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#301 Phil S

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Posted 03 April 2008 - 03:08 AM

It depends on how you see the ballot and Sailing committee decision.

The ballot wording was specifically to replace the existing rules with the DC rules and to leave the AC unchanged.
We did not vote to retain the one design as a class, we voted to effectively amalgamate the one design nethercott hulls into the development rules class. The one design rules could have been merged with the AC rules where they will be still needed. The change eventuated as the majority of the sailing committee tried to appease a minority of people who did not want a change.

The result has been the retention of three classes when we voted for a reduction to two.

There is talk about combined fleets with special trophy for one design boats but in reality the specific wording of the SC comprimise decision is to allow three separate fleets, and while in many countries where the one designs remain the majority (all except US), it is easy to see how the minority new rule boats will be sidelined, or even excluded from winning class events. So people may not be so keen to build new rules boats in these countries.

The canoe fleet world wide is too small for a three way split. 40 odd boats at the recent World Champs split three ways makes for poor fleet racing. A 15 odd boat national fleets split three ways is a joke.

I truely hope that people build new rule boats, but I have been sailing mine for nearly two years and have only got to race against any fleet of other canoes at 4 events, even though I am in Australias biggest city. My boat now is available for any enthusiast as a very low price.

I could be tempted to make another one in the future if the committee (minority) is right and I am wrong and there is a resurgence in numbers. I hope so, the people actually sailing in the class are great and ride is worth it.

#302 rocknodster

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Posted 03 April 2008 - 05:06 AM

Phil, don't run away now - you did all that trailblazing work and now I have an IC (DC), Geoff H's is going strong, Haydens is in build (though no pics yet), Geoff C and Rob W are building light Nethercotts, theres a rumuor of String Theory interest in WA. The Aus nationals in October could be where we see more IC's than OD's.

Who's going to win the first Aus IC Nationals of the 'new era'? ICYM struggled in trying conditions in the log (pre rig changes) in 2007, can you punt the log to the front (or will it have a new pilot?). Can ICU2 take honours in a new boat, or his old boat??? Is there a dark horse out there who will lift the crown? Will I, with my new bendier c-tech mast be near the front? Will the OD's spank us all? :(

Exciting times to be in an IC, great time to get involved in this class as we look to defending some prestigious silverware in 2011.

#303 IC youth movement

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Posted 03 April 2008 - 06:02 AM

Really all this changes is that it lays out how worlds will be run. If you want to win a worlds you show up in a new rules boat. If you want to be competitive internationally you want a new boat. All this does is it lets Sweden continue doing what its doing in its own country and gives them a name for it. I personally think they are wrong to not embrace the change, but hey thats their call and they can do what ever they want. Everywhere else in the world things move ahead as planned. The US nationals were already won by a new rules boat last year so we've already made that call. The overwhelming support of the change in the UK and Aus would indicate to me that their going to embrace the new rules rapidly. Who knows what happens in Germany.

The new rules have sparked a flurry of interest and activity in three countries. I realize that the political process was pretty ugly, but we've gotten through that and thank you guys on the committee for your work, it is much appreciated.

So now I think it is back to our regularly scheduled programing. The future is bright for the class as a whole.

The movement continues. Who wants in?

#304 ICU2

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Posted 03 April 2008 - 07:23 AM

Phil, don't run away now - you did all that trailblazing work and now I have an IC (DC), Geoff H's is going strong, Haydens is in build (though no pics yet), Geoff C and Rob W are building light Nethercotts, theres a rumuor of String Theory interest in WA. The Aus nationals in October could be where we see more IC's than OD's.

Who's going to win the first Aus IC Nationals of the 'new era'? ICYM struggled in trying conditions in the log (pre rig changes) in 2007, can you punt the log to the front (or will it have a new pilot?). Can ICU2 take honours in a new boat, or his old boat??? Is there a dark horse out there who will lift the crown? Will I, with my new bendier c-tech mast be near the front? Will the OD's spank us all? :(

Exciting times to be in an IC, great time to get involved in this class as we look to defending some prestigious silverware in 2011.



Ok! it didn't/isnt happening unless there is a photo. It is happening and pics will come once there is a nice shinny product to see, at the moment its a boring timber mold alomst done and who wants to see a dull boring male mold (id rather see the shinny flash product). Anyway internals are made waiting for the shell and I was hoping to have the boat ready to paint by now, but a paying job got in the way. The build is back on the top of the list so things will happen again over the next week or so, stay tuned.

Who knows I just might get the first new rules IC on the water :D, as those built to date have been DC's.

ICU2

#305 seabag

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Posted 03 April 2008 - 10:53 AM

It depends on how you see the ballot and Sailing committee decision.

The ballot wording was specifically to replace the existing rules with the DC rules and to leave the AC unchanged.
We did not vote to retain the one design as a class, we voted to effectively amalgamate the one design nethercott hulls into the development rules class. The one design rules could have been merged with the AC rules where they will be still needed. The change eventuated as the majority of the sailing committee tried to appease a minority of people who did not want a change.


May I remind you that rules change procedure require unanimous ccommmittee consent. This has been posted for years and no one has complained. The rules have indeed done the replacement. It does continue one design rules for the older boats. Whether to retain them or toss them was the question. Passing the change meant compromise.

xin loi

#306 ic blast

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Posted 03 April 2008 - 08:10 PM

Ok! it didn't/isnt happening unless there is a photo. It is happening and pics will come once there is a nice shinny product to see, at the moment its a boring timber mold alomst done and who wants to see a dull boring male mold (id rather see the shinny flash product). Anyway internals are made waiting for the shell and I was hoping to have the boat ready to paint by now, but a paying job got in the way. The build is back on the top of the list so things will happen again over the next week or so, stay tuned.

Who knows I just might get the first new rules IC on the water :D, as those built to date have been DC's.

ICU2


do I smell a challenge to get the worlds first new rules ic on the water sailing!?

Great stuff! It seems the words mean less than the intent of the sailors making it happen.

Phil, your 'trail blazing' with the tortured ply got me enthused to build my own boat - cheers - so stick around and take it to the next level.

#307 John K

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Posted 14 April 2008 - 02:41 AM

The news is in!

The ICF (International Canoe Federation) Congress has accepted the recommendations of the ICF Sailing Committee, and the class has adopted the "DC" as the new IC Rule. A very big thank you to Steve Clark for proposing & refining the rule, to the pioneers who believed enough in the concept to build boats built to the new rule & to everyone who supported the idea. There is still much work to do, but this is a positive step for the class.

Thank you

John Kells
USA-244 "Mayhem"
US Class Secretary



It is good to own an IC again!

#308 rocknodster

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Posted 28 April 2008 - 10:35 PM

Okay, I've just rubbed back and repainted AUS26 (formerly USA239) 'Trouser Friendly Kiss', and she's looking nice and slick in Grey (might have overdone the deck grip a little, but I skimped a while back with my first Nethercott IC and I'm not making that mistake again). New mast has arrived aswell, C-tech have turned out a bloody nice product at a brilliant price and the stick is very light too - can't wait to get some sails cut for it and hit the water real soon.

