This thread is a bar of solid gold for many reasons.
Hi cougar,
not so fast I still need a little more time to verify the shadows against the water line. I need to do that because I met already some discrepancies with other drawings.
For sure is a beautiful looking hull, but it may be necessary to modify the keel bottom for the reasons explained on previous post.
Cheers
ClaudioD
Cougar: Check out the J-Class model yacht site. John Hanks sells plans for Endeavour II for the 1/16 scale…a good drawing with lots of sections. http://www.officialjclass.org/plans_and_drawings.htm or contact him.
A low resolution picture of the plan is here: http://www.rcgroups.com/forums/showthread.php?t=1271041&highlight=endeavour+ii
Breakwater: I will be cautious if and when I present a new proposed class. New classes can be both good and bad, certainly all of the dinghy classes in the 70’s with the introduction of GRP hulls got a lot of people sailing, but now is the aftermath with many good boats not able to bring enough people together. Development classes, rule classes and one designs all have their followings, but also have their problems.
However: I see that there are problems that Claudio has fitting a metre rule boat to a fixed waterline…older, longer boats will be at a disadvantage with water line, displacement, and draft than the shorter modern boats. It looks like 12 metres ranged from 72 feet to 63 feet. This problem is why I suggested a scaled approach to racing metre rule and J-class boats. Nevertheless, I think what Claudio is trying to do is great, and I think these boats may not be super fast, but they will be fun and attractive.
Hi Todd,
is not my intent of course to develop fast boat with J Class and 12Metres since is not the purpose.
The main purpose is instead to have very elegant “open design” boats on the water as to catch the eyes of observers and skippers and future skippers.
Is not also the purpose to fall in the selection and measurements of water lines being often laborious and source of conflicts and in contradiction with the Open Design concept. Of course a Rule shall exist !
I nevertheless recognize that, after having put my “nose in”, the J Class will suffer from displacement volume compared to the 12Metres when all scaled to 127cm length (50").
In order to compensate this lack of volume I will study and develop a deeper keel as done already for bigger models.
With that action I will try to gain volume and righting moment as done already with other scales.
It is not excluded to increase additionally the volume by fairing the garboard curvatures and width of keel.
Fast sailing model boats obey to other Aerodynamic/Hydrodynamic concepts like the ESTEREL 123, AC120 where the sail ratio/displacement is one of the criteria, other then fin blade/bulb and righting moments.
My conclusion is that the series of models, subject of this tread, are closely developed from original plans as such that they will be first compatibles with a recognized and existing VM Rule, and second to allow J Class and 12Meters racing separately with boats in the range of 50" length. To my knowledge “open design” J Class and 12metres of 50" length do not exist yet.
Canterbury is 48" long and “one design”, EC12 is 58" long and “one design”, US12 is 46" long ‘one design’, Newport 12Meter of 72" ‘one design’, J Class 1/16 with 85"-95" length
Modelers are free to implement also original deck layouts instead of using a “flat” deck and participate to Construction Excellence Award.
Cheers
ClaudioD
The ENDEAVOUR II Drawing revision is made :
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Next preparing drawing for Deck layout and Shadow templates ready for printing to scale 1 : 1
ClaudioD
Endeavour II Sail Plan & Righting Moment :
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Displacement and righting moments are almost the same with Ranger 1937.
Accepting a heel angle of 45° the Rig A can go up to 10kt of wind speed. (nautical knots)
I’m referring always to nautical knots and not to terrestrial mph as seen often when describing Rig Options vs Wind speed.
1 knot (kt) = 1.15 miles per hour (mph)
ClaudioD
Man that looks good.
I thought I should mention that Marblehead Class rules will allow you to make a taller rig if you desire.
You can use any rig, with the maximum height of the headboard of the mainsail being 85" above deck. This generally equates to an 80" Mainsail Luff.
Note that means the mast can be taller than 85" above deck to accomodate the masthead crane and etc… The rules are that the Headboard of the Mainsail has to be 85" above deck.
Clearly the righting moment of these traditional boats will limit your ability to use a super-tall rig… but that doesn’t mean you can’t. In peticular, the Madcap can benefit from a much taller rig over that which is proposed in the plans. Lighter air… use a Taller rig
Swing-Rigs are prohibited on Traditional and High-Flyer Marblehead class models for obvious reasons.
Hi Breakwater,
no doubt about the Mast height since foreseen by the Rules.
From my point of view the taller rig is not very efficient since at the extreme eight the available surface is just a small percentage of the total and the power contribution is irrelevant. This is the case of Class M where it is much more profitable to use a lower rig for the same surface and consequently profiting also of the lower CE position.
Having said , modelers are free to choose the rig as they like and according to Rules.
At the moment I’m exploring the various options and my approach tend to be rather conservative since based upon the real design plans.
Outside the technical aspect, I would consider also the aesthetic point.
At glance here below a comparative sketch of two rigs with the same sail area.
The Marblehead type rig is probably producing the less efficient setup of the two !
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All comments accepted !
Cheers
ClaudioD
Claudio.
You are 100% right on all accounts. And, really, a super-tall rig looks stupid on a Traditional hull. And that’s the bottom line.
Im only conveying the idea that you could if you wanted to… All the way up to an 80" luff.
There is real-world benefit though to using a taller rig. For instance a Madcap fitted with a tall rig is a light-air spanker.
a 68" mainsail luff is probably the Maximum I’d ever use on a Madcap. And effectively when it’s real light air.
I like the smaller rig… as it will do 2 things.
