the past my new ride is getting much closer to hitting the water :)

post-21278-058914900 1300351703_thumb.jpg

 

Hmm... on second thought maybe it's a good thing that you don't bring that missile to the Worlds.

 

 

That's very pointy and round, looks fast, but not going to the worlds? Shame if not

Some progress at home in the shed

post-20243-071783200 1300391091_thumb.jpg

pattern work for moulds, perhaps moulds this weekend?

 

 

I'm looking forward to getting the missile wet in the next few weeks, all going well top coat will be sprayed on next week while we finish the other parts off... mast and plank carriage has been taken from Miracle Drug.

 

Worlds?????? lost of question mark around getting there at this stage its very doubtful I'll get there but not for the want of trying just dont have the funds its that simple :(

 

 

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Dave's new ride.

Latest Maas/Stevenson hybrid by Clark

post-738-044135700 1300400194_thumb.jpg

USA 250 Code name SmokeShow

With any luck it will get wet in 6 days.

SHC

 

 

Looks great, what about your ride Steve????

 

Dave's new ride.

Latest Maas/Stevenson hybrid by Clark

post-738-044135700 1300400194_thumb.jpg

USA 250 Code name SmokeShow

With any luck it will get wet in 6 days.

SHC

 

 

Looks great, what about your ride Steve????

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Dave's new ride.

Latest Maas/Stevenson hybrid by Clark

post-738-044135700 1300400194_thumb.jpg

USA 250 Code name SmokeShow

With any luck it will get wet in 6 days.

SHC

 

 

I think I need a moment or 2 alone with this boat ;)

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Why is it whenever you guys post pictures of *your* workmanship I deeply regret having posted anything of mine?

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Why is it whenever you guys post pictures of *your* workmanship I deeply regret having posted anything of mine?

The camera lies quite a bit.

Don't worry it looks a whole lot less Gucci in the flesh.

SHC

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Dave's new ride.

Latest Maas/Stevenson hybrid by Clark

post-738-044135700 1300400194_thumb.jpg

USA 250 Code name SmokeShow

With any luck it will get wet in 6 days.

SHC

 

is this the final finish scheme? Hope so:

 

Very Wally- esque. Gorgeous.

 

Time for new wallpaper....

 

P

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Pretty close to the finished look.

There will be a cove stripe and boot stripe to hide the ugly edges of the carbon.

This may be the same grey as the non skid, but doesn't have to be.

I will let the owner decide.

And maybe even do it.

SHC

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Dave's new ride.

Latest Maas/Stevenson hybrid by Clark

post-738-044135700 1300400194_thumb.jpg

USA 250 Code name SmokeShow

With any luck it will get wet in 6 days.

SHC

 

really a nice one Steve.

 

Of course i'm interested in the differences to GER 78

 

did you change the hull shape ?

did the use of carbon outside the ply enable you to stiffen the hull wothout the foam and kevlar inside like it was done in GER78 ?

Is the foredeck carbon only or is there some thin ply under it ?

Will yo hit teh Min weight ?

 

Sorry for being such curious ...

 

Roger

GER 78

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Shape is different.

Different set of cuts and darts, they didn't woirk quite as expected, so things had to be made up on the fly.

I think after a few more tries I will have a better idea of what it is going to look like before it is finished.

This ply method really requires you to jam and improvise, which is fun as long as you can tolerate it.

I tried not using the core in the bottom, but using EPS bulkheads as per Phil Stevenson.

Didn't like the results particularly.

Don't think it's gonna make minimum weight either.

However Dave was ome for the weekend and seems happy, so it's good.

SHC

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Has anybody a rule of thumb, per the new rules, about the relative percentage (weight wise) of

 

Hull

Seat

Foils

Rig

 

Adding up to 100%, of course. Or 50kg.

 

Also, for the epoxy challenged (i.e. allergies),

 

PU glues? For dinghy that lives on a trailer and garage that is:

 

Gorilla

Titebond 2 or 3

 

Or others, if not too toxic. And thanks Steve for the tip on green resin- checking it out on some of the British Surfing sites.

 

I don't mind extruded polystyrene, as long as I don't have to melt it.

 

Using a thicker ply instead of cloth sheathing- for example, 4mm rather than 3mm, 6mm rather than sheathed 4mm, etc.

 

chine logs for 90 degree joints instead of fillets.

 

Any advice would be welcome.

 

-P

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Here are some figures I have what I have built is fairly close to these figures where it doesn't match up it because I've stuffed up or had help by a vacuum pump shitting itself...

 

 

Im not much help on the rest.....

 

 

Hull very approx 59% (includes hull, fittings, carriage and paint)

Seat 15%

Foils 7.4%

Rig 18.6% (includes mast boom and rope for all controls etc)

 

 

 

 

 

 

 

 

 

 

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That is a relief to know, as it's near my ballpark numbers so far...