It will be out on the water at the Sauna Sail in June, so PM me if you're interested in taking an IC for a testflight ;)

#309 rocknodster

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Posted 12 May 2008 - 11:17 AM

Highlights of the 2008 World Championships and bits of the IC Promotional DVD will be screened on 'On the Water' over the next 2 weeks on Channel 31 (highlights on YouTube soon). Please check it out:
Show Times

Melbourne - Thursdays 7:30 PM
Adelaide - Tuesdays 8 PM
Brisbane - Mondays 8:30 PM
Sydney - Fridays 7:30 PM
Perth - Thursdays 8 PM and Tuesdays 4;30 PM

As well as their website On the Water

Hi Christian,
If you tell everyone to watch the show over the next week or two they will see it. Different states are on different episodes. I'm not sure how they managed that, when it all rolled out in the same week, but anyway.

Cheers

Caveman



#310 ic blast

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Posted 16 May 2008 - 03:15 AM

A question to the purest canoe sailors here: Is putting a 2-flat panel foredect (peaking at the centreline), as opposed to a convex unit too blasphemous??

are there implications that I'm not seeing for jib sheeting?

Cheers

AP

#311 c maas

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Posted 16 May 2008 - 03:28 AM

A question to the purest canoe sailors here: Is putting a 2-flat panel foredect (peaking at the centreline), as opposed to a convex unit too blasphemous??

are there implications that I'm not seeing for jib sheeting?

Cheers

AP


I am definitely not the purest canoe sailor here but I'd say that's a fine idea.
It seems to me that innovation should be encouraged now that the IC is a development class again. And remember: It's all been done before.

#312 JimC

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Posted 16 May 2008 - 06:40 AM

are there implications that I'm not seeing for jib sheeting?

I'm about as impure Canoe sailor as they come I suppose and I dunno about jib sheeting, but for boats with varnished wood decks I think the main implication is that you are committing yourself to a butt joint between two bits of ply in about the single most visible part of the boat!

Overall it seems to me you are adding an extra bit of work in the contruction for no great benefit. Performance wise I should think there's very little difference. I suppose the curved deck might be marginally smoother for air flow but I can't believe its anything measurable compared to the drag horrors at the end of the foredeck. Or have I missed something?

#313 Speng

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Posted 17 May 2008 - 06:52 PM

let me ask the semi-sacreligous question: When's somebody going to put a huge stunner on a new rules IC? AC DC? Yeah Baby!!

#314 JimC

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Posted 17 May 2008 - 08:39 PM

When's somebody going to put a huge stunner on a new rules IC?

Not the point. And big sails are so very 1990s.

#315 Steve Clark

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Posted 17 May 2008 - 10:37 PM

In other news:
Panels for Roger Regitz's new boat are back from the laser cutter.
Will be folded up this month.
Attached File  Flat_IC_Bow.JPG   20.69K   72 downloads
Bow is cribbed from Phil Stevenson's Hollow Log and the stern is something like Chris Maas' String Theory.
Stuff in the middle takes something from the Morrison and Kells.
Attached File  Flat_IC_stern.JPG   85.68K   102 downloads
Should look about 4 times bigger than this when done.
Attached File  second_string.jpg   204.86K   86 downloads
SHC

#316 rocknodster

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Posted 17 May 2008 - 10:58 PM

Cool, can't wait to see that fully rigged!

#317 atypicalguy

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Posted 18 May 2008 - 09:36 PM

In other news:
Panels for Roger Regitz's new boat are back from the laser cutter.
Will be folded up this month.
Attached File  Flat_IC_Bow.JPG   20.69K   72 downloads
Bow is cribbed from Phil Stevenson's Hollow Log and the stern is something like Chris Maas' String Theory.
Stuff in the middle takes something from the Morrison and Kells.
Attached File  Flat_IC_stern.JPG   85.68K   102 downloads
Should look about 4 times bigger than this when done.
Attached File  second_string.jpg   204.86K   86 downloads
SHC


Hey Steve was that the same laser that did JK's mold bits? I haven't found anyone out West who does this sort of stuff - need to get some pieces cut for a Moth tool.

#318 John K

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Posted 18 May 2008 - 10:35 PM

In other news:
Panels for Roger Regitz's new boat are back from the laser cutter.
Will be folded up this month.
Attached File  Flat_IC_Bow.JPG   20.69K   72 downloads
Bow is cribbed from Phil Stevenson's Hollow Log and the stern is something like Chris Maas' String Theory.
Stuff in the middle takes something from the Morrison and Kells.
Attached File  Flat_IC_stern.JPG   85.68K   102 downloads
Should look about 4 times bigger than this when done.
Attached File  second_string.jpg   204.86K   86 downloads
SHC


Steve,

I'm assuming that you are using 3mm ply for the hull skins, will you be using internal frames with a carbon skin similar to Wonk, or will you be looking to a modify the structure based upon past experience?

I'm looking forward to seeing photo's as things progress.

Best

JK

#319 Phil S

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Posted 18 May 2008 - 11:23 PM

Stressed ply canoe building?

For the uninitiated this is the next step to change the odd shaped bit of flat ply to the hull shape like Steve's blue model. taken from the How to build a Holllow Log article:

Use lots of tape on the outside and some pieces of copper wire between pairs of 2mm holes drilled 15mm back from the edge. Push the ends through from the inside and tighten them by twisting the ends together on the outside. Then push the inside loop down as flush with the ply as possible.

Use masking tape across the outside of the ply to close up the gaps and to seal against epoxy leakage, and form the chines and keel seams. Start at the thin end of each seam and work your way to the ends. Make sure the joint is pulled in tight, and keep checking that the line is fair and true, and that the two side pieces are level at the bow, not one forward of the other.

When taping is complete set the hull upright on a trestle at each end and adjust the width with ties, sticks and tape so that the widths are:


Station Width
bow 880mm 2000 from bow 1250mm
3500 from bow 1070mm
(Note the bow is not wired or taped together but left out flat to get max round in the bow area. A tight rope from bow to stern will help bend the hull and make the cross eections flatter fore a better rounded bottom shape.)
The seams are taped inside and out with carbon tapes. You can buy carbon in tapes but it is a normally a heavy grade. Alternatively cut carbon cloth (about 200gsm) into 50mm 60mm wide strips. If the cloth is not a square weave, cut it with the major fibres across the strips. Use one layers inside and one outside. Do not seam the front half M or the back M until the bow is tied together and the hull is pulled into final width.
Set the hull up so that it is supported well and will not wobble around while you work. Make sure that it is symmetrical and not twisted.


(Bold bits have been added,as there has been some misunderstanding?)

Anyone inspired should stay in touch. Steve will have a CAD file available soon so you can get your ply cut precisely to shape.

Phil S

#320 IC Nutter

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Posted 19 May 2008 - 02:18 AM

In other news:
Panels for Roger Regitz's new boat are back from the laser cutter.
Will be folded up this month.
Attached File  Flat_IC_stern.JPG   85.68K   102 downloads
SHC


Who's idea is the jigsaw puzzle panel joins? I haven't seen that done before.

#321 Phil S

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Posted 19 May 2008 - 02:20 AM

Steve assures us that it works. I hope it lets the panel bend enough mid ships.

#322 John K

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Posted 19 May 2008 - 02:41 AM

Who's idea is the jigsaw puzzle panel joins? I haven't seen that done before.



Chesapeake Light Craft, a manufacturer of plywood stitch & glue sea kayak kits in Annapolis replaced scarf joints with puzzle piece joints in their new designs sometime last year. For sea kayak kits, it takes the error out of lining up the hull panels, as the CNC milled joint will maintain the alignment.

Im not at all sure that I would recommend it if you were to cut out your parts by hand.

Check out www.clcboats.com

Best

John K.

