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.
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