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#2501 El Crapitano

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Posted 07 August 2012 - 01:43 PM

5 b says the 45 degree lines intersect not more than 25 mm beyond extremities. In the bottom sketch the 25 mm lower line is not at the extremity. The extremity is the aft end of the hull. The rule doesn't say anything about measuring the extremity at the centerline.

Attached File  Extremity.png   80.17K   3 downloads

Another consideration is the allowed rudder breach. The rules state that a single rudder breach is allowed but nowhere are there any restrictions placed on the breach in terms of placement or shape. I looked up the definition of breach and while it includes a hole, it also includes a rift. The crudder breach is a rift. If the hull is per the rules ignoring the rudder breach, it should be compliant after a single rudder breach is considered.

#2502 John K

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Posted 07 August 2012 - 02:00 PM




El Crap,

Now that a have had a chance to see what you are talking about; If the rudder & associated "Fittings / Hardware" are not part of the hull so as to comply with the maximum length, do you comply with rule 5 b that define the shape of the ends of the hull?

From the class rules:



5 b The projection on to a horizontal plane of the line of greatest beam shall be a continuous curve, and at bow and stern shall lie inside lines which are at 45º to the center-line and which pass through the center line not more than 25mm beyond the extremities.



Best

JK




The hull complies with 5 b (5 b is part of the rules section titled Hull). In the transom area nowhere did I alter the the line of greatest beam of the hull from how Chris built it. The breach in the hull that the crudder slides into is not "greatest beam" so the concave and convex requirements are not applicable.

FYI, I did modify the line of greatest beam at the radii where the 45 degree lines from the stern transition forward. The modification was to increase the radii slightly to ensure compliance with the 60mm convex radius rule.


The third coat of primer went on last night. Being a rookie, painting seems to involve more sanding than painting and maybe more sweating too as the boat has been moved from the cool basement into the hot garage. One more sanding session and the topcoat goes on.

Made the tiller extension yesterday, so no more doo dad parts to make, outside of a suitable roof rack setup.


El Crapitano,

The concern that I have with Rule 5b is the last sentence that defines the shape of the ends of the hull. On the attached sketch, the top illustration shows the intent of the rule, and the bottom illustration shows where there may be a problem.

Feel free to give me a call

Best

John


John,

this concerns will also apply to any Chris Maas hull which have the slot for the rudder cassette opened to the end of hull. The only difference to El Craps crudder i see is that Chris rudder cassettes are not extending the hull when they are fixed in the slot. And as far as i know all Chris Maas boats did measure without problems...

Roger


Roger,

The difference between El Crapitano's boat and other boats designed & built by Chris Maas and others with a tilt up rudder is that El Crapitano is defining the cassette as “Rudder Hardware or a Rudder Fitting” that is allowed to extend beyond the hull so that he remains within the hull length limit.

In the case of other boats with the rudder cassette in an open slot at the stern, the rudder cassette is measured as part of the hull, and is within the 5200 mm length limit.

The historically the cassette has been accepted as an extension of the hull. I understand the exclusion that allows rudder fittings and hardware to extend beyond the 5200 mm length limit, but if the cassette is not part of the hull for the purposes of measuring length, it cannot be part of the hull for the purposes of defining the shape of the ends of the boat.

John



#2503 El Crapitano

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Posted 07 August 2012 - 02:27 PM

Roger,

The difference between El Crapitano's boat and other boats designed & built by Chris Maas and others with a tilt up rudder is that El Crapitano is defining the cassette as "Rudder Hardware or a Rudder Fitting" that is allowed to extend beyond the hull so that he remains within the hull length limit.

John



Bingo.

The extended part of the cassette has rudder functions and it is attached to the rudder not the hull. It functions as an endplate and it makes a convenient handle for removing a tight fitting cassette. It's axial length is in line with being a rudder fitting, overhanging the rudder by just enough to provide protection to the trailing edge.

The rudder shaft resides within the the rudder cassette so the cassette performs the mandatory rudder function of holding the rudder shaft to the hull. While the cassette has some hull-like attributes, the hull would function well without the cassette, the rudder would not.

Given that the cassette slides into a breach in the hull, the cassette is not part of the hull.

#2504 RogerIC

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Posted 07 August 2012 - 03:01 PM





El Crap,

Now that a have had a chance to see what you are talking about; If the rudder & associated "Fittings / Hardware" are not part of the hull so as to comply with the maximum length, do you comply with rule 5 b that define the shape of the ends of the hull?

From the class rules:



5 b The projection on to a horizontal plane of the line of greatest beam shall be a continuous curve, and at bow and stern shall lie inside lines which are at 45º to the center-line and which pass through the center line not more than 25mm beyond the extremities.



Best

JK




The hull complies with 5 b (5 b is part of the rules section titled Hull). In the transom area nowhere did I alter the the line of greatest beam of the hull from how Chris built it. The breach in the hull that the crudder slides into is not "greatest beam" so the concave and convex requirements are not applicable.

FYI, I did modify the line of greatest beam at the radii where the 45 degree lines from the stern transition forward. The modification was to increase the radii slightly to ensure compliance with the 60mm convex radius rule.


The third coat of primer went on last night. Being a rookie, painting seems to involve more sanding than painting and maybe more sweating too as the boat has been moved from the cool basement into the hot garage. One more sanding session and the topcoat goes on.

Made the tiller extension yesterday, so no more doo dad parts to make, outside of a suitable roof rack setup.


El Crapitano,

The concern that I have with Rule 5b is the last sentence that defines the shape of the ends of the hull. On the attached sketch, the top illustration shows the intent of the rule, and the bottom illustration shows where there may be a problem.

Feel free to give me a call

Best

John


John,

this concerns will also apply to any Chris Maas hull which have the slot for the rudder cassette opened to the end of hull. The only difference to El Craps crudder i see is that Chris rudder cassettes are not extending the hull when they are fixed in the slot. And as far as i know all Chris Maas boats did measure without problems...

Roger


Roger,

The difference between El Crapitano's boat and other boats designed & built by Chris Maas and others with a tilt up rudder is that El Crapitano is defining the cassette as “Rudder Hardware or a Rudder Fitting” that is allowed to extend beyond the hull so that he remains within the hull length limit.

In the case of other boats with the rudder cassette in an open slot at the stern, the rudder cassette is measured as part of the hull, and is within the 5200 mm length limit.

The historically the cassette has been accepted as an extension of the hull. I understand the exclusion that allows rudder fittings and hardware to extend beyond the 5200 mm length limit, but if the cassette is not part of the hull for the purposes of measuring length, it cannot be part of the hull for the purposes of defining the shape of the ends of the boat.

John


John

i think it doesnt matter how something is called - it only counts what it is. Are the cassettes of the Chris Maas boats part of the hull ? Then the crudder cassette should be part of the hull too. If the Cris Maas hulls (or others build similar) measure without the cassette in place, the cassette could be viewed as a part of the rudder. But that looks like rule cheating for my since the rule was intended for normal transom attached rudders and not cassette holded ones


Roger

#2505 Phil S

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Posted 07 August 2012 - 09:07 PM

It would be easy to argue that the "the rudder" which is exempt from the LOA measurement should be only the part which turns to steer the boat, and hence any part of the rudder assembly which does not turn, should be included in LOA assessment. In other classes any to this exemption only covers fittings for attachment, and in our moth class there are restrictions about any fairing or attemptrs at hull form extension.

#2506 El Crapitano

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Posted 07 August 2012 - 10:45 PM

It would be easy to argue that the "the rudder" which is exempt from the LOA measurement should be only the part which turns to steer the boat, and hence any part of the rudder assembly which does not turn, should be included in LOA assessment.


The rule says that the hull is measured for length unless the rudder, fitting or hardware is wider than 50mm athwartships. Nowhere is the crudder, crassette, fittings and hardware wider than 50mm, not individually and not together.