IC USA-244

#323 Phil S

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Posted 19 May 2008 - 03:02 AM

John,
There does not appear to be very much curvature in those Kayaks. Certainly no where near what is needed to get a good rounded shape for the sailing canoe.
Phil S
see:
http://www.flickr.co...57601502156525/
for Hollow Log construction.
Particularly this one which shows how curved it needs to be:
http://www.flickr.co...57601502156525/

#324 John K

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Posted 19 May 2008 - 03:17 AM

John,
There does not appear to be very much curvature in those Kayaks. Certainly no where near what is needed to get a good rounded shape for the sailing canoe.
Phil S
see:
http://www.flickr.co...57601502156525/
for Hollow Log construction.
Particularly this one which shows how curved it needs to be:
http://www.flickr.co...57601502156525/


Phil,

For Steve & Roger's sake, I hope that it does work, but I suspect that some glass or carbon over the joint should do the trick without creating hard spots. For me, I just have a few repairs to make to Mayhem to get the sailing season started. I'm a few years away from my next build, that or I need an insulated garage that will keep me occupied during the long winter months. Building during the summer is not compatible with sailing.

Best

John

#325 atypicalguy

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Posted 19 May 2008 - 04:21 AM

John,
There does not appear to be very much curvature in those Kayaks. Certainly no where near what is needed to get a good rounded shape for the sailing canoe.
Phil S
see:
http://www.flickr.co...57601502156525/
for Hollow Log construction.
Particularly this one which shows how curved it needs to be:
http://www.flickr.co...57601502156525/


I'm sure Steve will share details of technical problems (if any) with interested parties who inquire.

#326 JimC

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Posted 19 May 2008 - 06:32 AM

I hope that it does work, but I suspect that some glass or carbon over the joint should do the trick without creating hard spots.

I have no opinion on how well it will work, but I can see what a huge advantage it must be coming to laser cut ply... I have bad memories both of my father buying a kit boat with ready cut scarfed ply edges thirty five years ago, and also of my own first attempt to make a ply scarf joint just a few months ago... The potential seems tremendous. I wonder about having reinforcement only on the inside of the join as you fold up the boat, and also of whether frames should be located over the joins to encourage the shape to stay as intended? It would need some juggling so frames were in the right places which would probabl up the number of sheets of ply though.

#327 Steve Clark

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Posted 01 June 2008 - 08:20 PM

Here at the Farm we obey the Geneva Convention
We don't torture plywood, but we do ask it hard questions.
Attached File  rolled_up_fixed.JPG   185.13K   196 downloads
I hope Phil aproves
Attached File  Rolled_up_2_edited.JPG   220.43K   198 downloads
Pretty much the way I thought it would look like.
Attached File  upside_down_2.JPG   152.99K   190 downloads
But making something look boatlike has never been the hard part for me, getting all the pieces inside to make it strong enough to leap out of waves at 15 knots is the beauty part.
SHC

#328 gui

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Posted 02 June 2008 - 02:48 AM

Here at the Farm we obey the Geneva Convention
We don't torture plywood, but we do ask it hard questions.
Attached File  rolled_up_fixed.JPG   185.13K   196 downloads
I hope Phil aproves
Attached File  Rolled_up_2_edited.JPG   220.43K   198 downloads
Pretty much the way I thought it would look like.
Attached File  upside_down_2.JPG   152.99K   190 downloads
But making something look boatlike has never been the hard part for me, getting all the pieces inside to make it strong enough to leap out of waves at 15 knots is the beauty part.
SHC


Looks pretty good Steve ... How much was the laser cut?

#329 Matt D

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Posted 02 June 2008 - 01:09 PM

Wow, that's really cool.

How hard is it to do that? How many hulls would your average sailer have to ruing in attempt before success?

Do you have a laser cutter on the Farm? I have to come see your "sheds" some day, the variety of boats that come out of them are incredible.

#330 Hannes

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Posted 02 June 2008 - 01:45 PM

How did you do the transition from the chine to rounded without breaking / splitting the plywood?

Thanks

Hannes

#331 Steve Clark

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Posted 02 June 2008 - 03:58 PM

No Laser cutter here, but there are about 4 within 1/2 hour.
They charge by the inch of cutting, and Bud hasn't sent me a bill yet, and I also cut two sliding seat kits at the same time.
At the ends of the chine and keel darts, I put a hole as a stress rerliever. This is tha traditional way of stopping crack propigation, and it worked well.
Attached File  Stress_releif.jpg   86.49K   50 downloads
I also had Bud cut all the lacing holes so they were as consistant as I could get them. I will delete about half of these before I do it again and also move them closer to the edge.
Sliding seat: Having an accurate way of cutting out lots of pieces allows you to build complex things really easily.
Attached File  seat_construction.jpg   151.33K   57 downloads
This is just like a model airplane wing, and the finishes at 7.5 kg
Attached File  P6010122.JPG   269.21K   43 downloads
Attached File  P6010123.JPG   221.25K   39 downloads
Pretty cool.
Come down to the 14NAs and we will let you tour the Labs of Luxury.
SHC

#332 atypicalguy

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Posted 03 June 2008 - 02:49 AM

Seriously accessible building techniques.

Go the 7.5kg laser cut ply seat. That's an impressive number. Might could cut the internals from sandwich and use ply for the surfaces to save a bit more if needed to hit 50?

Did you cut carriage parts also?

Anyway it's looking fast and fun. Kudos.

K

#333 stinky

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Posted 03 June 2008 - 05:04 AM

would it make more sense to the keep the internals ply and just chop the 3 big pieces out of composite? ....if one was to head in that directon.

#334 JimC

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Posted 03 June 2008 - 06:25 AM

would it make more sense to the keep the internals ply and just chop the 3 big pieces out of composite? ....if one was to head in that directon.

Steve would be better at this stuff than me, but I think if you were changing the materials you'd change the entire construction, not just substitute foam panels for ply. I imagine for a foam/carbon seat you wouldn't use nearly so many ribs but have more substantial ones because of the different properties of the material.

Incidentally, is it just the angles/my eyes, or is that a very low rocker boat Steve? To my eyes the rocker looks less than Josie or String Theory

#335 rocknodster

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Posted 03 June 2008 - 07:37 AM

Incidentally, is it just the angles/my eyes, or is that a very low rocker boat Steve? To my eyes the rocker looks less than Josie or String Theory


I reckon your right Jim, I just had a look at my 'josie' hull. and I reckon it has more rocker than the boat above has. Though it might pull together more, mightn't it?

#336 aus_stevo

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Posted 03 June 2008 - 07:54 AM

pulling it together more would flatten it further, need to spread gunwhales to get extra rocker.

having been involved in a few of these stressed ply boats with phil over the years it looks to me that the boat needed more spread whent eh seams were laminated to push more curvature into it, this would also mean that the transition are eround the end of the chine would be smoother. no doubt phils would be here later to comment further

#337 Steve Clark

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Posted 03 June 2008 - 11:19 AM

Most of the seats I have built that weighed less than 7.5 kg have broken one way or another. These have been fairly thoughtful carbon foam parts.
The weight difference between 4mm plywood and a nominal ( 200g/m^2 -6mm H-80 foam-200g/m^2) carbon panel is about 200 g/m^2. So for little pieces plywood is a very efficient material. Just like Meade and Jan have always said.
Where cored composites score big is in stiffness not in weight.
But the point of this effort is to use the internal structure to self form the curves that are needed to make the piece and thus eliminate the need for building fixtures and molds.
If one is designing something to be seriously exportable, and capable of being built without many jugs and fixtures, a relatively complex "egg crate" cut by accurate machinery ( which also seems fairly common) seems like a good deal.
If the cutter can't be found locally, the flat pack can be shipped UPS.
I haven't done a seat carriage because the beams of the various designs is different, and building the carriage using the seat as the fixture is pretty easy and a reliable way to make sure everything fits and works.

