DC Designs

TimClark

Super Anarchist
1,441
0
NYC
Started my DC build - just jig at the mo. but taking shape! Based very loosely (down to min beam) on Lust Puppet offsets provided by Steve; Cheers by the way! Took a bit of rocker out Aiming to stitch/glue/carbon 3mm gaboon ply reminisant of Phils holllow log. Hopefully keep it down to weight

As it is my first build I'm trying to keep it simple - nice hard chines should keep her pretty stable.

View attachment 60403

Any advice much appreciated.

AP
It'll be fun to see how it turns out. I was thinking about doing a similar project next year for my senior experience project but there are so many routes to go. What are you planning on doing with the exterior of the hull(carbon or glass?)

TC

 

gui

Anarchist
Started my DC build - just jig at the mo. but taking shape! Based very loosely (down to min beam) on Lust Puppet offsets provided by Steve; Cheers by the way! Took a bit of rocker out Aiming to stitch/glue/carbon 3mm gaboon ply reminisant of Phils holllow log. Hopefully keep it down to weight

As it is my first build I'm trying to keep it simple - nice hard chines should keep her pretty stable.

View attachment 60403

Any advice much appreciated.

AP
You should pm atypicalguy ... He is the current owner of LP. Better yet, drop a mail to Mr Beaver. I bet they have some idea on how to improve LP.

Good luck with the project.

 

Phil S

Super Anarchist
2,595
224
Sydney
At McCrae Lust Puppet looked wide, blunt and heavy compared to the new DCs. Jon sailed well often enough to show it was not really up to pace with 2007.

The shadows set up in the photo look like your boat is too blunt, maybe too wide and in my pinion too Veed, by today's standards. I like rounded sections below the chine to minimise wetted surface although Allister's boat proved a V bow is fast enough.

To build a stressed ply boat like the Log does not require any jig at all. At least some of the intrinsic strength comes form stressing the panels into curved sections. If you lay plyt sheets over that jig the flat panels will require additional support inside, so it might not be as easy to get down to weight.

FWIW

Phil S

 
At McCrae Lust Puppet looked wide, blunt and heavy compared to the new DCs. Jon sailed well often enough to show it was not really up to pace with 2007.
The shadows set up in the photo look like your boat is too blunt, maybe too wide and in my pinion too Veed, by today's standards. I like rounded sections below the chine to minimise wetted surface although Allister's boat proved a V bow is fast enough.

To build a stressed ply boat like the Log does not require any jig at all. At least some of the intrinsic strength comes form stressing the panels into curved sections. If you lay plyt sheets over that jig the flat panels will require additional support inside, so it might not be as easy to get down to weight.

FWIW

Phil S
Of course LP is wider and heavier than DCs. She was built to an entirely different rule when the minimum weight was much higher. She is class legal at IC regattas in the US under the old National Canoe rule, which the DC rule was largely cribbed from. But she was never legal in international IC competition because she was built in 1985 or so by Bill Beaver, and the only National Canoes grandfathered into the IC rule were built before 1960 or something.

If you were in turn to compare a Nethercott to Lust Puppet, the Nethercott would look wide and blunt. DCs should be viewed as another iteration down the same path as Lust Puppet took - long before it was fashionable or there was any talk of making it class legal BTW.

In terms of competitiveness, I really do not think it fair to either Jon or the boat to say that he sailed her to her or his potential, as he had never laid eyes on her prior to the event, and she had some structural issues during the event. I sailed and improved her for three or four years and actually only toward the end of that time felt I was sailing her to her potential - occasionally taking some races off people like John Kells and Bill and at least mixing it up with the front of the IC fleet when I sailed well. This is doing pretty well considering their boats were/are carbon/nomex and I was sailing twenty year old plywood with a seat that sticks to the water like white on rice when it hits, and a plywood shark fin rudder from the same era. Jon may be a much better sailor than I am, but that boat takes some getting used to.