Before today if you asked someone to hand you their IC rudder, they would hand you the rudder assembly with the cassette and tiller attached.

In other classes any to this exemption only covers fittings for attachment, and in our moth class there are restrictions about any fairing or attemptrs at hull form extension.


The cassette is the fitting for attachment of the crudder.

I read the moth rules but decided that an IC was a better match for me. :D


I am new to IC's and don't know the history like most of you. When I read rule 5, because of the number of words and focus on the 50mm exception, I thought that endplates were technically needed to get the rudder to perform at the highest level. It seemed like the rule was providing a strong hint. One of the IC challenges is that decent resolution pictures of latest generation, stationary ICs are rare on the web and pix of IC's on land showing rudders and daggerboards are virtually non-existent.

I learned a lesson as a freshman in college about sticking up for what you see. My first exam was in an engineering design class. One of the questions was to fill in a missing line in an three view drawing. I looked at it and immediately saw where the line was missing so I drew it on the exam sheet. Then I saw another place where the missing line could be, and another, and another. So I drew up four answers that included 3D sketches of all four. The professor (who happened to be the worst professor of my college years) gave me zero points. I talked to him after class and he told me flat out that he wouldn't reconsider because I should have only included the obvious answer. That ticked me off (btw I will not get ticked off by anything anyone says about the crudder). I went to my advisor, he went to the Dean of Engineering and the three of us reviewed my exam with the professor. The Dean asked questions about all four of my drawings and concluded that they were all correct answers. He had taken the same exam 20 years earlier and between the Dean and my advisor had administered the test at least 200 times to over 4000 students and no one had come up with three of my four answers. The three of them did agree that one answer was the normal answer. I still don't know what the criteria for normal is. If I did I would have bought a Catalina instead of building an IC.

Cheating is a bit of a harsh interpretation given that I am not hiding anything about the crudder and the crudder has yet to hit the water. I bet all of us want the fastest legal boat we can make and we do that by adding material here, taking material from there until we think we have an advantage. Some of our collective ideas probably appeared a bit nutty on day one but by now are considered common practice. The first plank, carbon mast, gybing daggerboards included. The nuttiness is part of the fun of a development class.

If the crudder flies, it wouldn't be too difficult to convert uncruddered canoes into cruddered ones. So it won't make your IC obsolete.

#2507 eliboat

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Posted 08 August 2012 - 03:36 AM

My cheating comments were joking, if you had any doubts. I actually think the crudder is quite clever. I also think that superior boat handling can easily overcome differences from one boat to another. Where are you at with your boat at this point? Any chance we will see you on a Thursday soon?

#2508 JimC

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Posted 08 August 2012 - 08:23 AM

I'm not sure I entirely visualise the thing, but before you get into serious construction I suggest you let one of the class measurers see an isometric drawing of what you propose.

I'm not a class measurer, or even someone with any influence and position in the class at all, so what follows is strictly personal, nothing else... Rule writing is a difficult exercise, and its not possible to cover every possibility. On the other hand its very easy to issue a clarification later. I think its likely that a structure that was faired into the bottom of the hull and rigid with the hull would be looked at as part of the hull, detachable or not. If on the other hand its not faired into the normal water flow beyond the length limit then I doubt anyone is going to worry. So, if what you reckon is a good solution for the rudder system for you includes a rigid structure beyond the end of the hull, then keep it out of the water flow and I'm sure that will be fine.

The trouble with really ingenious means to evade the concept of the rules is that they kick up bad feeling. We all want to look at your boat/pictures of your boat and say, "hey, well done, that's a really good job, congratulations, can't wait to see it on the water" and not be sucking in breath between our teeth and thinking, or worse saying "you really shouldn't have done that, I suppose we're going to have to ban it".

Jim C

#2509 El Crapitano

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Posted 08 August 2012 - 03:24 PM

My cheating comments were joking, if you had any doubts. I actually think the crudder is quite clever. I also think that superior boat handling can easily overcome differences from one boat to another. Where are you at with your boat at this point? Any chance we will see you on a Thursday soon?


Your cheating comment made laugh and laugh again. My boathandling promises to be atrocious until I get some seat time. The boat is primed, and all parts of made except for a couple of replacement jib battens which won't take long to make. Topcoats and roofrack are on the agenda this weekend. After that its reattaching all the fittings and rigging up the lines. I will make every attempt to see you on a Thursday, are you referring to Bristol Yacht Club series?

I'm not sure I entirely visualise the thing, but before you get into serious construction I suggest you let one of the class measurers see an isometric drawing of what you propose.

I'm not a class measurer, or even someone with any influence and position in the class at all, so what follows is strictly personal, nothing else... Rule writing is a difficult exercise, and its not possible to cover every possibility. On the other hand its very easy to issue a clarification later. I think its likely that a structure that was faired into the bottom of the hull and rigid with the hull would be looked at as part of the hull, detachable or not. If on the other hand its not faired into the normal water flow beyond the length limit then I doubt anyone is going to worry. So, if what you reckon is a good solution for the rudder system for you includes a rigid structure beyond the end of the hull, then keep it out of the water flow and I'm sure that will be fine.

The trouble with really ingenious means to evade the concept of the rules is that they kick up bad feeling. We all want to look at your boat/pictures of your boat and say, "hey, well done, that's a really good job, congratulations, can't wait to see it on the water" and not be sucking in breath between our teeth and thinking, or worse saying "you really shouldn't have done that, I suppose we're going to have to ban it".

Jim C


Jim, the crudder is built, a topcoat of paint and it is done done. It will be used, legal or not, initially as I have no replacement and I desparately want to transition from workshop sailing to on the water sailing. The boat will be light too, I think. I need access to approved scales to dial in how much weight needs to be added. I have been using a 1920's vintage cow scale and while it is a nicely manufactured piece, I don't think modern sailors would trust it. Getting measured is a bit of a challenge because we have no local measurer.

I truly understand the challenges of rule writing. I was on the committee that rewrote the J/35 class rules and had to deal with all of the technical and people challenges that come with the job. I was also the class measurer for several regattas and there were always issues.

If the crudder endplate were out of the water flow, it would no longer function as an endplate and I would saw it off. The purpose is to be an endplate.

I doubt I have done anything ingenious. If I have, it would be a first. My expectation is that once I get sailing, I'm bound to learn how uningenius I have been.

No need for any of us to get bad feelings, we can resolve this. As I told John Kells, if I have to rebuild the rudder cassette and the tiller so be it.

IC sailors, you included, have been absolutely great providing advice and support.

#2510 Amati

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Posted 09 August 2012 - 02:17 AM

I must admit, finding out if what your doing is is legal a bit of an adventure. I felt liked I bugged the US measurer (1000 miles distant) so much over the internet tube system about rule interpretation he seemed to be telling me to build it and show up. But I must admit some of the reasoning he used came as a complete surprise to my tiny tiny painful swelling brain.

So I'm hoping even if I'm off by a few rules the guys will let me tag along. I realize I was taking up a lot of his time.

You are an inspiration, Meester Crap.

For what its worth, I'm looking at about a month out for trails of the proto. I'll post some sort of visual media, at that time, and enjoy the gestalt.

Paul

#2511 IC Nutter

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Posted 09 August 2012 - 03:21 AM

Crap,

From our description the crudder cassette looks like this:

Posted Image

which personally I don't have a problem with. But there is no rule which limits the maximum width of a detachable thing sticking out of the stern to 50mm, so if you allow the crudder, then you might have to allow something that looks like this:

Posted Image

which personally I would have a problem with.

#2512 FishAintBiting

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Posted 09 August 2012 - 04:13 AM

Crap,

From our description the crudder cassette looks like this:

Posted Image



With this first picture I would suggest building up the dance floor around where the "cRuddEr" is inserted in. If built correctly will handle the loads better and perhaps be more torsionally stiff.