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Original stressed ply Hollow Log was about 35kg for hull, 9 for seat, 6 for rig and 3 for foils. total 53 from memory. Unstayed mast was heavy, and high freeboard would have added a few kg.

No experience of PU glues.

Expanded PS foam absorbes water if the boat leaks but extruded foams start out heavier. I try to build boats which do not leak. I prefer thicker foam bulkheads of lighter material to support more ply. Coating the foam does not seem to help much with water absorption and adds a lot of weight.

3mm ply will bend to the shapes asked of it. Thicker ply will make a different shape with less round and more V and spring. Depends on your preferences.

Thin ply with interior kevlar skin seems to provide best compromise of cost, stiffness and durability.

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Original stressed ply Hollow Log was about 35kg for hull, 9 for seat, 6 for rig and 3 for foils. total 53 from memory. Unstayed mast was heavy, and high freeboard would have added a few kg.

No experience of PU glues.

Expanded PS foam absorbes water if the boat leaks but extruded foams start out heavier. I try to build boats which do not leak. I prefer thicker foam bulkheads of lighter material to support more ply. Coating the foam does not seem to help much with water absorption and adds a lot of weight.

3mm ply will bend to the shapes asked of it. Thicker ply will make a different shape with less round and more V and spring. Depends on your preferences.

Thin ply with interior kevlar skin seems to provide best compromise of cost, stiffness and durability.

 

Why Kevlar instead of carbon for the inside skin? I'm guessing because anything lighter than 200gsm carbon is super expensive?

 

I didn't know, or had forgotten, that Hollow Log was so close to minimum. That's really impressive. Was it as stiff as you'd like, globally and panel?

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Original stressed ply Hollow Log was about 35kg for hull, 9 for seat, 6 for rig and 3 for foils. total 53 from memory. Unstayed mast was heavy, and high freeboard would have added a few kg.

No experience of PU glues.

Expanded PS foam absorbes water if the boat leaks but extruded foams start out heavier. I try to build boats which do not leak. I prefer thicker foam bulkheads of lighter material to support more ply. Coating the foam does not seem to help much with water absorption and adds a lot of weight.

3mm ply will bend to the shapes asked of it. Thicker ply will make a different shape with less round and more V and spring. Depends on your preferences.

Thin ply with interior kevlar skin seems to provide best compromise of cost, stiffness and durability.

 

I have 2 lb extruded polystyrene. Were you using 1 lb expanded? I know I can get 1 lb extruded, but I wonder about compression strength and outgassing, although some are using 1 lb as bulkheads with striplanking, and a Gore Tex (tm!) valve. In surfboards. Long and Fish.

 

P

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The EPS foam I used was 11kg/m3 which is about 1 lb/cuft.

 

Kevlar is a better material for ply skins because it yields and hence takes load at a rate about the same as the ply. Carbon being much stiffer takes all the load and sometimes even fails before the ply is significantly deflected enough to start taking load. When the carbon fails the load applied instantly overloads the ply and it fails too.

Carbon makes a stiffer boat but a more fragile one. Its also easier to use and get a finish. I used carbon on the inside of the hull and kevlar inside the working deck.

 

Steve has obviously used carbon on the outside but I bet he gets one of the younger generation to do the sanding.

Good to see the new interest in the stressed ply canoe concept. It can make some nice shapes with small outlay on materials and no jig.

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More pics of what has been happening.....

post-21278-083067800 1301035844_thumb.jpg

 

post-21278-048974300 1301035895_thumb.jpg

 

First time I've painted in a proper spray both... wow amazing how much easier it makes the job, even I can get a decent finish :)

Non skid goes on the dance floor tomorrow, then Sunday start screwing fitting to the deck, now I must finish that plank asap... (its not far off at least)

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weight split seems like about

25 kg bare hull( inc paint but no fittings/ carriage)

4 kg carriage

8 kg seat

4kg foils

mast+rigging 6kg

boom 2 kg

fittings 1 kg

will be a bit more accurate when I have all these bits made

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Painting done,

 

 

post-21278-064458700 1301114036_thumb.jpg

 

 

Next photo should be a fully fitted out boat ready to sail (errr maybe still needing a plank to be finished off).

Plan is to sail at the upcoming Australian Champs and then go from there, Worlds look very doubtful at the moment it would take something from left field to make that happen.

As much as I want to have a shot at title defence I just don't know how I'll scrap the funds together to make it happen :(. I built this boat in the hope I could make it somehow...... some things just aren't meant to be I guess.

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Morrison 2 shape now off the mould and just in the process of decking.

 

 

Sigh.... Oh all the cool shit Steve Clark has to play with !!! WOWzers, that is one sexy looking shell. Well done.

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Morrison 2 shape now off the mould and just in the process of decking.