So to say she is not up to pace with 2007 depends upon what boat you are comparing her to. She sailed as a DC at Worlds because the US fleet wanted to put the class on a firm footing numbers-wise, and she clearly does not meet international IC rules. But her performance should really be evaluated vis-a-vis the the Nethercott if Apples are to be compared with Apples. I would say that with a better seat and carriage, a modern more balanced rudder, and some lowers, she would be fully competitive with any Nethercott across a range of conditions, and superior in the light. Full carbon boats are lighter in the ends but LP cuts through chop better and cuts down on wetted surface enough offwind in the light to compensate. She is markedly more tender than most Nethercotts however and this sometimes spells disaster in the tacks. The V-bottom raises the chines high enough that they do not do much for stability, because by the time they hit the water the rig has enough roll momentum to just carry on in whatever direction it happens to be rolling. She probably has too much rocker though this can be fun in the breeze on reaches and upwind when the whole front of the boat is up in the air. The only reason people are still talking about that boat is because she showed that moving away from the Nethercott hull shape could create real performance improvements, and could be easier to build at the same time, from basic plywood. This is the lesson to be learned from the boat in my view. Now of course we have a whole gaggle of DCs demonstrating the potential of alternative hull shapes, but they are much lighter of course, and many are carbon/foam.

Bill iterated on LP and Sock Puppet (now Gui's boat) was the result. In terms of hull performance she met most of Bill's goals which if I recall correctly included better performance to windward in chop and more initial stability (from an arc bottom and two chines per side rather than one). She was built by John Williamson with an aluminum carriage and Bill has told me more than once that he felt he was never able to sail her to her potential because she was not set up to his liking in terms of DB position, rig, seat/carriage, etc. He fixed some of these things over time but never really got the boat set up to his liking.

Bill has said on the Canoe list that he feels he could make a minimum-weight chined Sock Puppet-like DC from plywood reinforced strategically with composites. I think it was 2mm sides/bottom and 3mm deck. The goal here is to provide people with the interest and motivation an easy way to put a hull together at minimum weight and cost. The thought would be to have these panels CNC'd by a wood shop like Chesapeake Light Craft and then use stitch-and-glue methodology to form the hull without a jig, or just print the patterns and cut by hand. How such a boat would perform against the current crop of DCs is anyone's guess, but that's what the rule is all about, right? Build your idea and see how it shakes out on the course.

I did take SP's lines and remove some beam, then converted the bottom to two flat panels creating a shallow V bottom and hopefully more stability. I have unfolded these panels in a CAD program and can send the file to whomever wants it, provided Bill is OK with that (he is still in NZ I think). Bill said he liked the look of the result but I'm sure he would blast out another iteration in Maxsurf or whatever he uses at work before building anything. IIRC I am at min beam at the bottom of the box and wider at the top for shroud base width. I need to double check the height at the beam measurement station, but I think it makes the 275mm rule (though I can't find the change to 275 from 300 in the draft rule Phil). No fancy deck wedges at the shroud plates or anything. This boat is essentially Sock Puppet, but skinnier and with even less flare forward. It would be possible to make the boat skinnier yet and talking to a few people who were at Worlds this would certainly be tempting, though it might not be necessary given Phil Robinson's example.

Were I building I would have panels laser or waterjet cut from carbon/foam stock or plywood and tack them together somehow. I was not at Worlds but 21 Log Jump seems all the rage and I have to say Phil's torturing ply method seems to offer many of the same advantages in building a totally different shape that requires less reinforcement than a flat paneled boat would require. His method may be the best marriage of home buildability, low cost, and rounded hull shape.

On aesthetic grounds I am wedded to the notion of form following function, though I am a bit of a traditionalist. I do not particularly like the look of String Theory as a canoe, for instance, though the craftsmanship is jaw-dropping, and she is clearly fast. So in all my spare time, I would like to build something a bit more conventional in appearance and see where it stacks up against the Log Theories and Scarlet Mascaras of the future.

 
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Steve Clark

Super Anarchist
Phil, the correct response to the first new IC to be started in Kiwi in more than 10 years is "THAT'S GREAT!"

AP, glad to see you make a start. I think 50 kg Lust Puppets will be good boats.

You should consider letting some stringers or battens into the mold to keep the ply straight. Takes a bit of care at this stage, but saves time down the road.

Both the Lust Puppets built in the US were built over bulkheads that stayed in the boats.

SHC

 

gui

Anarchist
I'm not convinced by the flat bow design, SP slams a lot uphill in a shop and doesn't feel fast at all. Maybe due to bad sailing or lack of rm (I'm 145lbs), dunno. However, in flat water, it's quite the weapon.

Karl was always quick with LP, so a skinny/lighter version should be a pretty good boat.