Good luck,

Fish

#2513 IC Nutter

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Posted 09 August 2012 - 06:09 AM

With this first picture I would suggest building up the dance floor around where the "cRuddEr" is inserted in. If built correctly will handle the loads better and perhaps be more torsionally stiff.

Good luck,

Fish


The depth shown is probably not to scale. I don't know how deep Crap's transom is.

#2514 El Crapitano

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Posted 09 August 2012 - 01:57 PM

Crap,

From our description the crudder cassette looks like this:

Posted Image

which personally I don't have a problem with. But there is no rule which limits the maximum width of a detachable thing sticking out of the stern to 50mm, so if you allow the crudder, then you might have to allow something that looks like this:

Posted Image

which personally I would have a problem with.


Nutter,

Your pix show up as red X's on my screen, but I am going to take a guess at your point. That is that while my crudder overhangs the rudder by a reasonable 3/8" at the aft edge, if it continued aft by another foot or two, it becomes a problem. My rule interpretation is that the cassette has to be performing a rudder function along its entire length to be considered a rudder fitting or hardware. My cassette performs as an endplate along its entire length and that is a rudder function since it improves the performance of the rudder. A stretched cassette ceases to be a rudder fitting or hardware once it gets a bit past the aft edge of the rudder because it stops improving the performance of the rudder.




With this first picture I would suggest building up the dance floor around where the "cRuddEr" is inserted in. If built correctly will handle the loads better and perhaps be more torsionally stiff.

Good luck,

Fish


The depth shown is probably not to scale. I don't know how deep Crap's transom is.


My transom is roughly 3" deep at the centerline. I think there are IC's out there with svelter derrieres. I went deeper for the added floatation so the boat will be more forgiving if I get my weight too far aft.

The crudder seems to be structurally sound.

#2515 El Crapitano

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Posted 09 August 2012 - 02:48 PM

To clarify:

Attached File  Crudder Comparison.png   27.27K   33 downloads

#2516 Steve Clark

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Posted 09 August 2012 - 05:22 PM

Rule author here.
Let me make it unambiguous.
The "Crudder" is a legal arrangement.
It is a rudder fitting and is less than 50mm wide.
In fact it could be a meter long and it would be legal.
It would also be slow, because 50mm x 1000mm lined up with the flow isn't big enough to provide any meaningful bouyancey and will do nothing to improve the wave making resistance and will add wetted surface.
I question the merit of the little bit of end plate, which really doesn't have to extend beyond half chord to be effective.....but that doesn't make any difference, the option was considered when I wrote the rule and I determined that there would be no speed advantage to this fabrication. There are some structural advantages, which make hanging a rudder on a tiny stern easier, if one is so minded. The biggest benefit may be to allow the tiller to be just a bit longer and or to have just a bit more room to move your feet when all the way back in the bus.
That's why we wrote the rule this way!
Before we call you a genius however, I want to see how badly the stern and or cassette get mangled by running into something.
SHC

#2517 Steve Clark

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Posted 09 August 2012 - 05:45 PM

Posted Image


The rudder fitting has to be less than 50mm wide, so this arrangement would require overall length to the aft edge of the rudder.
If the aft edge of the rudder were forward of the aft edge of that big hull extending rudder fitting and one tried to argue that the hull boat aft of the rudder should be excluded from the LOA, I would take them aside and tell them they were very clever and engage in flattering banter about their talent and charm while Willy stomped the little cheating piece into the parking lot.

The goal of these rules is to allow people to creatively design and build boats that are enough alike that we can all sail together. The exercise is not to figure out how to build complex ways to build boats that are longer than they should be just to make the rule makers look stupid.

SHC

#2518 Del Olsen

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Posted 09 August 2012 - 11:52 PM

As to the legality of this IC part, in the first illustration the rectangular shaped "crudder" would pass the the letter of the rule.
However the "V" shaped piece of equipment in the second illustration would not pass, failing the "spirit of the rule" test.
So there is the ruling from the National Measurer and opinion from no less an authority than the Rule Author.
As an aside, I've been wondering when somone was going to push this particulat part of the envelope.
Should have chimed in earlier but have been away from the forms lately.
Will you be sailing by the Nationals in Mid Sept ??
Good Luck

Crap,

From our description the crudder cassette looks like this:

Posted Image

which personally I don't have a problem with. But there is no rule which limits the maximum width of a detachable thing sticking out of the stern to 50mm, so if you allow the crudder, then you might have to allow something that looks like this:

Posted Image

which personally I would have a problem with.



#2519 El Crapitano

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Posted 10 August 2012 - 09:39 PM

Attached File  Crudder.jpg   616.38K   99 downloads

#2520 El Crapitano

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Posted 10 August 2012 - 09:42 PM

Attached File  Progress.jpg   637.33K   88 downloads


I will be sailing in 2 weeks!

#2521 Del Olsen

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Posted 11 August 2012 - 03:00 AM

Just enough time for a test sail before putting her on the trailer for the Nationals in Richmond the weeekend of the 15 & 16 of Sept.

#2522 Steve Clark

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Posted 11 August 2012 - 01:37 PM

However the "V" shaped piece of equipment in the second illustration would not pass, failing the "spirit of the rule" test.

AND the 50mm width rule.

Personally, i'm not sold on the value of the bit sticking out the back.
The trailing edge of the rudder at that height is pretty strong, usually it's the tip part that gets chipped up.
And I wouldn't think that dragging that tail around would appeal to me.
Of course it all depends on how cool the roster tail looks.

I also think that in the event of a grounding, the bits are going to get as mashed up as any of the alternatives, so don't really think I would have done it that way.

BUT this is one of the nice things about ICs, you can exert your brain to come up with different solutions, which even if not better are YOURS.

I'm thinking there will be RI trailer headed to the Nationals. Room for some boats for those who want to get cold and wet in Richmond.
Space is limited so sign up now.
Divers wanted.
SHC

#2523 Big D

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Posted 12 August 2012 - 12:59 AM

OK so this Driver needs to charter a trusty steed for the nationals. Anyone? My truck and boat are in Ohio waiting for the HPDO in New York in October.

#2524 El Crapitano

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Posted 12 August 2012 - 11:00 PM

Well it appears that I may have acheived the crudder trifecta of slower, more vulnerable to damage and uglier. One trip through the saw could cure all, but not now.

I'm not going commit to a cross country journey until I gain some confidence in my boathandling. The last time I sailed in SF it blew 25+.

Two coats of topcoat:

Attached File  Topcoat.jpg   597.26K   130 downloads

#2525 Del Olsen

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Posted 13 August 2012 - 01:43 AM

Hey Crap,
Unless you're Usain Bolt, confidence is relative and somewhat over rated.
It's mid Sept and thou it can blow, it's much less likely to be nukeing.

What's the Tale of the Scale showing?
Keep us posted,

#2526 FishAintBiting

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Posted 13 August 2012 - 04:21 AM

Well it appears that I may have acheived the crudder trifecta of slower, more vulnerable to damage and uglier. One trip through the saw could cure all, but not now.

I'm not going commit to a cross country journey until I gain some confidence in my boathandling. The last time I sailed in SF it blew 25+.

Two coats of topcoat:

Attached File  Topcoat.jpg   597.26K   130 downloads


Holy Crap!

That looks great, though there is no way they won't know it was you over at the start

Enjoy,

Fish

#2527 El Crapitano

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Posted 13 August 2012 - 03:36 PM

Holy Crap!

That looks great, though there is no way they won't know it was you over at the start

Enjoy,

Fish


Thanks Fish. The plan is to blend in with the orange pin, or blind the race committee.

Del, I don't mind embarassing myself but I need to be capable of sailing out to the course and back without damaging anyone's boat, including yours. I have had fun sailing Lasers, windsurfers and big boats in nuclear conditions just need to learn the IC handling tricks.

