Keel-Stepping a 12

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Keel-Stepping a 12

Postby breakwater » Wed Apr 25, 2012 7:30 pm

Are there any rules against keel-stepping an EC-12?

I'm relitively new to the class. and love how these 12s sail, but man they would benefit from a keel step.
Both in sailing performance, & pre-race stepping procedures. :twisted:
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Re: Keel-Stepping a 12

Postby s vernon » Wed Apr 25, 2012 8:24 pm

http://ec12.net/images/Bldg_Ideas/Lower ... eneck4.jpg
http://ec12.net/images/Bldg_Ideas/Main_ ... nboom3.jpg

I do not want to say one of a kind, but rare anyway. Sail number 18. YRN 1354
Round mast,
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Re: Keel-Stepping a 12

Postby breakwater » Wed Apr 25, 2012 8:47 pm

Pretty sweet.

I don't know the players in this class too well quite yet, And I don't know that paticular boat, but I'd venture to say it's an "aged" boat.. With '94 Bob's Boat yard sails.
I assume that means there are no rules against Keel-stepping.

What if I were to order a brand-new boat today.. and said to the builder.. "I want that boat keel-stepped"
Would I be legit?
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Re: Keel-Stepping a 12

Postby s vernon » Wed Apr 25, 2012 9:33 pm

It is legal. I figured you were willing to build it yourself. You might have to pay a bit extra if you can even find someone good who is willing to take on the job. I do not think there is much interest in this subject, as the current boat and rig seem to work very nicely.

I think conventional and best wisdom for new people is to not try to reinvent the racing EC-12.
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Re: Keel-Stepping a 12

Postby breakwater » Wed Apr 25, 2012 9:57 pm

I understand entirely..
In actuality I'm not having a boat built, and don't plan on it. Meerly using those questions as examples.
I am campaigning an older Hickman, and will do so for a while, but curiosity strikes in the meantime... And, it seems if any of my model yachts were to benefit the most from a keel-stepped rig, it would be the 12, which is sailed without.

If I were to ever put one of these together, I would ask a builder to do it for me...
Personally I spend my mediocre building skills in developmental classes.
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Re: Keel-Stepping a 12

Postby Jon Luscomb » Thu Apr 26, 2012 10:38 am

What are the perfomance advantages to a keel stepped mast as opposed to a deck stepped mast?
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Re: Keel-Stepping a 12

Postby breakwater » Thu Apr 26, 2012 6:00 pm

The primary performance advantage to a keel step would be transmission of energy from the mast directly to the keel.
(In comparison to a true-deck-step whereas that energy terminates at the shrouds & deck step)

It would technically increase the lever arm of the mast, Therefore increasing the effort of the sailplan transmits to the keel.
The more effort you can put to the keel, the more you can to oppose it with the opposing force of Lateral resistance. And, the more you oppose it, the less heeling effect, and faster boat.

With the increased lever arms, you can then play with the hull shape because it's now more stable. (hull beam and etc, but this conversation is irrelevant to the 12)

Case & point is the M-Class.
Over the years the fulcrum arm on both sails & keels have gone to super-high aspect ratios.
All modern M's are keel-stepped, and most are shroudless rigs, with stiff masts.


Now, There are 3 ways to step a mast.
1. Keel-Stepping.
2. Deck-Stepping, with a compression strut (Which is how my Hickman is) Which accomplishes nearly the same thing
3. True Deck-Stepping. Seen on only really turd boats or day-sailers.

If My boat is Deck-steped with a compression strut, why not build it with a true keel-step?
On my boat, I could use another roughly 6" of mast length before I bottom out on the lead!




The primary practical reason for keel stepping is to keep the rig upright.
It doesn't happen all the time, but how many times have people been dis-masted during a regatta on this forum because someone clipped your rig?
Hit the shrouds, down goes the rig, and it's floating on the side of your boat. You're now a lame duck till someone gets the Kayak off the roof.
With a Keel-Step, someone clips you, and your rig is still upright.


The primary tuning reason for keel stepping is plug & play.
Slide the mast in the proper step-hole and it stands straight up in the wind. Commence laughing at the others who fumble their mast while they try and attach a shroud or two :roll:
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Re: Keel-Stepping a 12

Postby hedderick » Thu Apr 26, 2012 10:01 pm

The boat shown earlier in this thread is Gerhard Kelter's #18. I sail against this boat and it is fast. Is it the deck stepped mast, the boat, or the skipper? Probably yes, yes, yes.
Gerhard's boat is built similar to Bob Stern's Viper and Venom, with three mast hole tubes supported internally.

I own and sail a Bob Sterne Venom 36/600. On a Bob Sterne Venom (36/600) the mast is held vertical in the mast tube. As mentioned previously in this thread, the mast is held vertical at the base, giving it more overall strength. Tuning the boat is different. With little jib stay tension, the mast can be bent to the desired curve with the backstay. Then jib forestay tension is adjusted with the bowsie on the jib forestay. Overall with this Bob Sterne design, the mast bend adjustment and forestay sag can be more independently adjusted. On a EC12, with a deck stepped mast, to get a lot of mast bend, there must be quite a bit of jib forestay tension (and backstay tension).

A keel stepped mast in an EC12 could potentially offer more flexibility in tuning. Additionally, because of the strength added by the mast being supported at the base, the mast would tend to be more rigid in a given set up. So when a puff hits, one might expect to see less mast deformation and sail shape change. This potentially could be an advantage, because we always seem to be sailing in puffs.

These comments are just food for thought. The Ec12 is already deceptively complicated. A keel stepped mast would be a great experiment, but also a great challenge. Even if the keel stepped boat were faster, it would probably be difficult to say it was the keel stepped mast that really made it faster. There are so many things that make these beauties go....
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Re: Keel-Stepping a 12

Postby breakwater » Thu Apr 26, 2012 10:45 pm

Funny you should mention Sterne,
I also have 2 Vipers, a Kisutch and a Venom US1M.

While the kisutch is deck-stepped, the others are not (Keel). That came along with the development in developmental classes.



Well, you're right.
Even if the keel-step on a 12 made for a faster boat, it would be difficult to say if it was only the keel-step that made it faster.
In my short time in this class I'm picking up the nuances between station widths, keel widths and etc. All within a "one-design" class.
There does seem to be lots of variables in the class... so it would be tough to isolate 1 change to a net result.



It was just an idea, just a thought.
To me, all boats should be keel-steped regardless.
But, If I were to pick 1 boat, 1 design that absolutley had to have a keel-step, I would chose the 12.
(Or J-Class for that matter - for the same thought process)

With all that mass I would think it be best to send the driving force (mast) right down into the boats arteries and get it moving.
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