 

Phil S

Super Anarchist
2,595
224
Sydney
Yes Steve, any new canoe is good news.

But since AP mentions my boat in his post I figured I should help him create a boat from this century not last century.

Even though Karl and Gui have good comments on the Puppets, I think all of us who sailed at McCrae appreciate that the performance of the best new boats especially String Theory have significantly raised the bar.

I also do not see any point building a boat the hard way when the Hollow Log way is so much easier, lighter and quicker still using the same materials. And he has not yet started cuting those materials.

AP , why not build one of each?

 
Yes Steve, any new canoe is good news.But since AP mentions my boat in his post I figured I should help him create a boat from this century not last century.

Even though Karl and Gui have good comments on the Puppets, I think all of us who sailed at McCrae appreciate that the performance of the best new boats especially String Theory have significantly raised the bar.

I also do not see any point building a boat the hard way when the Hollow Log way is so much easier, lighter and quicker still using the same materials. And he has not yet started cuting those materials.

AP , why not build one of each?
Stitch and glue is a very easy construction technique also, and really not so different from what Phil is describing, though his system has fewer seams and nice, rounded profiles which are attractive, strong, and ultimately should make a lighter boat. But AP you are off down the garden path so to speak, so kudos for that. Building something is far more important than building any specific design or method.

As for LP-like shapes and their potential, I guess we will have to wait until a good sailor builds one as a DC and sorts it out fully, and then see how it goes.

KW

 

gui

Anarchist
Yes Steve, any new canoe is good news.But since AP mentions my boat in his post I figured I should help him create a boat from this century not last century.

Even though Karl and Gui have good comments on the Puppets, I think all of us who sailed at McCrae appreciate that the performance of the best new boats especially String Theory have significantly raised the bar.

I also do not see any point building a boat the hard way when the Hollow Log way is so much easier, lighter and quicker still using the same materials. And he has not yet started cuting those materials.

AP , why not build one of each?
Well, you're probably right. If I were to build a canoe, it would be based on Chris's boat/yours. I was impressed by what I saw in Ram Island, Chris would usually screw up his starts (noze dive or similar screwy stuff), but still catch up the front guys by the middle of the first beat.

I think the old farts (;p) complained about it not looking like a canoe ... But a bit of mind stiring is always good.

G.

 

Chris Maas

Member
395
10
Well, you're probably right. If I were to build a canoe, it would be based on Chris's boat/yours. I was impressed by what I saw in Ram Island, Chris would usually screw up his starts (noze dive or similar screwy stuff), but still catch up the front guys by the middle of the first beat. I think the old farts (;p) complained about it not looking like a canoe ... But a bit of mind stiring is always good.

G.
The features that make String Theory un-traditional in a 1970's sense are relatively superficial. It would be easy to get an adequate shroud base without the winglets, the foredeck could (should?) be convex and the stern could be pintailed more. My next design is heading in that direction. Not for reasons of tradition but because I think it will be faster.

And thanks for bringing up my less than stellar performance at Ram Island! ;)

 

nzintcanoe

Member
58
0
Yes Steve, any new canoe is good news.But since AP mentions my boat in his post I figured I should help him create a boat from this century not last century.

Even though Karl and Gui have good comments on the Puppets, I think all of us who sailed at McCrae appreciate that the performance of the best new boats especially String Theory have significantly raised the bar.

I also do not see any point building a boat the hard way when the Hollow Log way is so much easier, lighter and quicker still using the same materials. And he has not yet started cuting those materials.

AP , why not build one of each?
Based loosely on LP. The offsets were a starting point from which I've made a few changes.

I had been thinking about rig a bit when deciding on hull type and the limits of my building skills. One thing to keep it simple was to put a stayed rig on so needed some beam. It is quite close to the min at 760mm. I did flatten the chines out and take quite a bit of rocker out and am quite happy with how the shape looks at the mo. Before I start cutting I may take out some volume out of the bow.

The master plan is to start building boats "build them and they will come" the best method may be getting the 'logs' going; time and interest will tell.

Yes I'll need a bit more structure inside but I don't think it will be too heavy with the sheer height at the stern kept to a minimum and toying with the idea of foam panels inside.