The weight spreadsheet says between 2 and 5 pounds under, but the hull hasn't been weighed since it was in parts, and there is the question of cow scale accuracy. Light is good, after the first sail modifications may be required.

#2528 Del Olsen

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Posted 13 August 2012 - 04:58 PM

El Crap,
Embarassing yourself is part of the experience, sometimes it's more fun in the company of others on that same path. I have a laundry list of misadventures , from under engineered rudders to untested boats heading for the start line of a major race.
It's a good call to do it the right way and be prepared. If not for the Nationals the for the North Americans next year, I think they're scheduled to be in your corner of the country.
The Pix look good and if you're looking to add some lead , a really good job building. and no comments about orange peal paint jobs, Please
Cheers


Holy Crap!

That looks great, though there is no way they won't know it was you over at the start

Enjoy,

Fish


Thanks Fish. The plan is to blend in with the orange pin, or blind the race committee.

Del, I don't mind embarassing myself but I need to be capable of sailing out to the course and back without damaging anyone's boat, including yours. I have had fun sailing Lasers, windsurfers and big boats in nuclear conditions just need to learn the IC handling tricks.

The weight spreadsheet says between 2 and 5 pounds under, but the hull hasn't been weighed since it was in parts, and there is the question of cow scale accuracy. Light is good, after the first sail modifications may be required.



#2529 John K

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Posted 15 August 2012 - 04:50 PM

Rule author here.
Let me make it unambiguous.
The "Crudder" is a legal arrangement.
It is a rudder fitting and is less than 50mm wide.
In fact it could be a meter long and it would be legal.
It would also be slow, because 50mm x 1000mm lined up with the flow isn't big enough to provide any meaningful bouyancey and will do nothing to improve the wave making resistance and will add wetted surface.
I question the merit of the little bit of end plate, which really doesn't have to extend beyond half chord to be effective.....but that doesn't make any difference, the option was considered when I wrote the rule and I determined that there would be no speed advantage to this fabrication. There are some structural advantages, which make hanging a rudder on a tiny stern easier, if one is so minded. The biggest benefit may be to allow the tiller to be just a bit longer and or to have just a bit more room to move your feet when all the way back in the bus.
That's why we wrote the rule this way!
Before we call you a genius however, I want to see how badly the stern and or cassette get mangled by running into something.
SHC


Steve,

Thanks for helping put this to bed. I stand corrected.

John

#2530 Bill R

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Posted 17 August 2012 - 09:34 PM

Hi Guys,

I am new to the sailing canoe seen and have picked up NZL2 an old nethercott deisgn. I am slowly getting it uo to speed. Can you advise what size rudder is best for this design? As the one it came with looks a bit small and I think it may be a bit shorter than it should be.

#2531 Jethrow

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Posted 17 August 2012 - 10:47 PM

Hi Bill

Try asking here too... http://www.intcanoe.org/forum2/

I'm unsure about the Nethercotts but last one I saw did have a pretty small rudder. smaller than mine anyway

#2532 ICU2

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Posted 18 August 2012 - 10:32 AM

PM sent... about rudders and more RE IC's down under

#2533 JimC

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Posted 18 August 2012 - 09:38 PM

As the one it came with looks a bit small and I think it may be a bit shorter than it should be.

The under the boat (as opposed to transom hung) rudders typically look bloody ridiculously small. Part of that is the optical illusion of having no stock, and more of it is probably the extra efficiency of having effective end plating so ventilation is practically impossible if the boat is anywhere near flat, and yet more of it is probably the long lever between plate and rudder. But even allowing for all that mine still looks comically small and short to me yet still works.

So don't worry about it!

#2534 chrishampe

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Posted 18 August 2012 - 09:43 PM

The one hanging off the back of monkey is also small. Guess size really doesn't matter and its all in the way you wiggle it. ;-)

#2535 Bill R

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Posted 18 August 2012 - 10:33 PM

Thankyou gentlemen,


I shall make it a tad bigger than what I've got as its easy to chop some off, as opposed to add some on.

will let you know what sort of wiggle factor it has.

#2536 El Crapitano

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Posted 24 August 2012 - 02:54 PM

Hull 252 launched yesterday!

Before filling in the details, I need to give credit where credit is due. First to John Kells who has provided quality advice to me free of charge for the better part of a year. Yesterday he rolled up his sleeves and fixed numerous rigging problems when he could have rigged his own boat and gone sailing. Second to Steve Clark for providing a 3mm headstay to replace my undersized 1.2mm one before it broke. Steve also fixed my riveter. It wasn't really broken so fixing it was easy for him. Willie helped too, offering Steve's 40# Big Daddy riveter to install a 1/8" pop rivet. Willie really did help, joining in with John on the rigging. And thanks to Kim for dinner afterwards.

I arrived at Point Farm an hour early to perform boom surgery with the shock cord that can't be bought where I live. And to rig. I am a total newby and rigging takes me forever, partly because I take things apart at the wrong places. I didn't forget any parts, which helps, or any tools, which also helps. The rack on the car held both coming and going. I'm going through the short list of things I did right. I was so slow at rigging that at one point Steve, Willie and John were rigging it. I was helping, sort of.

Eventually 252 was ready. Willie grabbed a bottle and a camera. While Willie focused the camera, Tristan the dog snuck into the picture and dropped a deuce. Uncanny. The cork popped and the boat and owner were sprayed with champagne. I had to cough up a name. Kraptonyte came out, but maybe Deuces would be more appropriate.

Then I launched. Steve pushed me into the Kickemuit with John showing me where to go to not hit bottom. For the first minute or two things were seemingly ok. I sat out on the seat a bit, main and jib were drawing. I trimmed them a bit. The carriage slid forward on its own so I need to add a brake. Then I sailed into a lull and scrambled to leeward and even grabbed the boom for a pump but to no avail. I slid off the boat and stood on the bottom and rerighted. After sort of getting going again I had to tack and went back in. Another reright but this one was different, there was a bit of a crack noise. After that there was more crack noise than sailing. The crack noise was coming from the crack in the daggerboard. I made the board almost 4 years ago out of carbon over a spruce core. I think I put enough carbon on the board but sanded too much off and that was the problem. The sail was over. All that was left to do was to walk back across the Kicke to the launch ramp, boat in tow.

This morning I update my to do list. I've been working down this list since May.
Attached File  Worklist.PNG   448.58K   35 downloads

#2537 JimC

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Posted 24 August 2012 - 03:53 PM

he crack noise was coming from the crack in the daggerboard.


Oh how very irritating. Congrats on getting on the water, if only briefly.

I'm reminded of an incident at a champs in another class some years ago

Previous evening in bar: "I can't understand how [redacted]'s foils haven't broken. They're exactly the same layup as my ones which broke"
Next day on race track: "crack"

#2538 ortegakid

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Posted 24 August 2012 - 05:28 PM

I had the same problem at a leukemia cup reggatta, seems when you don't stand on board much you don't know how easily it will break! Better to over build than be lightest.

Congrats!, now pix plz!

#2539 killerken

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Posted 25 August 2012 - 02:49 AM

hey Cats,
my Canoe, Can 39 is for sale.
for those who don't know it, this is the prototype Super String Theory, built by Chris Maas from which the molds were made for the SST boats that Chris is currently building. it is a proven fast boat, faster than the helm.
the sails are very good shapes in very good condition, not having much time on them. main by Graham Herbert, Kinder jib.
mast is the latest high modulus van Dusen.
daggerboard by Bieker, in a gybing cassette, swing up rudder by Chris.
most lines Maffioli
housed in a very light, very aero trailer, which keeps the boat dust free in the most horrific road conditions. the trailer has custom made soft springs and new hubs carrying balanced 12" wheels and radial tires.
I'll send fotos by email, until I figure out how to get em on this site.
not at all sure it is appropriate to advertise my boat in this way.
cheers, Kenny

#2540 killerken

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Posted 25 August 2012 - 02:52 AM

a contact email is agtfree1@hotmail.com
I can meet halfway, or do a full delivery if fuel costs are covered.
price is $15,000 Cdn

#2541 eliboat

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Posted 25 August 2012 - 12:03 PM

We need pics of the boat and of Tristan pooping.