The rocker of GER 78 in the should end up in the 60mm range. It looks worse in the photos because the hull is draped over a couple of saw horses. Even so this is about 60% as much as Josie and about 15mm less than String Theory. The photos showed just the first pull at rolling the boat up. No one should panic and or make any declarations yet.
SHC

#338 Phil S

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Posted 03 June 2008 - 11:23 AM

Jim,
I have already had some discussion by email with Steve on spread and seams. Andrew might be on track.
Christain,
This boat has similar ply shapes as the Hollow Log except down the back, where it is wider. So the spring should be similar to the Log which is a lot less than Josie, especially aft where there is no keel shaping so it is straight.
Maybe the way I could catch Steve downwind at McCrae influenced his ideas.

#339 rocknodster

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Posted 03 June 2008 - 11:45 AM

This boat has similar ply shapes as the Hollow Log except down the back, where it is wider. So the spring should be similar to the Log which is a lot less than Josie, especially aft where there is no keel shaping so it is straight.
Maybe the way I could catch Steve downwind at McCrae influenced his ideas.


No doubting the Log is quick off the wind, Mannering Park and the Brass Monkey showed me that. I don't know enough about rocker and spring and their flow on effects in long skinny high performance dinghies but I look forward to seeing these boats on the water and racing against them (and maybe some regular racing against the log.....?)

#340 Steve Clark

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Posted 03 June 2008 - 12:18 PM

I think the 20+ kg delta between PS and SC had something to do with it as well.
In any event the Log was very impressive.
Trying to capture some of that ability to slide along, put a more conventional power plant on it.
I also think that having some beam aft helps the skipper particularly in the manouverig portions of the program. Wyat I think is critical there, and what Chris really had right, was to leep the chines high and maintain a lot of athwartship curvature in the hull aft.
It's fun to try to figure out what the correct balance is.
Just so you jnow, I haverelaxed the hull and am going to be taping the outside of the keel forward and the first half of the chine,
This will drive a bit more round into the bow.
SHC

#341 Phil S

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Posted 03 June 2008 - 09:43 PM

Be patient folks.
What Steve is doing is creating a very accessible new version of one of his favourite boats, based on his and a few other people's modern ideas and many years of experience as to what works. Construction is still somewhat in the try and test stage.
When he is finished his work and documentation, everyone who is interetsed will have access to the design for a great ride.
And I am sure he also has other projects running so hang in there and follow the story.

#342 MT Sailor

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Posted 03 June 2008 - 09:58 PM

When he is finished his work and documentation, everyone who is interetsed will have access to the design for a great ride.
And I am sure he also has other projects running so hang in there and follow the story.

And that is why Steve is a hero. A great yachtsman who cares to get others involved.

I'm helping my brother build a ply-moth right now and we've already stole the idea of the puzzle scarp joint and it worked awsome.

Steve, is that fishing monofilament you're using to lace up the hull?

#343 JimC

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Posted 03 June 2008 - 10:27 PM

But the point of this effort is to use the internal structure to self form the curves that are needed to make the piece and thus eliminate the need for building fixtures and molds.

Which is a very good point indeed, speaking as someone who's continuing to use a ratty 10.5 kg seat as I'm not brave enough to make a new one. I reckon a carriage is pretty striaghtforward by comparison, especially if you don't stuff up the design [embarrassed grin].

#344 Godfrey Bigot

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Posted 04 June 2008 - 02:41 AM

What Steve is doing is creating a very accessible new version of one of his favourite boats, based on his and a few other people's modern ideas and many years of experience as to what works. Construction is still somewhat in the try and test stage.
When he is finished his work and documentation, everyone who is interetsed will have access to the design for a great ride.


Are there any other free DC plans out there that dont use this origami style of boatbuilding?

#345 rocknodster

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Posted 04 June 2008 - 02:50 AM

Are there any other free DC plans out there that dont use this origami style of boatbuilding?


http://www.internati...pments/13267/0/

Plus directly contacting Chris Maas, and John Kells.....

#346 atypicalguy

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Posted 04 June 2008 - 03:23 AM

Which is a very good point indeed, speaking as someone who's continuing to use a ratty 10.5 kg seat as I'm not brave enough to make a new one. I reckon a carriage is pretty striaghtforward by comparison, especially if you don't stuff up the design [embarrassed grin].


Luv the no jig, no-mold seat program

I'm far from expert in such matters, but when I run some numbers on a 5lb/ft3, 0.25" foam cored panel at 40% fiber content by weight (infused) and assume 4mm Okume is 16lb/sheet (without epoxy sealer) it looks like you save 500-800gm/yd2 with a sandwich. My numbers are probably off...I did use the nifty Proset laminate weight calculator thingy and account for a layer of carbon on each side etc. Seems like maybe you could have a 6.5kg seat with nice ply on the outside to take the lumps, but a seat is probably a stupid place to try to save that kilo.

#347 Norm

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Posted 04 June 2008 - 10:19 AM

This great to watch, another thread asks what is the next big thing?

I reckon it is flat packed boat with some prefabbed parts such as centreboard case, rudder, etc.

#348 ICU2

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Posted 04 June 2008 - 12:32 PM

Incidentally, is it just the angles/my eyes, or is that a very low rocker boat Steve? To my eyes the rocker looks less than Josie or String Theory


Photos can be missleading. I just had a look at the mold im building, if I was to take photos from 5 selected angles I would be able to show you 5 different persective to the amount of rocker when projected onto a 2D plane i.e. a photo. I agree it looks like bugger all rocker, I've sailed Josie simply awesome Steve has has time to improve her Roger is set to have a great boat Im sure.

ICU2

#349 TeamFugu

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Posted 04 June 2008 - 12:39 PM

Luv the no jig, no-mold seat program

I'm far from expert in such matters, but when I run some numbers on a 5lb/ft3, 0.25" foam cored panel at 40% fiber content by weight (infused) and assume 4mm Okume is 16lb/sheet (without epoxy sealer) it looks like you save 500-800gm/yd2 with a sandwich. My numbers are probably off...I did use the nifty Proset laminate weight calculator thingy and account for a layer of carbon on each side etc. Seems like maybe you could have a 6.5kg seat with nice ply on the outside to take the lumps, but a seat is probably a stupid place to try to save that kilo.

You'd probably be better off using Kevlar cloth for the skin on a foam cored seat than okume. It will have a much better puncture resistance and maybe a bit lighter. Down side is the cost and lack of user freindliness. Carbon is a wonderous product but should never be thought of as a skin material.

#350 RogerIC

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Posted 04 June 2008 - 01:04 PM

Steve has has time to improve her Roger is set to have a great boat Im sure.

ICU2


that are my thoughts too and i'm looking forward to race GER 78 against you in travemuende 2011.

Photos can be missleading. I just had a look at the mold im building, if I was to take photos from 5 selected angles


by the way i think we all would love to see some pics of your activities ....