 

 

Sigh.... Oh all the cool shit Steve Clark has to play with !!! WOWzers, that is one sexy looking shell. Well done.

Wrong Steve Clark: This one is from across the pond & uses an extra E on the last name.

 

 

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+ e.

 

How sure are we this isn't just a right coast nom de plum?

 

:)

 

Years of posting to the contrary............

 

It snowed today. Forgive me.

 

Is the back end kind of like a convertible in a squall? Drive faster, and the drops don't fall on the back seat?

 

Dance Floor!

 

Paul

 

Hot boat. Me envious.

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+ e.

How sure are we this isn't just a right coast nom de plume1?

Now Concorde is out of service building two boats simultaneously on each side of the Atlantic is a bit impractical...

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Smoke on the water.

post-738-081426300 1302271034_thumb.jpg

Chasing Kaito and Willy up the beat

post-738-070459900 1302271015_thumb.jpg

And in spite of my vast bulk and some watertight integrity issues

(I didn't find and fill all the little holes)

The boat doesn't float that low.

John just managed to get a wave in between the lens and the boat in every picture.

post-738-065105700 1302271000_thumb.jpg

 

Mobile in March was pretty special.

There are things to sort out, but the first impressions are the boat is plenty quick.

SHC

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Morrison 2 shape now off the mould and just in the process of decking.

 

 

Sigh.... Oh all the cool shit Steve Clark has to play with !!! WOWzers, that is one sexy looking shell. Well done.

Wrong Steve Clark: This one is from across the pond & uses an extra E on the last name.

 

 

 

 

Yes sorry to the original Steve Clark for causing confusion. I'lll change logon name.

 

More pictures at http://www.intcanoe....ls.php?album=48

 

AngloSteve

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But He, like Mr. Lightfoot, could afford roadies known for their fabrication prowess. Or at least the ability to tune guitars backstage with a Korg TM-40.

 

:lol:

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could afford roadies known for...

I have a sudden vision of the wrong white powder being used as a filler...

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could afford roadies known for...

I have a sudden vision of the wrong white powder being used as a filler...

 

having made this mistake a couple times myself, coke based fairing compounds sand surprisingly well, and the resultant dust can be sold to fund the materials for future projects.

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I'm getting really close to pulling the trigger on the long coming IC. :o

 

I need to find a mast (used or new) or mast manufacturer:

 

unstayed

24 to 36" bury

1 piece

Gnav

19.5'

 

I know Phil used 3 (?) sections of different diameter, but wasn't totally pleased with the weight, Finn and ok masts are heaVY and so refined to be pointless, the MegaByte mast is elegant and eye popping $$$ wise. If there are mast suppliers to some of the other unstayed single hand dinghies, they are well hidden, at least in the US/Canada, and carbon tube manufacturers will not state any specifics.

 

So do I need to go to a NA?

 

Any input at this point would be welcome. Frankly, it's a bit maddening.

 

Paul

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I'm getting really close to pulling the trigger on the long coming IC. :o

 

I need to find a mast (used or new) or mast manufacturer:

 

unstayed

24 to 36" bury

1 piece

Gnav

19.5'

 

I know Phil used 3 (?) sections of different diameter, but wasn't totally pleased with the weight, Finn and ok masts are heaVY and so refined to be pointless, the MegaByte mast is elegant and eye popping $$$ wise. If there are mast suppliers to some of the other unstayed single hand dinghies, they are well hidden, at least in the US/Canada, and carbon tube manufacturers will not state any specifics.

 

So do I need to go to a NA?

 

Any input at this point would be welcome. Frankly, it's a bit maddening.

 

Paul

 

I have a mast in my shop that was intended for an unstayed IC rig. It was designed and built by Ted Van Dusen and is owned by Erich Chase. If you're interested I'll ask him if he wants to sell it.

 

Or you could ask Ted at www.vandusenracingboats.com to build you one. Masts are also in Erich's line of work - erich@chaseboats.com.

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#1- would you ask?

 

I will email Ted- he was a Famous Finn Sailor, no?

 

I tried googling Erich earlier, no satisfaction, so thanks for the address.

 

Thanks Chris,

 

Paul

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I'm getting really close to pulling the trigger on the long coming IC. :o

 

Paul,

 

This should be interesting. :D Are you in a position to reveal your design?

 

I need to find a mast (used or new) or mast manufacturer:

 

unstayed

24 to 36" bury

1 piece

Gnav

19.5'

 

I know Phil used 3 (?) sections of different diameter, but wasn't totally pleased with the weight, Finn and ok masts are heaVY and so refined to be pointless, the MegaByte mast is elegant and eye popping $$$ wise. If there are mast suppliers to some of the other unstayed single hand dinghies, they are well hidden, at least in the US/Canada, and carbon tube manufacturers will not state any specifics.

 

So do I need to go to a NA?