Cheers

AP

 

Phil S

Super Anarchist
2,595
224
Sydney
AP

Make sure you are working to the latest vesrion of the Development Rule. There were a few refinements made late last year and the latest version on which the IC association will vote shortly is on the IC Forum: http://www.intcanoe.org/forum2/viewtopic.php?t=687

There are some small changes from the old version on the IC web site. eg Freeboard was reduced to fit the Nethercotts in and some clarifications about allowable plan form curves.

Have fun building and sailing the canoe. These new light boats are great value in terms of speed and satisfaction for the dollar.

Phil S

 
So can someone tell me why Phil Robin had all those DNCs on his scorecard? Looked like a structural issue from the scores but didn't want to presume.
No structrals, he had just general stuff like a broken forestay.... Typical bad luck regatta, but the boat itself appeared strong and was very quick in the last heat of the Worlds

 
Phil had standard new boat teething issues. Lashings chaffing through and the like, the kind of stuff you expect when the boats only had a couple of hours on the water. Definitely had speed though..

 

TeamFugu

Super Anarchist
5,049
19
SLC, UT
FWIW there are a couple advantages to using foam for the bulkheads. The first is that they are easier to shape than using wood. And another that many don't think about is that if you hit something close to a bulkhead, the bulkhead will give a bit where wood will most likely cause the skin to shear at the joint between the bulkhead and the hull. Sure it is not good to hit things but having your 3mm ply tear is more of a deal breaker than a little dent and some crazing.

 

Willy Clark

Member
187
63
Boston, MA
Its about time I did this, So here is what I think:

The Worlds in itself was a blast and kudos to Christian for putting on a great regata. McCrae yach club is one of my favorite places on Earth, the competition was good and the RC was one of the best I have ever had.

I think Hayden, Oliver, Phil and Dad have all done a pretty good job of describing the different desighns so I will give a breif synopsis of my thoughts. I will try to focus more on how they feel when sailed and the various difficulty levels rather than the design because that is an area for more qualified people.

I was sailing Kaito, the third Josie ever built and is basically identical to Dad and Olivers boats. The boat was plenty fast and the major reason that I did not do better was lack of time in the boat. The lack of practice on my part made my boat handling and tactics suspect at times and also contributed to breakages which cost me at least two boats. My upwind speed was great. When I turn the boat down and start footing it goes like a bat out of hell. However, I had more trouble than Dad and Oliver in bringing the boat back up and as a result I really couldnt point with anyone. But again I think this my defficienceis as a sailor not as a builder. Down wind I was not fast and neither were Oliver or Dad so that actually might be a design flaw. however none of us have ever been fast downwind anyway so it's hard to say. The first thing I am going to do to this boat is put a gybing dagger board on it or maybe a flapper cuz I felt that made all the difference between Olivers boat and my own. I also would built the boat out of foam not nomex because the nomex does not fit the mold very well but I think is more trouble than it's worth.

My boat is every bit as fast as Dad's but he sailed a better regata and thus beat me...............again.

Oliver in Uncle Walter was quite fast. Like I said the difference I think was the gybing dagger board.

David in Alice, a wider and heavier desighn, was still quite fast, particularly upwind. I recommend that anyone who doubts their ability to sail a new rules boat consider something like alice. She is wider and therefor easier to sail but still perfectly competetive.

The first DC not in the family that I got a ride on was John Kells' "Mayhem." The boat is quiet and smooth and he really moves down reaches. Again the boat is not quite minimum beam so anyone with doubts should consider something like that. I particularly like his bow. When I feel that I deserve a new DC I will probably add rocker forward to make the bow slap less and add beam aft.

The next I sailed was Alastair Warren's "Monkey" which had a very different feel to it. I really did not get the greatest idea of how it or John's actually go because I sailed them before the breeze came up. However Alastair's deffinitely felt much more skiffish to me. In the puffs there were downwind I deffinitely felt the boat rear up on its' stern, pop the bow out, and take off. I have trouble giving an oppinion on Monkey, it is deffinitely fast, but it is so different from most of the others that it is hard to compare. I like the V bow though, i think skipping along the top of waves rather than diving through them has something to be said for it. It was also one of the easier boats to sail.

I was very excited to next jump into Phil Stevenson's "21st Century Hollow Log" primarily because he passed me downwind so many times during the regata. Basically if I did not beat him to every windward mark I would not see him again for the rest of the race. The boat hauls ass downwind. Its quite a funny feeling as you sit there with your feet on the gunnels thinking "well this is quite nice" and then look at you wake and realize how fast you are going. It really motors down reaches and I think Phil held his own upwind though there is definitely room for improvement there. The high free board aft did make it rather like balancing on a log however that is nothing that simple practice can't solve.