Roger
still IC GER 68

#351 Steve Clark

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Posted 04 June 2008 - 01:20 PM

Atypicalkarl:
It's "Love" love. Don't let the southern California sun rot set in. It's only an extra key stroke and it maintains standards.
And as man has often found when lost in the wilderness, it's all about standards; dressing for dinner and all that.
Pukka Dude Pukka.
That being said, my book has 4mm okoume ply at 12 lbs per sheet. which pretty much matches your carbon foam panel and has the hidden advantages of coming off the truck ready to use, and cutting really well with a laser.
FUGU:
I avoid Kevlar next to the skin whenever possible.
The seat has significant compression components, making Kevlar a bad choice.
If you are going to get down to the weights we are talking about, you simply have to use carbon as the skin layers.
The good news is that the stuff is stiff enough that is prevents a lot of the core denting that would happen if you used glass.

I have to get Penfeild's A Cat out of here and also get the Wonk repaired in time for Ottawa. Some other secret stuff is also on the pile.
SHC

#352 TeamFugu

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Posted 04 June 2008 - 01:25 PM

Steve
For now I'll take your word for it but that doesn't quite square with my limited experience. As long as the foam can keep the carbon from deflecting too much and will transfer the load over a wide area, it probably would work. Kevlar is messy stuff but it also transers the load in the skin better than carbon as well as having a better puncutre resistance.

#353 atypicalguy

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Posted 05 June 2008 - 04:58 AM

Atypicalkarl:
It's "Love" love. Don't let the southern California sun rot set in. It's only an extra key stroke and it maintains standards.
And as man has often found when lost in the wilderness, it's all about standards; dressing for dinner and all that.
Pukka Dude Pukka.
That being said, my book has 4mm okoume ply at 12 lbs per sheet. which pretty much matches your carbon foam panel and has the hidden advantages of coming off the truck ready to use, and cutting really well with a laser.

Firmly ensconced in the Renaissance...

Whosoever is delighted in solitude is either a wild beast or a god - Aristotle

By all means, dress for dinner, even if your only guest is a volleyball.

But on that note, it's "Sahib" - only one extra keystroke, and it maintains standards.

#354 skiffboy

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Posted 05 June 2008 - 10:29 AM

When I tried to get a hull kit laser cut a few years ago they refused to take the job based on the fumes created being too noxious. Also they couldn't garuntee the tolerances on the edges because of smoulder etc. Although the panels were allerady laminated, it was apparnetly the ply which was the issue. You haven't had that problem in getting these kits cut?

#355 Steve Clark

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Posted 05 June 2008 - 12:42 PM

Precision Laser, the company I have been using has had no trouble cutting plywood. Maybe they are unusual.
I think cutting cored composite panels might be a challenge because the materials in the cross section have such different properties. The only composites I have had cut were on a CNC router.
A waterjet would probably work as well.
SHC

#356 Steve Clark

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Posted 05 June 2008 - 03:13 PM

Some more images of GER 78 in development.
Attached File  20080605_01.JPG   165.11K   162 downloads
Attached File  20080605_02.JPG   121.9K   153 downloads
Things going pretty well, except that right under the forefoot the plywood made some decisions that were not it its own best self interest.
This required the spontaneous addition of two additional darts and will require modest rhinoplasty.
SHC

#357 Steve Clark

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Posted 05 June 2008 - 03:42 PM

Attached File  20080605_08.JPG   205.19K   183 downloads
The next bit is to stabilize things straight and untwisted, Which is pretty good so far.Attached File  20080605_06.JPG   182K   163 downloads
Attached File  20080605_07.JPG   197.76K   138 downloads
Make sure that the rise of floor and beams all are legal, which also has been looking pretty good.
I will then take a step into the unknown.
The problem with tortured ply boats, in my opinion, is that there is an inherent conflict between the thickness of ply you can distort into shape and the thickness of skin you want for panel stiffness. Phil and many others solve this by fitting internal bulkheads to reduce the unsupported spans to something that the plywood can handle. Phil uses Styrofoam with a bit of carbon wrapped around it to form ring frames. This has some problems from my perspective, First Styrofoam is a pretty lousy structural material and second it has about 2% porosity bu volume. So it makes a great sponge and can hold a whole lot of water.
I propose to vacuum bag 6mm H-80 Divinycell and 70 g/m^2 Kevlar into the inside of hull skin between the chines and running forward to the stem. This will make the parts of the boat that hits the water beau coup stiff for about 2kg of weight. the risk is getting a good vacuum and knowing that the boat is the right shape. some of these things require opposite solutions, so I am having to feel my way forward. But the result, If I can pull it off, will be super impressive.
Film at 11.
SHC

#358 Mothboy

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Posted 05 June 2008 - 03:47 PM

I'm going to put it out there - this boat is. Cool. As. Fuck.

#359 TeamFugu

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Posted 05 June 2008 - 03:52 PM

FWIW, using foam bulkheads is a plus when you collide with something between the stations. If the station is very rigid, then the skin has a greater chance of failing catistrophicaly by sheering where a foam bulkead will deform allowing the skin to flex more. It seems everything has its plus and minus. Too bad it is hard to find something that comes up all plusses.

But then this is a mute point if you can keep from hitting things. A very good idea no matter what you choose.

#360 RogerIC

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Posted 05 June 2008 - 04:00 PM

Some more images of GER 78 in development.
Attached File  20080605_02.JPG   121.9K   153 downloads


If i compare this with the picture of the second string model im realy impressed about how near you have managed to hit the target !

Attached File  second_string_stern.JPG   132.5K   33 downloads

Roger
(still) IC GER 68

#361 ADK

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Posted 05 June 2008 - 05:31 PM

Nice work Steve! That's one good looking boat.

It's really cool to see all this effort being put into making a boat that's fast and competitive while keeping the building techniques and budget at a more approachable level for the DIY type.

#362 Liquid

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Posted 05 June 2008 - 06:30 PM

First Styrofoam is a pretty lousy structural material and second it has about 2% porosity bu volume. So it makes a great sponge and can hold a whole lot of water.


Styrofoam/EPS= Every Pinhole Sucks

#363 JimC

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Posted 05 June 2008 - 06:57 PM

The problem with tortured ply boats, in my opinion, is that there is an inherent conflict between the thickness of ply you can distort into shape and the thickness of skin you want for panel stiffness.

That's something we struggled with in Cherubs for many years. 4mm ply just didn't hack it between daggerboard and bow. Solutions varied from laminating up extra ply in cold-moulded type strips under the bow to just layers of glass or something. I think IIRC AndyP gave up the idea and cold-moulded his boats under the chines, then went to ply sandwich with glass each side of the ply. Vac bagging foam wasn't an option with the tech we had available to us in the 70s and 80s. Its many years since a ply Cherub's been built in the UK though: they're all foam core.

#364 c maas

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Posted 05 June 2008 - 09:00 PM

The problem with tortured ply boats, in my opinion, is that there is an inherent conflict between the thickness of ply you can distort into shape and the thickness of skin you want for panel stiffness.


That looks really good Steve.
I wonder if the best way to get panel stiffness is to glue in one or two longitudinal timber stringers, say 25mm high by 4mm wide. The mast bulkhead could hold them in place.
I know you've done that before.

I'm just now putting the primer on my new boat and seat.
FWIW I have always been unimpressed with kevlar. I've found that s-glass is more effective for dent and puncture resistance, it's better in compression, cheaper and way easier to work with. I do have a roll of very light kevlar cloth that does seem well suited as a peel ply though...