#2542 FishAintBiting

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Posted 25 August 2012 - 12:51 PM

a contact email is agtfree1@hotmail.com
I can meet halfway, or do a full delivery if fuel costs are covered.
price is $15,000 Cdn


Out of curiosity- Have you paid SailingAnarchy for an advertisment?

#2543 El Crapitano

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Posted 25 August 2012 - 03:23 PM

Congrats!, now pix plz!


Here's a picture of my crack:













Attached File  Crack.jpg   100.13K   27 downloads

We need pics of the boat and of Tristan pooping.

Willy has them.

#2544 JimC

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Posted 25 August 2012 - 06:07 PM

That's really unusual - can't offhand remember seeing a board fail with lengthways cracks like that.

#2545 killerken

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Posted 25 August 2012 - 07:41 PM


a contact email is agtfree1@hotmail.com
I can meet halfway, or do a full delivery if fuel costs are covered.
price is $15,000 Cdn


Out of curiosity- Have you paid SailingAnarchy for an advertisment?

no! didn't know they had a for sale section! if so, I'll check it out.

#2546 FishAintBiting

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Posted 25 August 2012 - 07:58 PM



a contact email is agtfree1@hotmail.com
I can meet halfway, or do a full delivery if fuel costs are covered.
price is $15,000 Cdn


Out of curiosity- Have you paid SailingAnarchy for an advertisment?

no! didn't know they had a for sale section! if so, I'll check it out.


To help you out, try this link http://www.sailingan.../classified.htm

Good luck with selling it.

#2547 killerken

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Posted 26 August 2012 - 02:05 PM

sorry about the gate crashing folks, I found classifieds under 'features'. will put an ad in there.
Kenny

#2548 Ncik

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Posted 27 August 2012 - 05:45 AM

Well it appears that I may have acheived the crudder trifecta of slower, more vulnerable to damage and uglier. One trip through the saw could cure all, but not now.

I'm not going commit to a cross country journey until I gain some confidence in my boathandling. The last time I sailed in SF it blew 25+.

Two coats of topcoat:

Attached File  Topcoat.jpg   597.26K   130 downloads


the wall posters are nice ;)

#2549 killerken

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Posted 28 August 2012 - 02:17 AM




a contact email is agtfree1@hotmail.com
I can meet halfway, or do a full delivery if fuel costs are covered.
price is $15,000 Cdn


Out of curiosity- Have you paid SailingAnarchy for an advertisment?

no! didn't know they had a for sale section! if so, I'll check it out.


To help you out, try this link http://www.sailingan.../classified.htm

Good luck with selling it.

ad in in the classifieds soon, I hope. paid for...

#2550 John K

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Posted 29 August 2012 - 05:00 PM

Just a reminder that the deadline for HPDO registration without incurring the $40 late fee is September 1.

Looking forward to seeing Big Dave & others.

By my count we could easily have eight boats on the line.

Who is in:

Steve
Willy
Dave
Bill
Big George
Eli
El Crapitano
Big Dave
Robbie

#2551 Steve Clark

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Posted 31 August 2012 - 02:55 PM

The Yacht:
Attached File  Kraptoniote.JPG   228.95K   119 downloads
The Dog:
Attached File  Tristan_edited.JPG   168.68K   147 downloads
The Toast:
Attached File  El Crapitano 3.JPG   271.06K   155 downloads
The Launch:
Attached File  Satisfaction.JPG   149.14K   145 downloads

Well done all!
SHC

#2552 c maas

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Posted 31 August 2012 - 06:38 PM

NICE!

#2553 eliboat

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Posted 01 September 2012 - 03:14 AM

I'm in

Just a reminder that the deadline for HPDO registration without incurring the $40 late fee is September 1.

Looking forward to seeing Big Dave & others.

By my count we could easily have eight boats on the line.

Who is in:

Steve
Willy
Dave
Bill
Big George
Eli
El Crapitano
Big Dave
Robbie



#2554 rocknodster

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Posted 12 October 2012 - 10:14 PM

After a long winter off, playing Ice Hockey mainly, it is time for the IC to hit the water again. If it all goes well I'll post pics, if not then we'll all know that my lack of sailing and maintenance this winter may not have been the best approach :D

#2555 TalonF4U

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Posted 16 October 2012 - 04:52 AM

Hey, HPOD report--who's on it?

Nationals... Del vs Me... I'll give my report when I hear about yours.

Let's find some regattas for the upcoming year and make some commitments, shall we?

#2556 MonkeyDC308

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Posted 17 October 2012 - 08:51 PM

I am working on some new hull ideas and wanted to compare the stability of them compared with my previous efforts. Not sure what the best approach is. I had done what I thought was a far more stable design but when I looked at how the center of boancy moved when I healed it there was very little difference to Dragonfly although the new design was max width, any suggestions?

#2557 Amati

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Posted 17 October 2012 - 11:53 PM

Image?

#2558 IC Nutter

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Posted 18 October 2012 - 01:57 AM

I am working on some new hull ideas and wanted to compare the stability of them compared with my previous efforts. Not sure what the best approach is. I had done what I thought was a far more stable design but when I looked at how the center of boancy moved when I healed it there was very little difference to Dragonfly although the new design was max width, any suggestions?


If you still have the minimum waterline beam but flare the topside to maximum beam, it may not alter the stability much. But it does give you more dance floor, which gives you a greater margin for error. The problem with a minimum beam hull, coupled with the minimum freeboard restriction, is that when the boat heels you quickly reach the point where standing on the gunwhale is not enough to right the boat i.e. your centre of gravity is very close the transverse centre of bouyancy. Making the deck wider just allows you to stand further outboard. The boat can then heel further before you reach the point of no return.

If you want to actually make the boat more stable, you have to increase the waterline beam and sacrifice wetted surface area. There's no way around it.

#2559 MonkeyDC308

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Posted 18 October 2012 - 07:16 AM


I am working on some new hull ideas and wanted to compare the stability of them compared with my previous efforts. Not sure what the best approach is. I had done what I thought was a far more stable design but when I looked at how the center of boancy moved when I healed it there was very little difference to Dragonfly although the new design was max width, any suggestions?


If you still have the minimum waterline beam but flare the topside to maximum beam, it may not alter the stability much. But it does give you more dance floor, which gives you a greater margin for error. The problem with a minimum beam hull, coupled with the minimum freeboard restriction, is that when the boat heels you quickly reach the point where standing on the gunwhale is not enough to right the boat i.e. your centre of gravity is very close the transverse centre of bouyancy. Making the deck wider just allows you to stand further outboard. The boat can then heel further before you reach the point of no return.

If you want to actually make the boat more stable, you have to increase the waterline beam and sacrifice wetted surface area. There's no way around it.


Thanks, you have guessed where I was going with that, I have taken Dragonfly's under water shape and flared from that, which worked out as just extending the small chine I have, then I nipped in the bow a bit to end up with .. well I would have attached a photo but I am not sure how, the forum has changed since I last posted an image!

#2560 Amati

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Posted 18 October 2012 - 08:26 AM

Probably doesn't help what with your design's evolutionary approach, but as a very simple example, a max beam square chine flat bottom double end hull with a lowish prismatic, while having around 38 sq ft of wetted surface upright can get down to 28 sq ft of wetted surface at 10-15 degrees of heel. Without foils. Buoyancy moves sideways a lot. Kind of a Formula board with streamlining. :) 2.6" of rocker. A lot of square feet overall for the whole hull. Hard to get it light? Numbers above based on displacement about 285 lbs. with sailor.