 

Any input at this point would be welcome. Frankly, it's a bit maddening.

 

Paul

 

The problem with adapting an existing mast is that the IC has so much more righting moment than any other similar sized boat with an unstayed mast. Getting enough stiffness without excessive mast diameter is always going to be a problem. On 21C.H.L., Phil had to add diamonds and a forestay to reduce the bending. My preferred option would be to use a large diameter at the base, say 100mm, then taper down quickly to a set of spreaders (raked forward) at say 500mm above the deck. Thereabove the mast can be a standard section, stayed, with normal sized spreaders (also raked forward) midway between the lower spreaders and the hounds. At the bottom, the stays would attach to the mast just above the deck bearing. Sort of a double spreader diamond stay setup. I envisage that the sreaders would only rake forward say 10 degrees as sideways bend is the biggest issue.

 

Mal.

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oh hell, why not...

 

doing this without epoxy leads me to 6mm! ply. 3M 5200, Titebond 3, etc. desperate times. What is 'under the waterline' mean

for an IC?

 

so she has to be as small as possible. Looks like Harken 27mm track is in the running, according to Harken Industrial, it can be cantilevered. Light too.

 

Looooow prismatic. over 300 Vacanti designs, BUT have to fine out a few things- what is th Bethwaite hump anyway?

 

I'd like to do an epp wing, but 15 sheets of epp later all I've found possible is an 18" chord, which equals a little less than 30 sq feet on a a 19' span, which means an interesting uh, jib, or screecher. trying to get 50 sq ft, but things get a bit floppy, so investing in carbon tape. And 30 more sheets of 1.5 lb epp. Can you say Gorilla glue? Goop waits in the wings.

 

Section is a Stanford derived section.

 

But a single sail on track is beginning to look appealing. As in less frustrating.

 

Other surprises, but anon.

 

Paul

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doing this without epoxy leads me to 6mm! ply.

It needn't you know... Excellent wood boats were built in the aerolite days with thin ply, multiple stringers, multiple skins, local doubling and all the rest of it as structure demanded...

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True. I wanted to go really pointy anyway, single chine flat bottom, the numbers are so much better for a skinny hull with a low WS, and it looks like I can meet weight with stiffer ply, and simpler construction. Since this hull is test a bed more than anything else, I'm thinking 'why not'? Whether she's fast or not, doesn't do the IOR death roll downwind and how easily she gets to a plane, we'll see, but there seem to be some shapes that do interesting things as far as wave making in this neck of the woods at higher SLR's, if my modeling can be believed.

 

The other direction I've been obsessed with has been generally a Formula Board with streamlined ends, which, except for the weight fits in nicely within the 10 sq sail area is happier with 1meter beam rule of thumb (sail area in sq f = width in cm) current with a lot of Formula shapers. But THAT is a big max beam IC, and will require more aircraft style structure to get to weight. Interesting though that some of the wider shapes while high in WS at rest, can be heeled to lower WS than their skinnier brethren for the light stuff. But would you need 8k to get them moving.

 

What does Steve Clark ( The Yankee ) call his shed? The Field of Broken Dreams?

 

 

B)

 

Paul

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I should add that one reason I've been fiddling with an epp wing is that I can go with a section (like 9% up) to go around a fatter mast, do it for a whole lot less $ than a sail, and with any luck it will not self destruct when it hits the water. The stuff is flexible too, and I'm beginning to think that if I'm clever enough, a symmetrical shape can distort into a nice asymmetrical shape under load. And 30 sheets are headed my way.

 

Oh yeah.

 

Paul

 

One of my neighbors, a retired structural engineer, is trying to get me to build the hull out of EPP. Claims I'll hurt myself less when I crash.

Cheeky Devil.

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The Lab of Luxury is on corner of Sleazy Street and the Avenue of Broken Dreams.

 

Just recently I have been playing games with Gorilla Glue.

Mix in water and the stuff foams quite well, about 3x.

Not as brittle as standard 2 part pour in place foam, kind of nifty.

 

I built a sandwich panel using Gorilla Glue as resin.

I did the sample between two sheets of aluminum and clamped it together, I haven't tried bagging it yet.

but it seems that you might be able to tab things together using the stuff, I think you may have to use some pressure or a bit of plastic on the air side.

 

Very light wooden stuff was built before the days of epoxy, you just need bigger gluing surfaces, which takes additional care and patience, but isn't a killer. Spend some quality time with thinned varnish or urethane sealers and make sure you have plenty of ventilation so that the inside can get nice and dry in between baths.

SHC

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I've been using Gorilla glue for the epp- fills nooks and crannies, and when it dries, easy to sand, and has similar flex and tearing strength as the foam, so seams (end butted sheets) are a non issue.

 

Thanks Steve, The bigger glueing area is what I've been planning- looks like clc has some nice light chine log and marine ply (puzzle cut scarf cut) stock- any thoughts on the best chine wood for screwing/nailing and gluing?