#365 Steve Clark

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Posted 05 June 2008 - 10:36 PM

I'm just now putting the primer on my new boat and seat.

Pictures Chris!
I've shown you mine.
Your turn!
SHC

#366 gui

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Posted 05 June 2008 - 11:05 PM

That looks really good Steve.
I wonder if the best way to get panel stiffness is to glue in one or two longitudinal timber stringers, say 25mm high by 4mm wide. The mast bulkhead could hold them in place.
I know you've done that before.

I'm just now putting the primer on my new boat and seat.
FWIW I have always been unimpressed with kevlar. I've found that s-glass is more effective for dent and puncture resistance, it's better in compression, cheaper and way easier to work with. I do have a roll of very light kevlar cloth that does seem well suited as a peel ply though...


I was going to say that you old farts are full of sh!t, but apparently not:
http://www.azom.com/...p?ArticleID=769
Now I wonder why I bother using kevlar. I like the color ... I guess.

My birthday's coming up soon Chris, and since you won't be needing 2 boats ...

#367 John K

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Posted 06 June 2008 - 12:49 AM

Steve,

That is VERY COOL! So farr you are making it look easier than building a plug. I cant wait to see the finished product. It will be quite impressive if you can hit the minimum weight with a ply seat & hull.

Mayhem is packed & ready for the OSGP, I'll see you Saturday

Best

JK
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#368 Phil S

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Posted 06 June 2008 - 07:52 AM

Steve,
This looks a lot more like what I would have preferred to see. Much more rounded than the first batch of photos. Front is a lot like the LOG. The darts at the base of the stem are a common consequence of the process. Alleviated a little by a larger radius forefoot.

Good debate about interior structure. Important but subject to taste, experience and equipment. Only comment about vacuuming in foam is that this would put the design and its construction out beyond most home builders.

WRT styrofoam, a coat of resin seems to help with water absorption rate, a well as building a boat which does not leak. But then some of us go sailing with the bung out!!

John, I am considering my next moth build and it looks like being a carbon nomex shell molded onto an empty ply shell plug not unlike the structure which Steve has now.

#369 Steve Clark

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Posted 16 June 2008 - 01:54 PM

When last we left our heroes. Steve had declared his intent to vacuum bag Kevlar and foam into the interior of GER 78.
He was envisioning something like this:
Attached File  core__kevlar.JPG   120.91K   76 downloads
He confirmed the hull was straight and met measurement and built a set of cradles ho hold it in shape.
He then bagged in the foam and Kevlar by putting the entire hull in a vacuum bag.
That way he didn't need to worry about the vacuum integrity of the plywood skin.Attached File  bagged_quarter.JPG   145.6K   68 downloads
The boat was then placed back in the cradled to make sure that it stayed the right shape.
Funny thing though, for reasons best known to experts and 29er sailors, the bagging process, which should have been force neutral on the hull skin caused it to roll up more.
Attached File  Bagged_Bow.JPG   125.63K   66 downloads
Not that was a big concern, because I have been trying to get the hull round all along, so a bit more should be cool.
The interior looks very nice, Kind of like I pictured it and the bottom is stiff enough to seriously hurt waves.
Attached File  Core_and_Kevlar.JPG   126.24K   88 downloads
BUT (and there always is a but) that nifty bit of extra roll up means that the boat is just a bit too narrow at the measurement point.
Attached File  Gap.JPG   97.78K   57 downloads
This required a Father's Day full of head scratching, and I think I have solved the problem by making another long saw cut from the dagger board trunk almost to the stern and pushing the boat apart about 2mm. This relieved things just enough.
Photos are a bit odd, looks like it was snowing in the shop.
SHC

#370 Matt D

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Posted 16 June 2008 - 02:43 PM

How about bumps to measure like the B5s used to do?

#371 RogerIC

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Posted 16 June 2008 - 03:18 PM

I think I have solved the problem by making another long saw cut from the dagger board trunk almost to the stern and pushing the boat apart about 2mm. This relieved things just enough.


its good that you can do some plastic surgery before the birth of this baby to ensure its immculate beauty when becoming an IC

#372 Steve Clark

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Posted 16 June 2008 - 04:36 PM

IC rules have aggressive anti bumping rules. Specifically intended to avoid B5 and such like perversions of the measurement rule. There are no short cuts or rule dodges other than making the hull form actually conform to the measurement points.
Fortunately being a designer builder allows me to make subtle changes to the design when new information presents itself...
As discussed earlier, it is pretty impressive how little things have to be changed to make a big difference, I made the cut with one of those Japanese pull saws, so the kerf was a bit less than 1mm wide. The boat naturally sprung open another 1.5-2mm and the chines were wide enough. So screwwed on some bolocks to keep the pieces aligned vertically and pumped the crack full of Gougeon Green slime.
The inside is relieved for the backbone, so there was no consequences there, the outside will get a narrow pass of +/- 45 carbon to make sure nothing untoward happens in the future.

#373 JimC

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Posted 16 June 2008 - 06:15 PM

How about bumps to measure like the B5s used to do?

Bumps on the IC have an effective minimum size of approx 2m by 1m... This is limiting!

Steve, would you have been able to push the topsides out with the deck to make the beam, or would that have compromised other aspects of the shape? Its interesting that you're hitting the minimum hard - one of the things that has caused me some thought is that I understand that the Nethercott wasn't minimum waterline beam under the rule it was designed to. I wonder if it is possible to have a Canoe that is too thin - at least for those of us at the higher end of the total displacement/hull weight ratio...

#374 Steve Clark

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Posted 16 June 2008 - 07:12 PM

Steve, would you have been able to push the topsides out with the deck to make the beam, or would that have compromised other aspects of the shape? Its interesting that you're hitting the minimum hard - one of the things that has caused me some thought is that I understand that the Nethercott wasn't minimum waterline beam under the rule it was designed to. I wonder if it is possible to have a Canoe that is too thin - at least for those of us at the higher end of the total displacement/hull weight ratio...

The cored bottom is stiff enough that pushing the topsides around has almost no effect.
Minimum beam at the waterline seems like a good idea. The Nethercotts were designed when hiking out on a 14 was regarded as very athletic. The FD and 505 were regarded as boats for gymnasts only and aluminum rigs weighed 11 kg. Moths less tan a meter wide were considered too hard to sail. So we sail a bit better than our parents did and with advances in materials ( carbon masts and Mylar sailcloth) boats that were untenably tippy aren't so bad.
A bit more beam at deck level seems like a good idea even though it has no benefit with regard to sail carrying power. Giving the helm some room to move about should make tacking and gybing more like a Nethercott than a Hollow Log or Tin Tear Drop Mk1.
Time will tell how it all turns out.
SHC

#375 Phil S

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Posted 17 June 2008 - 10:10 AM

Steve, I had the same problem with the Hollow Log, at first it was 3mm too narrow. But I was able to split the chines for 200mm and push out the topsides before adding the internal carbon and bulkheads.

Jim, you must appreciate that on Steve's boat the chines are much more parrallel near the measurement station,so pushing out the chine would have created an illegal bump. And the foam and kevlar would have made it impossible to move anyway.

It sure looks like being a stiff boat. And there will far fewer bulkheads to fit to that lovely shape.

Steve, are you happy with the weight so far?

#376 JimC

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Posted 17 June 2008 - 11:11 AM

so pushing out the chine would have created an illegal bump. And the foam and kevlar would have made it impossible to move anyway.