- it will help with the righting of the ship… lower coe
2 the smaller rig. looks like it belongs on the boat. plain and simple
i am realy looking forward to those endeavour II pdf…
My J did not come out like i drew it. but wow… did i learn alot about design and why they put all those control points in
Hi Breakwater,
from my experience and extensive use of an anemometer on the shore, I do not recall having noted variations of wind force from 1.5mt to 2.0mt height although a curve on the subject will tend to prove that may exist, unless is just a graphic extrapolation !
Practically below 2mt height, the winds are unpredictables and the use of a tall arm bring more unwanted facts then good ones.
Once, some one used a 2.5mt pole and every 10cm starting from 50cm from ground put radio cassette ribbons of about 30cm long and observed how the ribbons floated. As far I remember, where all moving in the same manner !
Of course, as usual, the factor “fashion” is always playing a big role ! .
I was once racing against a better Class M then mine, a Margo, equipped with Rig A of 216cm tall and mine Studio3 with a rig B (same surface) but 25cm shorter Mast. Wind force variable from 0 to 4knots, who was the first crossing the line ? Was the Studio3 with about 5mt advance. Of course under such conditions is not only the wind that count …but Studio3 was also 300g heavier !
Some years ago we where testing Class M against AC120. wind force changing that day from 3 to 5 Knots and some small gusts and cloudy
Class M : real developed sail surface 7200cm² - Mast height 216cm and 4.35kg
AC120 : real developed sail surface 7800cm² - Mast height 165cm and 4.55kg
The AC120 was always in the front exhibiting the best sailing capability and fast accelerations in all directions.
The heeling was almost the same with some prevalence with AC120. Of course the M fin blade was 8cm deeper then 42cm of the AC120.
Here in attachment a graphic about wind force variation vs height, I ignore how it was done, but for me is like a theoretical extrapolation !!! and my Studio3 the yellow one that was also closing better !
Cheers
Claudio
PS:
Today busy with various deck layouts found here and there for the Endeavour II and finish up with the printable PDF shadows.
Not easy to collect data about Endeavour Deck layout, but at the end I managed to get something sufficiently detailed.
Several pictures available on the web by digitizing : Endeavour 1937.
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ClaudioD
PS: I miss the side windows on the central roof !!!
ENDEAVOUR II .zip Files
ClaudioD
PS: New updated file Endeavour 1270 - rev1 added
ooooooo thank you… I think this gets started in june . when i get the money together… Thank you
guys anybody else building the beautiful J?
Yup.
But Claudio.
You sir are on a roll. Keep it coming. The Marblehead class in the U.S.A. Gives you their most sincere thanks.
Arghhhh… I can’t open zip files on my phone!!! Can anyone recommend an android app to do this?
Other than that, I’m positive she’ll be absolutely stunning - such beautiful graceful lines…
Regards,
Row
all i can say is wow… thank you again…
can i ask a few question before i start to build…
#1 what ballast weight do you think we should shoot for… 3 kg of lead in the keel. be enough to keep the 72 inch mast upright? or the smaller mast would be correct?
#2 the winch that is going to be used… . figure a 40 kg drum winch would be enough?
and this is just for me… and i play to work this out… just wondering if you had any idea. using the twinn jibs would make for an interesting model
start time june 1. now all i need is supplies…
this sure looks better than the one i designed…
40 kg ??
On a drum winch that’d be way overkill - 800 sq inches isn’t that big really, I’d of thought somewhere between 9 & 15 kg would be plenty. My only experience of the Marblehead class is from the late 80’s & early 90’s - back then the rolls royce winch was the Whirlwind Olympic which had about 10 kg/cm.
Cheers,
Row
Thanks a lot to all of you and I’m pleased to see that this type of work is appreciated. This is my compensation for the many hours spent behind the screen. Is not a sacrifice at all is just my pleasure to do it.
I have updated my Endeavour II files posted above by introducing the Endeavour 1270 rev1 of main plan since I introduced the ballast template.
The actual ballast weight considered is 3.0kg.
The total displacement is 4649g.
The 3.0kg ballast is compatible if the total construction will be contained within the 1649g, But the righting moment will still too low to cope with medium wind speed.
Actually the calculated righting moment was referred to a deeper keel configuration not yet formalized with precise drawing.
The plans for that configuration are not yet made, but I can anticipate that the displacement volume will of course increase and therefore more margin will be available for the construction. It may be possible that also the ballast may be increased a little.
All drawings made up to now are based on the original plans without any modifications to the hull. Only the Sail Plans are modified to be compatible with the Marblehead Rules.
For Cougar:
the nominal Mast height of Endeavour II 1270 is about 58". The use of taller mast will pull up the CE and therefore the righting moment will be drop. Personally I will not recommend to use 72" Mast, such a solution will work only with very very low wind speed. Let’s wait the deep keel configuration.
About the servo, I think that what Row said is correct, you may use also an Eurgle or similar or eventually the HS785 although slow and bit too heavy.
Are you referring to gun shoots ? Be careful, the specific weight is almost half the lead weight and would require the double of the volume.
If inserted in the actual hull, the CG will be going up and the righting moment will be drastically reduced.
The ballast I consider are with lead specific weight of 10.5kg.
I will concentrate now on Deeper Keel design drawings starting with the Endeavour and see what happen !
For Row :
have you managed to open .zip file ?
Cheers
Claudio.
Hi Claudio,
Thank you for GREAT work!
If I could wish I need Endeavour with draft 149% of oryginal yacht. And real scale sails.
Best regards
Grzegrz