 

If I might bug you guys with another question: Gorilla glue under the waterline? Titebond 3? Not as toxic as 3M 5200.

 

The WoodenBoat guys say no, but they leave their boats in the water for weeks at a time I think.

 

Paul

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As JimC suggests, many pretty good boats were built before "real" "waterproof" glues were introduced.

I don't think that on a racing dinghy there is any difference between above and below the waterline.

The key is to manage to keep the wood pretty damn dry, which means putting lots of sealer on the surfaces and maintaining a good finish so that the wood doesn't start wicking up water. So you need to be more thoughtful about how you use the boat and how you care for it. But if it is necessary because it is the only way you can get the job done, then that's the price you pay.

Almost any glue joint will fail if you boil the wood long enough. Gorilla glue may fail sooner than epoxy, but that doesn't mean it isn't durable enough for a dinghy.

Standard dimension lumber for building this kind of stuff is Sitka spruce. It's is not the most durable wood, but is strong and light. Once again, it needs to be sealed and not left top soak in water for 10 months at a time.

Obeche was one of my favorites for years, glues well and is lighter than spruce, but less strong. Not a problem if all you are doing is holding plywood together however.

SHC

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Paul

 

Erich's mast is 100mm diameter at the base, 25mm at the tip. Straight taper. Apparently it was designed so that when fully loaded the tip would be about where a stayed mast tip was. I've left him a message.

 

 

As you know you live in the land of some of the finest wood on the planet. Western red cedar makes a good chine log or sheer clamp - lots of gluing surface for it's weight. If you can pick through some nice Douglas fir you can find stuff that is as light and stronger than Sitka spruce. Bill Buchan used to make Star masts out of it.

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Paul

 

Erich's mast is 100mm diameter at the base, 25mm at the tip. Straight taper. Apparently it was designed so that when fully loaded the tip would be about where a stayed mast tip was. I've left him a message.

 

 

As you know you live in the land of some of the finest wood on the planet. Western red cedar makes a good chine log or sheer clamp - lots of gluing surface for it's weight. If you can pick through some nice Douglas fir you can find stuff that is as light and stronger than Sitka spruce. Bill Buchan used to make Star masts out of it.

 

 

Thanks, Chris, just talked to Ted- he kind of remembered Erich's mast, but he does have the mandrel for it still. So he'll get back to me next week with a quote. I was thinking Carl V. D. Finn sailor. Ted's a canoe sailor. Doh! Anyway, he's also looking up Erich's mast file.

 

I appreciate the reminder about local WRC. I'm up to my elbows in resistance to splitting, fastener holding, bend ability, etc.. In my previous incarnation as piano tuner (42 years) I was heavily immersed in wood (think spruce), but at a level of detail (and industry) where I think I lost touch with the individuality of different woods outside of tone, which rapidly dwindles your horizons.. And that is a black art at best. Especially when you're putting together planks to create a soundboard. So you can understand that when Steve said 'spruce', I was relieved in that at least I have the illusion that I know something about it.

 

And here I'm back to counting growth rings per inch! :D I'd forgotten that Buchan made his Star masts out of the stuff. My dad ( who was an architect who was always building some carvel planked beauty) really like that. He was always checking out different woods at any yard he could find.

 

And considering whether softer woods will compress around a mechanical fastener. Hmmm. Maybe I should smuggle a screw in with me when I'm looking at wood.. I'm sure the yards would love that!

 

Paul

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And considering whether softer woods will compress around a mechanical fastener.

For sure they will... Mechanical fasteners are a sore point with me at the moment because I'm working (very intermittently!) on a 40 year old wood boat that has a lot of glue failure, and whilst the glue failure is resolvable chewed up ends of timber where the glue had failed and mechanical fasteners were doing the work is making me replace timber I'd rather have kept... I think its worth avoiding mechanical fasteners just as much with non epoxy as with epoxy construction. I've used odd scraps of polyurethane foam under cramps when clamping down cedar whilst curing to avoid local compression and I wonder if a similar approach could work if you need to use through fasteners when putting stuff together...

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There are going to be places where clamping is going to be awkward, or I reach a point where a boy can only own so many clamps.

 

I'm going with Titebond 3. It's a good glue, I think, for this application, and the toxicity is low, but it needs pretty high clamping pressure. it also tends to slide a bit over time, so i'm thinking some mechanical fastening would help things, as well has help keep things tight while the glue cures. 6" between clamps seems to be the rule of thumb, so I'm thinking of 12" mechanical spacing, and 12" clamp, which results in the 6 inches. But there are 100 screws to a pound, so screw weight is not that big a deal. Mechanical fastening also helps keep plywood together at the extreme.

