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Old Dec 15, 2012, 11:21 AM
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United States, MA, Wenham
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Originally Posted by The Tug View Post
On the jib pivot drum to the front there is a thumb screw that adjust the jib boom end height,i have owned a Scalpel sinse 1999 and won two nationals but not figured this out yet lol,One year Janus was there and did the adjustment for me because of the language barrier i never understood a damm thing he was trying to explain i just sent it down a counted the turns relative to each rig and marked it on the jib,to this day i still don't have a clue what it's for.
Post 774 previous page third pic shows this thumb nut clearly.
If it adjusts your jib boom end height, isn't this essentially your jib topping lift?



If you move the end of the boom up & down it will add some twist or remove twist from the top of your jib-sail.
Most jib booms have a pivot about 4" aft of the front of the jib-boom. When forestay tension is applied, it forces the aft part of the jib boom down toward the deck because of the fulcrum applied to this pivot. The jib topping lift coutner-acts this force pulling the aft end of the boom up in order to put shape in the sail.....
Put just enough to match the twist in your main.

Obviously the Skalpel has a radial jib fitting, which does not require a jib topping lift because there is no fulcrum applied to the connection point. But, it still requires a jib-slot.



Another thing the radial jib fitting does is allow the full sail-plan to be fully exposed to the wind on the downwind leg, similar to a swing-rig but without swinging. On other rigs, the roughly 4" on the forward secion of the jib boom is shadowed behind the mainsail because of the pivot point.


The Radial jib fitting theoretically is faster than a conventional rig, because, well, conventional rigs point better upwind with a full-jib and the sailplan not offset just a slight degree because of the swinging mast.
Downwind they are theoretically equal as both rigs expose the full sail-plan.

By comparison a swing rig is superior to a club-footed (not radial jib fitting) traditional rig because the 4" of the jib's sailplan is shadowed behind the mainsail.


Science!
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Old Dec 15, 2012, 11:53 AM
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Then in 'turbo' mode we Skalpel's move the jib aft on the boom. This projects the jib even more downwind, and gives the boat more helm in light air upwind. Sweet stuff...
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Old Dec 15, 2012, 11:53 AM
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Actually, there are two thumb screws on the jib pivot fitting. If you look at the picture below, I believe you are talking about thumb screw #1. It looks like the primary function of that screw is to rotate the fitting. I would guess that you would want to start with that fitting perfectly square with the forestay to maintain an even jib luff tension and freer movement. Thumb screw #2 would pivot just the jib boom clew up and down, solely adjusting the jib leech tension.
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Old Dec 15, 2012, 11:55 AM
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The adjustment of the angle of the jib pivot controls how much the vang changes as the sail goes in or out. One way to adjust the angle is to sheet all the way out, adjust the vang for the desired twist, then sheet in. Now adjust the pivot angle to set your twist while sheeted in. Now you have set your twist for both sheeting positions. since the forestay angle changes as the rigs change that adjustment will need to be changed for each rig.
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Old Dec 15, 2012, 12:09 PM
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Quote:
Originally Posted by Houdini13 View Post
Then in 'turbo' mode we Skalpel's move the jib aft on the boom. This projects the jib even more downwind, and gives the boat more helm in light air upwind. Sweet stuff...
Now that is really sweet!
Couple that concept with the butterfly system, and that's why the Skalpel is wicked.

Walicki Skalpel 3733 Servo and butterfly demo (0 min 17 sec)



I also really, really like the flexible rudder concept..
The aft end of the rudder is flexible, so when the rudder turns it acts more like a fish-tail than a hard surface.... Smart stuff.
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Old Dec 17, 2012, 10:32 AM
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Quote:
Originally Posted by slotracer577 View Post
The adjustment of the angle of the jib pivot controls how much the vang changes as the sail goes in or out. One way to adjust the angle is to sheet all the way out, adjust the vang for the desired twist, then sheet in. Now adjust the pivot angle to set your twist while sheeted in. Now you have set your twist for both sheeting positions. since the forestay angle changes as the rigs change that adjustment will need to be changed for each rig.
That sounds to be the most plausable answer,thumb screw #2 is a vang and found on both booms.
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Old Dec 19, 2012, 08:59 AM
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Facebook Link

Guys
I have just joined Facebook, anyone who wishes to link up with me please use the following:

http://www.facebook.com/taylormadeyachts

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Old Dec 28, 2012, 06:51 PM
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Phew..
Some time during the holidays means a refurbished "Archer"
What's everyone else building? get after it!



Dick L.
How's your build coming?
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Old Dec 29, 2012, 05:16 AM
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Joined Jun 2005
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Hi breakwater,
I was wondering where you been as it went quite on here

I'm doing some mod's to my Dreadnought for the coming season.
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Old Dec 29, 2012, 02:04 PM
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Originally Posted by breakwater View Post
Dick L.
How's your build coming?
Boy, I'm glad the wife doesn't read these as I would be in serious trouble. Purchased the foam-core board before Christmas, and managed to print a set of templates for the GOTH (applied to the foam board, but not yet cut out), and also for a very skinny one based on the design of my Formula48 multihull cross-sections. (Basically an upside down hull similar to those used in the A-Class, the C-Class and now the AC Cup multihulls) This one will be purely experimental, and may wind up as a glass over, solid foam hull. The other will probably be a hybrid of strip building (balsa or cedar) with maybe some 1/64 thick wood veneer.