#2561 MonkeyDC308

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Posted 18 October 2012 - 12:38 PM

Attached File  wide-october2012.png   444.28K   45 downloads

#2562 MonkeyDC308

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Posted 18 October 2012 - 12:48 PM

Attached File  dragonfly sections.png   352.15K   33 downloads
Dragonfly's sections

#2563 Amati

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Posted 18 October 2012 - 04:07 PM

If you slice off the sides longitudinally, say 2" in from the gunwales, on Dragonfly, and leave them in place (like taking out the mid section of the hull and leaving the sides of the hull looking like a skinny catamaran, and then do the same with the green hull at the same point out, and then look at the resultIng 'hulls' from the front or back, with the waterline in place, I think you'll see what's going on, especially if you're looking for initial stability (like when tacking?). It would help even more if you can rotate around the longitudinal axis with the waterline showing as influenced by the changing volume.Maybe if you made the inside gunwales of the green boat thicker, so you could heel into some volume, while leaving a nice low dance floor. That would be like making the hulls of the skinny catamaran more floaty, instead of water coming over a skinny edge and into the boat easily. Would just take some longitudinal strips of foam temporarily glued down on the inside of the rail to test. Given the skinny nature of the green boats rail, you might even add some floatation a bit lower at progressive angles of heel by doing this?

#2564 Amati

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Posted 18 October 2012 - 06:54 PM

I meant to do this on a computer, with design software.

Oops.



#2565 JimC

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Posted 19 October 2012 - 12:30 PM

Thanks, you have guessed where I was going with that, I have taken Dragonfly's under water shape and flared from that,

I was looking at the mould (and the Maas and Morrison) yesterday and I really don't know how you're going to get any great difference in stability without a major change in the underwater shape.There doesn't seem to me to be enough volume available low enough down for flare to make much difference.

One of the things that bemuses me is that, from what I can gather, historically minimum beam Canoes have not necessarilly been regarded as quick - the Nethercott was some way off minimum beam and so, of course, were Uffa's boats. However since we've gone back to the box rule everyone has gone minimum beam, and when I draw stuff on the PC and look at the numbers they are yelling at me that thin is the way to go.

So what's changed? Maybe I should push drawings from the 1930s onto the box and see what they tell me? One big thing of course is that rigs must weigh a fraction of what they used to, and that must have a big effect.

I wish I was brave enough to build a wide boat and see what happens, but the trouble with radical experiments is that, unless you are a front of fleet sailor or can persuade one to sail your design regularly, you really have no way of finding out whether the concept works or not because the boat is such a small part of winning races, and even were I fit I just don't steer boats at the required talent level.

#2566 IC Nutter

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Posted 19 October 2012 - 01:35 PM

I don't think a wide hull is ever going to be faster than a narrow one. The numbers aren't wrong. If you are really serious about winning, build the narrowest hull you can with the lowest wetted surface and learn to get it around the course.

But for those of us who are less serious about winning and/or haven't got the time or the will to put in the necessary practice (or who are just getting old and worn), there is the option to go for a wider hull. If that is enough so that you can get around the course upright more often, the result may be an overall improvement in your personal performance, not to mention greater enjoyment of the sailing experience than if you spend most of it swimming. A wide canoe may not be super quick compared to a narrow canoe, but it sure beats a Laser, if not just about anything else!

#2567 Steve Clark

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Posted 19 October 2012 - 04:25 PM

The difference between now and then is the weight of the rigs and the proficiency of the sailors.
Read the reports if Uffa and you hear things like " fast but too hard to sail."
Getting pounds out of the air has certainly changed the game, but so has the expertise of the sailors.
We all sail things that would have been inconceivable 50 or 60 years ago because we have gradually learned how.
The Nethercott was a conservative design from the mid to late 1960s. It predates a Laser.

I think more important than the stability is the rate of change. A bit more flare, I think, will slow the roll rate and a bit more beam on deck will allow more righting moment to be applied before committing to the seat. Both may be worth it making the boat easier to sail at full potential even if that potential is slightly lower than the minimum beam boat.

I wonder if a boat with enough deck beam to accommodate existing Nethercott seat carriages wouldn't be a good idea.

On the other hand, put the time in and figure out how to sail the skinny one is a pretty good strategy. It's not like going sailing on an IC is unpleasant.
SHC

#2568 JimC

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Posted 19 October 2012 - 05:03 PM

I wonder if a boat with enough deck beam to accommodate existing Nethercott seat carriages wouldn't be a good idea.

Andy and I were mulling over that too yesterday...
I was looking at the black needle taking shape and wondering if I could have hacked it even if other factors hadn't intervened.
I've certainly been thinking a bigger dance floor ought to be beneficial, but, as I've discovered with my fat stern Nethercott, you need then more freeboard to keep draggy bits out of the water if you heel, so then you've got more structure and weight, and several factors are going in the wrong direction.

#2569 ICU2

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Posted 20 October 2012 - 02:41 AM

I wonder if a boat with enough deck beam to accommodate existing Nethercott seat carriages wouldn't be a good idea.

Andy and I were mulling over that too yesterday...
I was looking at the black needle taking shape and wondering if I could have hacked it even if other factors hadn't intervened.
I've certainly been thinking a bigger dance floor ought to be beneficial, but, as I've discovered with my fat stern Nethercott, you need then more freeboard to keep draggy bits out of the water if you heel, so then you've got more structure and weight, and several factors are going in the wrong direction.


From Memory Scarlet Ohara used a nethercott plank and carriage and stay base and looks fast :)

#2570 Amati

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Posted 22 October 2012 - 09:40 PM

Rule Question-

It's been hard for me to see in pics-

If you were to take the max fullness stern at 1/2 angle 45 degrees, does the intersection of resultant straight stern lines with the gunwale have to be radiused at 4" in planform view?

It looks like the stern can be a 90 sharp edge in profile view (like a hard chine) as it seems the resulting stern surface, going forward, vertically, can exist as if it were cut off as clean face on the angle from the stern to the point where it meets the gunwale coming back?

Do the 2 overlap? I can see a gunwale angling suddenly down to the stern in profile being an angle, but in planform it would have to be Radiused?





#2571 IC Nutter

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Posted 23 October 2012 - 01:11 AM

Rule Question-

It's been hard for me to see in pics-

If you were to take the max fullness stern at 1/2 angle 45 degrees, does the intersection of resultant straight stern lines with the gunwale have to be radiused at 4" in planform view?

It looks like the stern can be a 90 sharp edge in profile view (like a hard chine) as it seems the resulting stern surface, going forward, vertically, can exist as if it were cut off as clean face on the angle from the stern to the point where it meets the gunwale coming back?

Do the 2 overlap? I can see a gunwale angling suddenly down to the stern in profile being an angle, but in planform it would have to be Radiused?


Yes, it has to be radused in planform. I think it's a 60mm radius, which is quite small. You could probably build it as a sharp corner then make it fit the rule with filler and sandpaper. Or build small gunwhale over the corner and radius that.

#2572 JimC

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Posted 23 October 2012 - 02:31 PM

Yeah, the radius is not hard to achieve. Indeed when I put the full stern on my Nethercott I clean forgot about the existence of the rule, but when I'd checked discovered that I'd complied with it anyway just rounding off the wood capping/gunwhale that protects the edge of the ply deck.

#2573 Amati

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Posted 23 October 2012 - 02:58 PM

So, in practice, if the corner (which is the side of the hull) was, say, 4" in thickness vertically, the rule would be met by rounding the gunwale stripping on the top of it? And leaving the corner intact? That seems agreeable....