 

As much as I like ring nails, I'm going with screws mainly to get easier (progressive?) clamping. You can also theoretically :lol: back a screw out after glue has cured and fill the space with something like Gorrilla Glue or epoxy. In the latest WoodenBoat there is an article about a builder of small speedboats who did that because he couldn't afford screws. But he could afford Weldwood.

 

Are you dealing with old screws or nails?

 

Paul

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You can also theoretically :lol: back a screw out after glue has cured and fill the space with something like Gorrilla Glue or epoxy. Are you dealing with old screws or nails?

Old screws... I normally back out screws when the glue is 90% cured - and use plain steel screws as well which is a saving. Another thought : if you back the screws out you could screw through a batten or something and so not have to worry about local compression of the wood. But there must be people who are far better than I am at this stuff, its just that the boat I'm working on is far lighter built than any UK built one. I'm still mulling over how I'm going to replace some lengths of stringer which have got badly chewed up because I can't get a cramp on those of course. Also worrying about keeping the shape of the boat. If I were energetic I guess I'd build a jig to locate her securely but I'm also short of room.

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The Lab of Luxury is on corner of Sleazy Street and the Avenue of Broken Dreams.

 

Just recently I have been playing games with Gorilla Glue.

Mix in water and the stuff foams quite well, about 3x.

Not as brittle as standard 2 part pour in place foam, kind of nifty.

 

I built a sandwich panel using Gorilla Glue as resin.

I did the sample between two sheets of aluminum and clamped it together, I haven't tried bagging it yet.

but it seems that you might be able to tab things together using the stuff, I think you may have to use some pressure or a bit of plastic on the air side.

 

Very light wooden stuff was built before the days of epoxy, you just need bigger gluing surfaces, which takes additional care and patience, but isn't a killer. Spend some quality time with thinned varnish or urethane sealers and make sure you have plenty of ventilation so that the inside can get nice and dry in between baths.

SHC

 

Made a sandwich panel with white Gorilla Glue- pretty heavy clamping, wood foam wood, sprayed some water on the foam, glued on wood sides, used a squeegie to even out Glue-foamed up so much that everything slid sideways in shear and broke a plastic clamp. Foam all over the place. Does the white foam up more than the brown GG?

 

:)

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Just put glue btw two sheets if ply and let it foam up to a jiged thickness?Otherwise regular pourfoam but it seems like a good way to waste lots of material figuring things out! That's why they mold surfboard blanks I suppose.

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Looking at the tabs on the sheer- they look like they're in front of the mast?

 

Paul

 

Edit- duh, jib track... :o. I am too una rig obsessed

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post-2679-058482200 1303397449_thumb.jpg

post-2679-018517500 1303397491_thumb.jpg

 

Dragonfly IC - nearly finished!

 

 

Cool. Low foredeck, built in mounts for self tacker, stern hung rudder.... and from other pictures clearly a planing machine.

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Just ordered a mast from Ted Van Dusen at www.vandusenracingboats.com . It's based on a mandrel he did for Erich Chase to fabricate an unstayed IC mast. :)

 

I'm going to Bill Hansen for a sail, which will be an una rig.

 

So anyone have any favorites for foils? I'm figuring that as long as I'm using this canoe as a test bed for foils among other things, I'm going to go with a leeboard (only 1 at a time, so I hope I can still come out and play....) to make trying out different boards a bit easier, since I can go with different dimensions without worrying about case size. I've talked to Phil's Foils, but anyone else out there that you guys know about? I don't know that much about importing foils, but if it isn't too out there, or too fiddly, I'm willing to consider it. I know PF are in Canada, but NAFTA helps there. I'm on the Left Coast, Rockies division.

 

Paul

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Dude, you will only be playing with yourself, pretty much. Staying in the same zip code as the rest of the fleet is hard enough without weird leeboard setups, rigs, etc. You have so many variables you will never find out if any of them are fast. Keep something conventional for heaven's sake!

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Really there's only one thing outside the class rules and that's the leeboard. And I would argue that there is nothing more canoe-ish than a leeboard. Killer argument, no?

 

As far as the una rig goes, Phil did good, and my sailing has included the Finn, OK, Lasers, Sol Cat 15, Moth (skiff), Windsurfers, Interclub, Force 5, Banshee, and various catboats. Notice a trend?

 

As for the zip code, it's 99223. So you're right about me sailing by myself. Even other classes as it turns out.. :lol: So it's more about (in my best Barry White) The Love, baby.

 

But if I can make it to a race, I'm hoping she'll at least draw a crowd for measuring.

 

You all can decide whether a leeboard is outside the pale. As long as there's only one on a boat, I don't see a leeboard (or off center centerboard) as a slippery slope to hydrofoils. But I'm blinded by the light, apparently.

 

Paul

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Really there's only one thing outside the class rules and that's the leeboard. And I would argue that there is nothing more canoe-ish than a leeboard. Killer argument, no?