In any case, with the holidays a lot has come to a stand-still and I would like to continue once the holidays are behind me. Perhaps I can sandwich in a build along with the wooden pedal car projects. My tow-truck project (wood) has expanded to a wooden 1932 "Hi-Boy" design car to go with the truck. Ahhhh - grandkids ! If I am successful, the wife will never know what it is I am working on. Good to keep her in suspense and completely confused!

Regarding the skinny one - I was unable to find anything in the "M" Rules that prohibit any "standoff side shroud adjustments similar to what some of the big boats were/have used coming off the sides of the hull gunwales amidships. Since they don't extend forward or aft of the hull, I am under the impression they could extend beyond the sides (but still wondering what happens if a competitor's boat scrapes along the entire side in a port/starboard issue?) Anyone care to comment on legality? (not practicality since this "IS" an experiment?

Cheers - and Happy New Year to all.
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Old Dec 29, 2012, 03:57 PM
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Quote:
Originally Posted by Dick L. View Post
...Regarding the skinny one - I was unable to find anything in the "M" Rules that prohibit any "standoff side shroud adjustments similar to what some of the big boats were/have used coming off the sides of the hull gunwales amidships. Since they don't extend forward or aft of the hull, I am under the impression they could extend beyond the sides (but still wondering what happens if a competitor's boat scrapes along the entire side in a port/starboard issue?) Anyone care to comment on legality? (not practicality since this "IS" an experiment?...


5.2.9 No part of a rig shall be forward or aft of the hull when the main and jib clews
are held on the centerline plane of the hull.

5.4.5 Except as in 5.2.9 any part of a rig may be outboard of the hull.

and

1.1.2 Anything not specifically restricted or prohibited is PERMITTED.


I don't see anything in the rules that prohibit them either. However, I do share your concern about contact with another boat. Both the damage to your boat as well as the damage to the other boat.

I am not sure that the view is worth the climb.
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Old Dec 29, 2012, 04:28 PM
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Building a Brad Gibson Jive here
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Old Dec 29, 2012, 06:26 PM
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Quote:
Originally Posted by Dick L. View Post
Boy, I'm glad the wife doesn't read these as I would be in serious trouble. Purchased the foam-core board before Christmas, and managed to print a set of templates for the GOTH (applied to the foam board, but not yet cut out), and also for a very skinny one based on the design of my Formula48 multihull cross-sections. (Basically an upside down hull similar to those used in the A-Class, the C-Class and now the AC Cup multihulls) This one will be purely experimental, and may wind up as a glass over, solid foam hull. The other will probably be a hybrid of strip building (balsa or cedar) with maybe some 1/64 thick wood veneer.

In any case, with the holidays a lot has come to a stand-still and I would like to continue once the holidays are behind me. Perhaps I can sandwich in a build along with the wooden pedal car projects. My tow-truck project (wood) has expanded to a wooden 1932 "Hi-Boy" design car to go with the truck. Ahhhh - grandkids ! If I am successful, the wife will never know what it is I am working on. Good to keep her in suspense and completely confused!

Regarding the skinny one - I was unable to find anything in the "M" Rules that prohibit any "standoff side shroud adjustments similar to what some of the big boats were/have used coming off the sides of the hull gunwales amidships. Since they don't extend forward or aft of the hull, I am under the impression they could extend beyond the sides (but still wondering what happens if a competitor's boat scrapes along the entire side in a port/starboard issue?) Anyone care to comment on legality? (not practicality since this "IS" an experiment?

Cheers - and Happy New Year to all.

YES!
Awesome to hear you are turning the wheels.
What's the best way forward? Turn the wheels, don't spin them!
Small progress forward is still a step in the right direction.



In regards to the standoff shrouds, Well, really there shouldn't be any contact between boats on the race course. Does that happen? No, but I won't be concerned about a feature of your boat slowing you down because of contact.
Contact and wrapping-up can occour regardless..... How many times have rigs been tangled at the head? Plenty. Shrouds inter-twined on the same tack? Plenty.
If another boat comes through and breaks your offset shrouds, well, you get redress.

The first rule of racing is you avoid contact. No matter what.





Now, with that said.. An offset shroud rack seems like it would slow you down as it might drag in the water when heeled.
But, again this is your design, you know what will make your boat go, and what will make it not.

Even if your design doesn't work the first time, there's always another try. This is the M-Class, you can do whatever you want.

How many versions of the Broom were there?
Broom 1, Broom 2, Broom3, Broom 4, Broom 5!
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Old Dec 29, 2012, 06:31 PM
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Originally Posted by NZL756 View Post
Building a Brad Gibson Jive here
Boogie!
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Old Dec 29, 2012, 07:09 PM
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United States, DE, Wilmington
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The first rule of racing is you avoid contact. No matter what.

Actually, that is not correct. It is the 14th rule and it only says "if reasonably possible" and "shall not be penalized under this rule unless there is contact that causes damage or injury."

14 AVOIDING CONTACT

A boat shall avoid contact with another boat if reasonably possible. However, a right-of-way boat or one entitled to room or mark-room

(a) need not act to avoid contact until it is clear that the other boat is not keeping clear or giving room or mark-room, and

(b) shall not be penalized under this rule unless there is contact that causes damage or injury.
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