#2574 Andy P

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Posted 23 October 2012 - 05:03 PM

Yes the projection must have the radius etc, but it can be gunwale or bottom or sides.
On the Maas boat I'm doing, there is a flat panel at ~ 45° to vertical, so the projection of the transom is gently curved due to the bottom curvature, and a bit at the chine I'm going to have to fiddle with to meet the radius - but it's only a tiny bit in reality . A CD is exactly the right size for checking this radius.

#2575 Amati

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Posted 23 October 2012 - 08:27 PM

I knew those cd blanks I have littering my basement would come in handy......


Throw them away indeed. Humph.

Thanks guys.

#2576 Amati

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Posted 12 November 2012 - 07:53 PM

Pictures of 'A Kinematic Sculpure of Franks Brain as a Young Man". Apologies to the Betwaite Clan and James Joyce.

She's a 14' proto. Mast broke before we could get sailing fotos. Mast too stiff. Luff too round. Crunch.

end view- the easiest way to explain her is that she's a Proa without the little hull. wind always comes from the end of the seat to where it is fixed.

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reasons

never have to go under the sail or boom, harder to blow a tack/jibe

una sail setup is just too freakin' big and heavy, so why not use it to balance things rather than the opposite. you will notice the mast foot is on the lee edge

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my idea of leaving the mast foot on the mast track (shown), to move the sail CE, was floppy and uncontrollable. I removed it and fixed the mast foot in the middle, but still over by the lee. You'll see that in other shots.

a boat in balance is faster is my idea, like a windsurfer

mast rake can be set for conditions- rake is steering, so it's automatic. I use lines (orange lines) to move the sail laterally

only one foil needed, less drag. the foil moves on a track and is locked in place by water pressure laterally and longitudinally so the CR is in a more advantageous place. I kind of works. A beefier track, or multiple tracks may be better. It would also be fun to control the position of the foil longitudinally with a line- use moving the sail around as a gross control, moving the foil as a fine control.

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It looks like pic memory is getting balky, so I'll continue in a separate post-

#2577 Amati

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Posted 12 November 2012 - 08:14 PM

The foil is a bidirectional, developed by Tom Speer. It should have the same characterisitics as a NACA 0012. Might need a trip though. Phils foils made it.

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I didn't have enough ceiling height to attach the mast and sails, so I added a stick in approximately the righ place, on top of the mast foot, which is red. it isn't pointing up enough, but I hope it gives the idea. The spar that is finished meets the mast/sail at the wishboom, and is attached to the seat. there is a parallel line to the spar to take the loads away from the seat. There are a lot of goosenecks on this canoe. :) The idea is to use the seat for support and take twisting loads off of the hull as much as possible. These supports are all inside the sheer lines, so I hope that's legal. ?

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Seat position swivels, and is controlled by the black lines, which also limit seat movement up and down. The lines can be released enough so the mast can lie on the water like a windsurfing mast, while the seat remains vertical, making it a lever to uphaul the mast. I'm using wax for the top of the seat structure. Doesn't work very well. If I do another one, Ill use the Star Boat Vang setup that Harken has. It needs minimum 24" of radius, which works with the proa setup, since you don't need the circular traveller going across the hull, so wider hulls are easy.

Seat positions:

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I'll move to a separate post so I don't overload things

#2578 Amati

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Posted 12 November 2012 - 08:37 PM

Last one-

More seat details. the one fitting outside of the sheer is the one underneath the seat outboard, which is there to keep the mast lines from falling in the water. (I know it's backwards, but I haven't got around to fixing that- another idea that didn't work...) I know knots would have more purity, but cleats are so nifty.

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and what I ultimately want to do with the seat

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The obligatory shot of the dog.

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I'm hoping my use of the seat is in the spirit of Paul Butler.

Anyway, I'll know more when this melts

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sometime in March, and I can go sailing. That is my Zen displacement tank. Pity it's out of doors.

So, oh wise ones, assuming it was life size, is it a legal canoe? To some extent, whether I move past this one will depend on some guidance. On the other hand, if I can develop it so it's easy to sail, I just might have that sit down windsurfer Ive been nattering on about. And then I could attach the boom support spar to the moving seat, and incline the sail over me. It is a direction the class might consider. Spirit of development and all.....

If any of you would like additional pics or descriptions, please ask. I might add this has all been done with wood, Titebond #, some bronze ring nails, SS and bronze scews. I think the hull weighs ~40 - 45 lbs, but my scale is ancient and suspect. Whether it's strong enough for anything but light airs?

Opinions please.

Paul

#2579 IC Nutter

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Posted 13 November 2012 - 02:50 AM

Well Paul, If nothing else it's a work of art! I'd like to see it with the rig in place. I'm glad you're doing this so that if it doesn't work, I can cross it off my list of silly ideas to try ^_^ . I suspect that controlling the rig may be a challenge in a decent breeze.

I do think you need to beef up the foil support. Two tracks would be a good idea, or at least a rubbing strip lower down the hull topsides, where the bit of blue foam is (I guess you are already considering this). A sliding dagger case maybe?

I don't see why something like this couldn't be made to measure in as an IC. I don't think it will ever be faster than a 'real' one though because the hull is compromised to travel in both directions and you will always loose ground on tacks an gybes verses a competent 'normal' helmsman. As a proa fan myself however, I like the idea and commend your efforts. Looking forward to the video.

Mal.

#2580 MonkeyDC308

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Posted 13 November 2012 - 01:49 PM

Hi Paul
No idea if it measures or not, but very intresting, the steering sounds like the same concept as simon had on "bootiful", a speed sailing craft of a few years back, never quite got going as it should have done but it did work, there were winches that worked on peadle power that moved the rig up and down the hulls, with just a fixed skeg at the back. Simon taught me to sail a long time ago and I helped him on this project and a few other bits and peices.
Attached File  speed-1.jpg   31K   63 downloads

#2581 Amati

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Posted 13 November 2012 - 05:45 PM

Well Paul, If nothing else it's a work of art! I'd like to see it with the rig in place. I'm glad you're doing this so that if it doesn't work, I can cross it off my list of silly ideas to try ^_^/> . I suspect that controlling the rig may be a challenge in a decent breeze.

I do think you need to beef up the foil support. Two tracks would be a good idea, or at least a rubbing strip lower down the hull topsides, where the bit of blue foam is (I guess you are already considering this). A sliding dagger case maybe?

I don't see why something like this couldn't be made to measure in as an IC. I don't think it will ever be faster than a 'real' one though because the hull is compromised to travel in both directions and you will always loose ground on tacks an gybes verses a competent 'normal' helmsman. As a proa fan myself however, I like the idea and commend your efforts. Looking forward to the video.

Mal.


Thanks Mal, I have tossed around tacking/gybing speed, and if everything is automatic when shunting, I think I'd be in the middle of the game, given the amount to do when tacking an IC. There is a vid around starring a French RC proa shunting automatically, and it is instantaneous, so the main loss would be to the glide of a normal IC through the wind unpowered. If there is an advantage, it would be in stronger winds (?). Whether an asymmetrical section LB would be a positive? It seemed to me that a longitudinally symmetrical hull might have more planing area, a flatter run aft, a more gradual outline to the stern, and fewer handling vices. Whether these would be faster, a wash, or (horrors) one of those silly ideas (who said that?) that like a 2 iron whispers "do something glorious" awaits my determination, I suppose.

The problem with the foil support is how to figure the stress on the fitting to the hull. I was defining the CE of the foil at about half span, and the weight on that point at 280 lbs, which would come out at about 560 foot pounds on the traveler car which is near it's SWL, but even in 2k TW things were deforming alarmingly, which is why I glued the XPS on the side which helped a lot. How much lateral pressure are you assuming at the DB support in an IC hull? The XPS helped, but the long strip had a lot of friction on the shunt, and it's a testimony to liquid nails that the block side is still there. It's unclear to me that a protective strip on the outside of the hull would legal. A <1mm strip?