Unfortunately I was not able to sail Del Olsen's "Donkey" but it seemed pretty quick. I could beat him upwind but he was quick down wind. That could be due to our weight differential.

Rob Patterson was sailing "Wonk" and having sailed the boat before the worlds I do not think she is as difficult as everyone thinks. The bow will dive and she has a high aft deck which makes her unstable however practice I think is the solution here. Rob was skippering for the very first time and also was very new to canoes which explains his struggles. It also was not the best boat to learn on however the boat is fast and upwind I think the wavepeircer really helps.

Finally there is Chris Maas' "String Theorey." With the exception of "Cogito" this was far and away the coolest boat I have ever sailed. I can't remember the last time I had so much fun in a boat as I had sailing Chris.' The boat cuts right through the water as if it is not there (I joked with Chris that he could have put it on foils and I would not have noticed). It seems like it has the perfect amound of rocker forward and the wider stern gives it stability aft which is particularly nice in capsize recovery. Anyone who is not sold on the DC would be if they took Chris' boat for a sail in any kind of decent breeze. It was the best sail I have had in years and I really did not want to give the boat back.

Unfortunately I was not able to sail Phil Robin's boat. I would have liked to seeing as he was the only one to beat Chris in a race that Chris finished but I suppose I will have to wait for another time.

This is getting long so I will wrap it up with saying that to me the DC is the way of the future. The class is more excited than I can ever remember it being and the future finally looks bright. I came away from that regata feeling more positive than I ever have.

Hope you all share my sentiments

If you want my full worlds/DC reaction check the IC my article in the IC news letter coming soon

Thanks

Willy

 
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John K

Member
First things first. A very big thank you to Christian Knott, Nicole and our host in McCrae. It was a great event!

Next, big congratulations to Hayden & Chris for doing so doing so well. Both showed up with well prepared boats and both sailed very smart races.

The biggest success of the whole week was the enthusiasm by all who attended to adopt the “DC” rule as the new IC. I could not be happier. There was a sense of unity and agreement in the direction of the future within the class that was not evident in Bristol or from what I have heard, Weymouth. I am very much looking forward to once again owning an IC, and letting the whole name “Development Canoe” becoming a happy footnote in the history of the class.

For me, getting to McCrae was a victory in it’s self. Construction started in mid April 2007, and Mayhem USA-244 was finished at the end of October just two days before getting packed into the container. The boat measured in, and made minimum weight. Better yet the boat handled as I had intended. The design criteria that I established for myself was as follows:

• To have the hull wide enough at the chainplates to provide adequate support for the mast.

• Relatively full “U” sections forward to promote early planning on the forward sections.

• Moderate beam in the stern sections to reduce the tendency to push the bow down and to reduce wetted surface area.

• The stem is tall enough to keep the foredeck dry in most conditions.

• A strong chine to shed water starting just forward of the chainplates.

• Moderate rocker (100 mm), with maximum draft located at the daggerboard

• To achieve minimum weight

First impressions are that the boat is fast, and has great potential. Unfortunately, I had my share of new boat issues, and I was late for two starts while making repairs on the beach, and I withdrew from one race after my Vang exploded during a jibe. Upwind, I was able to point high or go low & fast. I was deadly quick on reaches. I had designed the hull with the thought that I wanted to be able to push hard on the reaches & runs without stuffing the bow under. In all of the racing that we had, I only took water over the bow once.

I need to work out how to best rig the lowers on USA-244. Video shown after the racing revealed significant and undesirable side bend. My lowers were on to tight, and as they are connected to the same tackle as the uppers, I was not getting the desired tension on the uppers before maxing out the tension that I could pull on the lowers. Before seeing the video, I thought that the over bend wrinkles that I was seeing were the result of excessive fore & aft bend.

I had a chance to sail some of the other DC’s, and while I liked some of the other designs, I am very happy with how USA-244 turned out, and I would not trade. Of course, I never had a chance to sail String Theory…..

For any one who is interested, the lines & CAD file for laser cut frames for Mayhem are available (just pm me), The hull plug and other tools are available for use as well.

Regards

John

 
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