 

As far as the una rig goes, Phil did good, and my sailing has included the Finn, OK, Lasers, Sol Cat 15, Moth (skiff), Windsurfers, Interclub, Force 5, Banshee, and various catboats. Notice a trend?

 

As for the zip code, it's 99223. So you're right about me sailing by myself. Even other classes as it turns out.. :lol: So it's more about (in my best Barry White) The Love, baby.

 

But if I can make it to a race, I'm hoping she'll at least draw a crowd for measuring.

 

You all can decide whether a leeboard is outside the pale. As long as there's only one on a boat, I don't see a leeboard (or off center centerboard) as a slippery slope to hydrofoils. But I'm blinded by the light, apparently.

 

Paul

can you make use of the already existing vanDusen mast built for Erich Chase that Chris has? I believe it is looking for a home.

could save you some cash and lighten Chris' load?

I am probably speaking out of turn. oh dear.

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It's my understanding that the mast belongs to Erich- I haven't heard from Chris or Erich, and as it turns out, my mast need is different enough so it makes sense to do the mast I just ordered.

 

Paul

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A leeboard will be of questionable legality, class rules wise. You are allowed to have the DB/CD 1 meter below the hull.

a straight leeboard will be imersed more than 1 m when the DB is on the lee side when the canoe is heeled

If it is curved toward the centerline plane so that the tip is 1m or less below the hull you may be compliant .

Nat'l Masurer

If you plan on switching DBs port for starboard in a tack, believe me you are already busy enough ,you don't need the added complication.

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But doesn't a curved foil start down the slippery slope of hydrofoils? Or would keeping the length of a straight LB within the radius of 1M below the hull at what, rest? when the hull is heeled (with the radius described by a daggerboard centerlined at 1 M under) to n degrees work? Would the results of modeling be any help in this, or do you need this to be reality based? Static heel?

 

Paul

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Hydrofoils are by name not banned however the application and practical use of them means they really aren't worth playing with on IC's, as Ive said before (maybe not in this thread) if you want to foil by a moth Canoes aren't about that they are different boats which are an absolute pleasure to sail.

 

I would say as long at the centreboard doesn't project more than 1m bellow the hull then a lee-board is ok whatever shape it finishes up isnt an issue, however the exact design would need to be seen so a ruling could be given (drawings sketched or detailed descriptions no need to build and then be told no good, I would hate to see money/time wasted). It possible to be legal with one part of the rules and inadvertently breach another rule.... (Steve and Co did a great job to try and cover loop holes)

 

ICU2

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It depends on the buoyancy of the chine closest to the LB? Loaded w/ my weight opposite at the end of the seat? While the sail drives the lee chine into the aqua? And a buoyant LB resists?

 

This is dynamic hell, in a way, at least. B)

 

Paul

 

But thanks IC, your reply is within the same vein as I'm in. I'm not trying to skirt a rule, just keep a non epoxy hull close to minimum weight.

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I'm not trying to skirt a rule, just keep a non epoxy hull close to minimum weight.

 

Paul,

 

I understand your enthusiasm for quirkiness, I'm just not sure that your justification for a leeboard based on structural weight saving is justified. It might be worth doing a weight estimate of centreboard case vs leeboard fixing arrangement before committing to a leeboard. The loads on an IC are a lot higher than on an open sailing canoe, so the leeboard fixing arrangement will need to be fairly substantial.

 

Mal.

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I'm going to go with a leeboard (only 1 at a time, so I hope I can still come out and play....) to make trying out different boards a bit easier, since I can go with different dimensions without worrying about case size.

I would have thought you'd be about two hundred times better of rigging up a cassette setup so you can plug and play foils in that... The structural implications of leeboards seem pretty complicated to me plus all the hassle of setting things up, surface losses, all the rest of it.

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I think I've found a way to use part of the seat carriage to be part of the leeboard support structure.

 

I may as well divulge that the seat will not slide, but will rotate, which opens up a lot of structural possibilities as well as balance on the hull.

And after watching the vid of the nose plants at the first DC worlds, it seems to me there may be something to being able to fluidly getting weight towards the stern, as well as working through waves. That and I've had a lot of injuries and resultant surgeries that limit some of what I can do.

I'm really not being quirky for it's own sake: centerboard cases are problematic enough with epoxy, and I'm not using epoxy. Building a cassette inside of a CB case without epoxy and carbon is going to get bulky, and probably heavy. The seat will have it's fulcrum at the CB, and a circular support running aft from each of the gunwales. If I join the support to the hull sides, I will have thickness, as well as a bulkhead at that running across a strong back for support. And as Andy was noticing with his una IC he found that he wanted to be close to the centerboard with the seat in some conditions. The LB plus rotating seat allows me the freedom to be on top of the LB in a number of different balance configurations, such as going downwind with the LB swung back a bit for balance and less lift.