Bearing in mind that the boat measured before Steve put the foam and fibre on the inside, and that he stated that the shell had got a bit more curvy I figured that the laminate must have shrunk slightly on curing, and that was what brought the chines in. But yes, thinking about it you're right it won't move. When I had my Nethercott down to a bare shell plus inner gunwhales I considered doing some serious bending to slim down the bow and give her a finer entry, but when I applied some force it became quite clear that significant variations in the shape of that shell of rather generous layup were only going to be made by chopping out large areas with an angle grinder and building in new structure. So it didn't happen!

#377 Steve Clark

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Posted 17 June 2008 - 01:12 PM

What is odd is that the vacuum bag did the shape change, not the shrinking of the epoxy on the inside.
I could see the difference when the bag went down. Long before the resin cured and shrank.
What has me puzzled is that as I understand the Planet Rules there should have been no net force applied to the structure. As the whole thing was in a bag.
But there must have been some difference in barometric pressure between the inside and the outside that was enough to cause the skin to roll up.
What amazes me is that I have never seen this in other places. I have seen the differential shrink bit, but not this one.
It may be a useful way to push more curvature into simple plywood shapes, but it is a pain in the ass right now.
SHC

#378 Amati

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Posted 17 June 2008 - 03:39 PM

Steve, once, many posts ago, you observed that what works in Australia doesn't seem to work anywhere else. It may be true for the Eastern Seaboard too.

Name the boat Heisenberg's Uncertainty. It's the Principled thing to do.

Seriously though, did the foam squish under vacuum? I used to get that (some deformation) on some wood/foam windsurfer hulls I did. I think it was because of voids between the bottom of the foam (or in the foam) and the hull.

Paul :lol:

#379 Lost in Translation

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Posted 17 June 2008 - 06:36 PM

Steve, I'd imagine what happened is that the same amount of pressure on both sides had more of an effect on one side rather than the other. Could one of the skins been slightly more flexible than the other? Or, as Paul notes, is this a factor of the core?

#380 TeamFugu

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Posted 17 June 2008 - 07:33 PM

My guess is that there is something about one side having less surface area than the other. I've never seen a vacume bag deflated that vacumed out flat. Even putting a vacume on the odd air matress so I can get it into a smaller space left me with a crinkeld mess. The bottom side would stay flattened out while the top would have folds and creases that would cause the whole to curl.

One way to maybe control this more would be to add a rail to the form and clamp the rail of the boat to it. You shouldn't require a lot of pressure from the clam. Just something to hold it stable. Most applications for a bag are where you have a mold on one side and you vacume the other forcing everything into the mold. The molds is usually very sturdy so it does not flex durring the process.

Just a thought.

#381 atypicalguy

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Posted 18 June 2008 - 02:30 AM

What is odd is that the vacuum bag did the shape change, not the shrinking of the epoxy on the inside.
I could see the difference when the bag went down. Long before the resin cured and shrank.
What has me puzzled is that as I understand the Planet Rules there should have been no net force applied to the structure. As the whole thing was in a bag.
But there must have been some difference in barometric pressure between the inside and the outside that was enough to cause the skin to roll up.
What amazes me is that I have never seen this in other places. I have seen the differential shrink bit, but not this one.
It may be a useful way to push more curvature into simple plywood shapes, but it is a pain in the ass right now.
SHC

Seems like smashing curve into the foam is going to change the shape of the skin before it kicks, as the skin is doing its flexible best to set the shape for the foam in the early stages, and the foam is resisting the skin's efforts, with all the vacuum canceling itself out. So they meet in the middle somewhere - between what the foam wants to do and what the skin wants to do.

#382 Amati

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Posted 18 June 2008 - 03:32 PM

Steve, if you could control the movement of the foam during initial vacuum, like corner/edge/tab glueing it in place (?), and maybe put some cuts into the foam, to control how the foam breaks down under pressure, as you began to infer above, you might really be on to something, as far as developing shape into the hull; foam acting as a dynamic, morphing male mold under pressure- semi destructive moulding.

But you're probably already out in the shed experimenting with this, no?

Paul ;)

#383 Steve Clark

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Posted 18 June 2008 - 05:43 PM

Well I don't really think the foam in breaking down or collapsing given that the compression strength of the foam is 116 psi or a bit more than 10 times the 14psi of one full atmosphere.
The foam is of the contour or scrimmed variety, so the individual pieces are about 1" square, so I don't see them being significant distorter of 3mm plywood either.
What I figure it has to be is that because the volume of low pressure is bigger on the interior ( core and Kevlar side) than on the outside of the hull, there must have been a net some imbalance in the forces acting on the skin such that it moved toward the cored side. But it is hard for me to believe that the differential in pressures was that significant. Maybe I assumed the plywood acts as a better bleeder than it does.
I have done things "about like this" for many years without having this happen. Maybe I have just been lucky, or some other factor, like the fact that the panels are usually flat instead of compounded, has had an effect. It is interesting (and yes) does offer something of an opportunity in the land of compounding plywood shapes. I'm not exactly sure what to do about it though.

#384 c maas

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Posted 18 June 2008 - 06:43 PM

Maybe the distortion is caused by each winkle in the bag pulling itself together as the vacuum sucks them down to the surface. So the vacuum bag becomes a bit smaller and would be more effective at pulling curl into the inside radius that is the hull. Picture a vacuum bag bridging a corner (as I often have the chance to do), it wants to pull the two sides closer together. This is happened to your hull on a bigger but more subtle scale.

Re-reading this theory makes it sound pretty unlikely. I'll submit it anyway.

It seems lthat if anything the closed cells in the foam would expand under vacuum causing the foam to get bigger and you would see just the opposite result - the panel would flatten. In fact I'm now conviced that what you experienced can't have happened. Problem solved.

#385 MT Sailor

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Posted 18 June 2008 - 07:57 PM

Ok - How about this....

As the bag collapses under vaccum pressure, it pinches in on the edges before it comes tight against the inside of the hull. It can slide around the edges to some extent, but as it is pulled into the center of the curve the pinching against the edges causes it to pull with a small force towards the center of the hull, thus increasing the round. So everyone is right that the net atmospheric force once the vaccum is established is zero, but there are forces at work as the air is being removed, creating uneven tension in the bag that remains as long as the vaccum remains.

#386 Steve Clark

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Posted 18 June 2008 - 10:52 PM

A picture, so it must have happened.
Attached File  Bagged_stern.JPG   142.47K   66 downloads
Notice that the bag film is nice and lose with no bridges inside the hull.
Bag film is also much stretchier than 3mm plywood.
Perhaps it is the work of a small troll or daemon.....
SHC

#387 TeamFugu

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Posted 19 June 2008 - 12:04 AM

A picture, so it must have happened.
Attached File  Bagged_stern.JPG   142.47K   66 downloads
Notice that the bag film is nice and lose with no bridges inside the hull.
Bag film is also much stretchier than 3mm plywood.
Perhaps it is the work of a small troll or daemon.....
SHC

Or it did it just to piss you off. Kind of like the frustration detector they put in copy machines where their ability to perform the assigned task is inversly proportional to your need.

#388 MT14er

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Posted 19 June 2008 - 02:18 AM

Actually I have an idea of why this may have happened. So when you vacuum bag a convex surface the bag pulls (is pushed actually) onto the curved surface. Once the film comes into contact with the surface and begins to apply some pressure the composite material is compressed slightly. On a convex surface this results in slightly smaller total surface area so there is no tension on the bag. But when you compress the concave surface the surface area of the composite needs to increases slightly as it is pushed down (not much, but a bit). With the bag firmly pressed against the hull at this point, the bag needs to stretch slightly all over the surface to accommodate the extra area created at the moment of compression, which would produce a slight bending force. Possibly.