Oh, and the foil track(s)need(s)to be at least 2' longer.

Paul


#2582 Amati

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Posted 13 November 2012 - 06:51 PM

Hi Paul
No idea if it measures or not, but very intresting, the steering sounds like the same concept as simon had on "bootiful", a speed sailing craft of a few years back, never quite got going as it should have done but it did work, there were winches that worked on peadle power that moved the rig up and down the hulls, with just a fixed skeg at the back. Simon taught me to sail a long time ago and I helped him on this project and a few other bits and peices.
Attached File  speed-1.jpg   31K   63 downloads


Bootiful is always on my mind. I have enough track to do a similar support /steering setup (with spars) but the stumbling block for me is raking the rig on the fly, given the balance challenge the seat provides. Maybe I'm too preoccupied with that. With the sliding LB, the foil can either be a centerboard or a skeg, depending on placement.

Did you sail on Bootiful?

Paul

#2583 Amati

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Posted 13 November 2012 - 07:29 PM

Shunting fast with an RC proa:

Check out this video on YouTube:



Not French, but James Brett design, NZ

Check out this video on YouTube:




Sent from my iPad



Sent from my iPad

#2584 El Crapitano

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Posted 13 November 2012 - 09:50 PM

Quite unexpected.

It may run afoul of the no outriggers outside of the sheer rule.

The ability to get in front of another boat and apply the brakes hard could be a game changer.

Considering that you could drop your rig on my head will keep me on my absolute best behavior.

#2585 Amati

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Posted 13 November 2012 - 11:25 PM

Quite unexpected.

"It may run afoul of the no outriggers outside of the sheer rule."

-That one, I must admit, is a mystery wrapped in an enigma. When heeling? With the mast lying on the water?

"The ability to get in front of another boat and apply the brakes hard could be a game changer. "

-I like to think Manfred is smiling, but just a bit.

"Considering that you could drop your rig on my head will keep me on my absolute best behavior."


:)

#2586 IC Nutter

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Posted 13 November 2012 - 11:26 PM

It's unclear to me that a protective strip on the outside of the hull would legal. A <1mm strip?

Paul


Any rubbing strips or track supports would have to satisfy the 1m transverse tape rule at the measurement station (probably at midships in the case of a shunting hull). So if you have a flat bottom, 750mm across the chines, any protrusion on the topsides would need to be at least 125mm above the chine. Not to onerous. The rubbing strip or support at each end would also have to be faired back into the hull to satisfy the planform shape rule, also not a big deal.

The CE of the foil will be at about 25% back from the LE, regardless of it being symmetrical fore and aft. But your biggest issue is the moment due to the span of the foil. I think you definitely need two support points. The further apart you can space the supports, the lower the loads will be, and more importantly, the less the friction will be for moving the foil fore and aft. For spacing, think in terms of the depth of a CB case or rudder pintle spacing. I really think you need two tracks to reduce the friction as much as possible. You also need to consider the stresses in a backwind situation.

I'm assuming that any device that runs on the tracks and supports the foil can be counted as a rudder fitting and won't contravene the rules.

#2587 Amati

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Posted 14 November 2012 - 12:16 AM

Thanks Mal, I was hoping foil track might be considered a rudder fitting, and I agree, 2 tracks are necessary. I'm wondering if 3 cars, two on top, one on bottom might be a good idea. The 4" and 11" rule is handy!
Paul

#2588 Jethrow

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Posted 14 November 2012 - 12:19 AM

Nah Paul, forget about the rules. I just love it when someone has the balls to build some of their ideas. Just go out and have some fun with it. I'm not sure about tacking but shunting would be quicker than some of my gybes. :P

#2589 IC Nutter

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Posted 14 November 2012 - 01:07 AM

I'm wondering if 3 cars, two on top, one on bottom might be a good idea.
Paul


Yes, I think that will be necessary, otherwise it will bind up.

#2590 IC Nutter

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Posted 14 November 2012 - 01:33 AM

Paul,

It would be nice to combine your sliding foil with something like my easy shunting crab claw rig www.youtube.com/watch?v=nF6xC2rUU9w such that with a single continuous line you could slide both the rig forward and the foil aft (and vice versa) at the same time for steering.

#2591 Amati

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Posted 14 November 2012 - 02:55 AM

Paul,

It would be nice to combine your sliding foil with something like my easy shunting crab claw rig www.youtube.com/watch?v=nF6xC2rUU9w such that with a single continuous line you could slide both the rig forward and the foil aft (and vice versa) at the same time for steering.


Mal, that is trick! I have a lot of affection for the crab claw, having spent much time with one put together by my dad. It will have to wait in line after (dare I say it?) a dipping lug (a strange obsession), and most likely a fathead something or other. Any data on VMG upwind with the claw?

#2592 IC Nutter

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Posted 14 November 2012 - 03:50 AM

Any data on VMG upwind with the claw?


I'm not suggesting using a crab claw sail as such. The crab claw has some interesting properties, but outright efficiency is probably not one of them. Below is a photo of the model I built to test the rig. It used a fat head style sail....

Attached File  TrpezoidProaUpwind2.jpg   118.65K   32 downloads

#2593 Amati

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Posted 14 November 2012 - 03:56 AM

Wow. I can feel my brain expanding. Very Nice.

I really need to learn to make my own sails.

#2594 El Crapitano

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Posted 20 November 2012 - 07:18 PM

My choice of locations for a breather hole in my hole was particularly uninspired. It's at the forward edge of the slot that my centerboard anti-gybe brake slides in. Any water at the forward edge of the cockpit can find its way in there easily. While water can get there easily I can't. What was I thinking?

Do I really need a breather hole?

If I do need one, where does it go? Given the low freeboard, I'm not sure if there is a dry location for it. Inverted orientation needs to be considered.

#2595 Amati

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Posted 20 November 2012 - 08:10 PM

Does rule 4g (2 holes only breaching the hull) preclude a hole for an unstayed mast?

Or breathing holes now that crapitano mentions it.......

Paul


#2596 Andy P

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Posted 20 November 2012 - 09:15 PM

Only if it goes all the way through... - and out the other side :wacko:

#2597 JimC

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Posted 20 November 2012 - 10:00 PM

If I do need one, where does it go?

You do need something. Boats taken from cold water to hot sunshine change temperature a lot. Just above deck level in the front bulkhead ought to work. On my boat the breather is into the mast stump from inside the foredeck, and then out through the base next to the deck. I reckon that just above dance floor level on the back of the foredeck is pretty much never immersed.

#2598 Steve Clark

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Posted 21 November 2012 - 02:58 PM

Breather holes are nice.
A little Goretex over a hole is a pretty elegant solution for letting air in and out but stopping actual water. Find an old garment on itis way out and steal a bit.
Another solution is to locate the hole high in the bulkhead but put a tube on the inside that goes all the way down to the keel. This way one end is always above the waterline.
SHC

#2599 Amati

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Posted 24 November 2012 - 01:52 AM

Does the foredeck in plan view need to be curved, or can it look like an inverted V?

can the unstayed mast partners be the top of an an exposed tripod, or quadpod? Straight or curved?

Or does that violate the no holes all the way through rule?

If you find yourself asking why, the answer is Starling Burgess. Kind of.

Well, that and the mast base of Paul Bieker's 'Rocket Science'....

Without windows.

Paul

#2600 Andy P

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Posted 24 November 2012 - 12:55 PM

The deck profile must be a continuous line, convex, concave or straight sections are OK with limiting radii at junctions, and only one concave section per side of a limited amount.
The Maas boat I'm building is pretty much - from the stem - straight, small hollow just in front of the shrouds, long straight section for the seat track, and short curvy bit to the aft pointy end.
Holes can't go through the hull ( apart from board and rudder ), so a mast-gate hole is OK.
Read the rules for the details ;-)




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