 

Granted, I will be chicken hiking, but I will have more control over certain dynamics of the canoe. Less leverage leads to a lighter mast (~10lbs).

Which helps spiral things down elsewhere, which I need, given a non epoxy environment. A shorter seat I hope will lead to handling advantages such as switchingthe tiller extension, and speed in tacking as I presumably won't need to stand up and move the seat during tacks or jibes. it also leads to a lighter seat.

 

I've been doodling a LB as it describes a radius on the leeward side, and if you include buoyancy increase as the hull heals, I'm beginning to wonder how much the LB would go under a line drawn from the end of a 1 meter (from the bottom of the hull)CB at rest. I guess it boils down somewhat to whether the 1 meter measurement point is a line parallel to the beam at 1 meter under the hull, or a point at the midpoint and centerline of the hull. A curved LB to that point would be unfair to the spirit of the rules from my point of view, as it would represent a LOT more span.

 

It may be that the leeboard attachment is a violation of the no attachment to a point outside of the hull. I can see a lot of problems, but an unbroken structure is so much more appealing to me in so many different ways that if what I am doing is considered illegal, i would hope my canoe might be considered a National Canoe. in any event, I live so far from the next Canoe (Chris's) it can hardly matter.

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If your innovative canoe flips and you are righting it say with the LB down, seems like the hull is coming down on top of you as the mast rises. Then will the rotating seat stay put to windward or will it be taken by gravity to leeward or across the deck where you need to hop over it to get it to windward so you can sail? If the LB is high after a flip is it reachable - could be almost 30" up there, 10" above a Nethercott?

 

I am no expert on anything but experience shows I am proficient at flipping canoes.

 

 

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So I just graphed out in a fairly simple form what a LB does as a hull heels, and with a 39" LB on a square chined hull 30" Beam at zero degrees, rotating around the center longitudinal at 15" from the max beam chine that stays at the waterline during heeling, the tip of the LB goes down to the following depth past the 39" line under the hull:

 

The first number is the degree of heel

 

5 = 3/4"

 

10 = 1 1/2"

 

15 = 2 1/4"

 

20 = 3"

 

25 = 2 7/8"

 

After 25 degrees, things get shallower. So, a 36" LB should do the trick, as long as the measurement is a line, and not a point.

 

This does not take into account the hull gaining buoyancy as it heels, which it does with this hull shape, which may mean that the tip of a 29" LB never goes below the 39" depth.

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If your innovative canoe flips and you are righting it say with the LB down, seems like the hull is coming down on top of you as the mast rises. Then will the rotating seat stay put to windward or will it be taken by gravity to leeward or across the deck where you need to hop over it to get it to windward so you can sail? If the LB is high after a flip is it reachable - could be almost 30" up there, 10" above a Nethercott?

 

I am no expert on anything but experience shows I am proficient at flipping canoes.

 

Me too. Even canoes without sails.....

 

When I was a kid, our family had a sailing canoe with one LB. Hull about about 3' wide. Massive amounts of Father installed floation: No worse than a Laser or 5oh. Easier than a Finn.

 

Shock chord to help center seat, will be floating back on from the stern, given my hopping abilities. Flotation in the mast and or sail. The way that my boats have never stayed put the same way to the wind that they capsized when they come up, its' kind of hard to say which side of the hull I'd like it to be. ESP after a death roll, which was what I specialized in with my old Nethercott the most, by far.

 

Paul

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I'd worry about the seat rotating down at speed onto your head...

 

It is very easy to make a non-epoxy cb cassete with two chunks of 3/8" or 5/16" Delrin and some 10-32 allthread at the corners. Cut inside the scribed foil profile with a jigsaw and sand to fit with the actual board, then bolt it together and lock off with nylock nuts. Little G10 plates to keep it in the boat. Great action-Smooooth.

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Ps I think it states the db can't project more than one meter from the bottom of the hull; there is no specified angle of heel, so you should be Ok. But I need to review the rule.

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centerboard cases are problematic enough with epoxy, and I'm not using epoxy. Building a cassette inside of a CB case without epoxy and carbon is going to get bulky, and probably heavy.

I dunno, it still feels to me as if you are creating a large problem in order to avoid a small problem... You don't need to build a cassette inside the case at all.

This is what I'd do...

Just build a simple rectangular daggercase, which is something thousands of homebuilders did successfully with aerolite in the 60s and 70s, and have the outer skin overlap it say half an inch by 6mm or 8mm thick front and back - make the skin double thickness for a reasonable overlap of the board Get the foilbuilder to build the cassette with the foil (HD foam, glass for the cassette and an outer cover) and shape it so that it fits flush with the hull outer skin resting fore and aft on the skin - a tenon really. Captive bolts to screw on a capping piece, and there you go - something like this...

post-60-078739900 1303848542_thumb.gif

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