#389 atypicalguy

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Posted 19 June 2008 - 05:24 AM

Actually I have an idea of why this may have happened. So when you vacuum bag a convex surface the bag pulls (is pushed actually) onto the curved surface. Once the film comes into contact with the surface and begins to apply some pressure the composite material is compressed slightly. On a convex surface this results in slightly smaller total surface area so there is no tension on the bag. But when you compress the concave surface the surface area of the composite needs to increases slightly as it is pushed down (not much, but a bit). With the bag firmly pressed against the hull at this point, the bag needs to stretch slightly all over the surface to accommodate the extra area created at the moment of compression, which would produce a slight bending force. Possibly.


Yes if the foam is stress relieved with cuts into blocks then resistance to bending seems unlikely, and as a backup I'd go with the differential bag tension theory. Or Chris' idea that it was all just a bad dream, complete with photo ops. Sort of reminds me of the dream I had one time that I was awake and floating around the room, looking at myself sleeping, in real time. When I woke up, everything in the room was exactly how I had dreamed it - except the dresser had a bit more curve in the top...

#390 Phil S

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Posted 19 June 2008 - 08:19 AM

I have another theory which has nothing to do with the vacuum or the foam.

The stressed ply shell will get wider and flatter in the middle if supported at either end, and conversley the middle will get more rounded and narrower if the ends are lowered relative to the middle. Even ever so slightly.
Steve said he made the cradle between checking the dimensions and vacuuming in the foam.
Would it be possible that the hull when resting in the cradle was well supported in the middle and the ends slightly dropped, narrowing the beam midships and rounding the bottom slightly.

An alternative is that the vacuum bag with maybe a few folds between the cradle and the hull was sufficient to narrow the hull enough to fail measurement?

#391 bistros

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Posted 19 June 2008 - 10:46 AM

I have another theory which has nothing to do with the vacuum or the foam.


Maybe he didn't use the same ruler on one set of the measurements. Perhaps the cradle changed. Environmental conditions and humidity may have changed. This is wood we are talking about. This thread has been looking only at one possible result: the IC changed - perhaps the deviation was elsewhere.

Perhaps the result is a combination of minor change to the IC and minor changes to to measurement and environment.

I am not doubting Steve Clarke, but when hunting for causes of unexpected results, it pays to consider things from many possible perspectives. Everyone is concentrating their focus on the materials & vacuum bagging process.

Forensic engineering is one situation where Occam's Razor(1) is best ignored. Trying to find a simple solution to a complex issue doesn't always work. Calibration and verification of measuring systems is the first place to start.

1 - "All other things being equal, the simplest solution is the best."

#392 TeamFugu

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Posted 19 June 2008 - 01:03 PM

OK how about some real R&D testing. Make several similar boats and try out a few of the discussed ideas. Find out what is really happening and let everyone know. Then the resulting hulls could be sold to people who want in on the DC life and you pay for your R&D as well as grow the class.

Once you have it all sorted out, sell kits.

#393 Steve Clark

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Posted 19 June 2008 - 02:47 PM

Measurement process is consistent. In other jobs I have measured literally hundreds of boats, so the tapes and jigs were all OK and their calibration was confirmed when odd numbers started showing up.
Jig was molded off of hull when it was braced in the correct dimensions. It curled away from the fixture as the vacuum came on.
I guess it's possible that the Kevlar was tight and that was the culprit, but it was sliced down the middle. Just never seen it do that before.
Oh well, solution is well in hand and we have had a wonderful time talking about it.
Our relationship has remained fresh and vital as a result.
SHC

#394 JimC

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Posted 19 June 2008 - 03:06 PM

Jig was molded off of hull when it was braced in the correct dimensions. It curled away from the fixture as the vacuum came on.

Supposing you hot wired a piece of styrofoam into a hull cross section and put a vacuum on it and looked to see if it changes shape. That might test out some of the theories about shape without too much time and trouble. Are any of the models for the tortured boas deck less? Could you put a dry vac down on one of them and see if something happens?

#395 bistros

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Posted 19 June 2008 - 03:15 PM

Measurement process is consistent. In other jobs I have measured literally hundreds of boats, so the tapes and jigs were all OK and their calibration was confirmed when odd numbers started showing up.
Jig was molded off of hull when it was braced in the correct dimensions. It curled away from the fixture as the vacuum came on.
I guess it's possible that the Kevlar was tight and that was the culprit, but it was sliced down the middle. Just never seen it do that before.
Oh well, solution is well in hand and we have had a wonderful time talking about it.
Our relationship has remained fresh and vital as a result.
SHC



Steve - I wasn't intending to doubt you, I was just trying to get people to think outside the most obvious box. I've been on product development process bug/witch hunts many times and it is surprising how many incident causes are the result of unpredicted combinations of circumstances and timing. With a production process sample of one, you really do not have enough data to figure out the cause.

#396 Amati

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Posted 19 June 2008 - 03:57 PM

I still like my quantum theory explanation. Granted it's a lot of jumps at the same time, but as Bizzarro World Statistical Analysis Theory would agree, Steve's built a Lot of boats. Maybe things jumped to Phil's shop. Phil, have you looked? They might still be there.

:lol:

Although there is the 'what was playing on the shop boombox explanation'. If you went from the Dead Kennedys (say 'Trust Your Mechanic' off of 'Plastic Surgery Disasters') to Kenny G (any Kenny G) at the proper moment, it might relax wood and foam enough that the vacuum, supports and gravity would have their way with shape. If not your mind. Perhaps you would not be able to account for a few minutes of your own existence, which might explain mistakes.

Not to say this is what happened. But I didn't want all those corporate leadership classes my wife has had to suffer through go to waste.

:ph34r:

Paul

#397 Phil S

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Posted 20 June 2008 - 07:56 AM

I still like my quantum theory explanation. Granted it's a lot of jumps at the same time, but as Bizzarro World Statistical Analysis Theory would agree, Steve's built a Lot of boats. Maybe things jumped to Phil's shop. Phil, have you looked? They might still be there.


I looked in the shed and the canoe is there but only 1/4 the size, seems to measure in though:
Attached File  canoe_mod.jpg   83.81K   35 downloads

#398 John K

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Posted 20 June 2008 - 11:54 AM

I looked in the shed and the canoe is there but only 1/4 the size, seems to measure in though:
Attached File  canoe_mod.jpg   83.81K   35 downloads



Phil,

Your photo is just a tease.
These plywood stich & Glue boats are generating some pleaseing shapes. Please post more photos.

Chris, I am looking forward to seeing what have you created in the PNW?

John
USA-244 "Mayhem"

#399 Phil S

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Posted 20 June 2008 - 12:31 PM

Like this John,
Attached File  08__007.jpg   109.4K   53 downloads
Posted previously.

#400 Amati

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Posted 20 June 2008 - 03:18 PM

I looked in the shed and the canoe is there but only 1/4 the size, seems to measure in though:
Attached File  canoe_mod.jpg   83.81K   35 downloads


Now THAT'S what I'm talkin' about!! How long before it takes the obligatory jump back to Steve's place?
(I'd suggest tying it down, but String Theory has been superceeded, no?)

ok, I'll stop now. :P

Paul




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