Glad you like it
Well hello there, Jim!
Actually there has been a pretty consistent thread on this and related topics for the last few years-with many of the key points repeated in several different threads...But no matter.
I'm glad you are enjoying this, but I fear you may be a bit confused (and this is one which I spent a LOT of time explaining previously) on the bend vs. rake discussion.
Also I have no idea what you are referring to when you said "topping lifts with vangs change sail shape because of mast bend"??? Please let me know on that one!
Mast bend will change sail shape, and the vang will also-in a different way. The topping lift is used on boats without 2-way vangs to open the leech in light air (mostly cruisers).
Please look back for a very detailed post I gave on this topic, but I will briefly run through it for you here:
RAKE, which is the "at rest" fore and aft location of the masthead, changes the center of effort relative to the Center of gravity in the keel, and hence the "feel" of the "helm". Moving the masthead back will move the CE BEHIND the CG, and INCREASE weather helm. The by product is higher pointing, or better upwind performance at the expense of downwind speed. In light air (especially for racing) you want aft rake to help your upwind performance. In heavy air, ideally you would want less rake to reduce what may have become excessive weather helm. Certainly if you going to be adjusting rake, you would want LESS in heavy air-not more. Cruising boats rarely adjust the rake once they find a good spot-but MANY cruising boats DO bend and unbend their masts-it is easier and more practical. RAKE is changed by using BOTH the headstay and backstay to move the top of the rig. Just changing one of these will not really affect the rake. In the 70's, many race boats used hydraulics to both bend the mast AND change the rake when sailing. This was ultimately found to be 'too effective" and the rules now allow only one (headstay or backstay) to be adjusted while racing. The idea is to allow mast bending, but not raking. Rake may always be adjusted before or between races.
One you have the RAKE set with given lengths for the HS and BS, most boats that have adjusters will use a BS adjuster, which will do 2 primary things: Tighten (or loosen) the headstay, and bend/unbend the mast. Obviously they are done in concert with each other. Add BS tension, and the HS gets tighter (which flattens the jib), and bends the mast back (which flattens the main). Get the idea? Big wind requires flatter sails, and adding BS tension does this for both sails. When the breeze lightens up, easing the BS will "power up" the main by "unbending" the mast, and "power" up the Jib by alllowing the HS to sag off more-which is very fast in light air. The mechanics of why the main gets flatter when the mast is BENT (not raked) aft is discussed in more detial in old posts-The reason you are bending and not raking in this scenario is that the headstay is not changing its' fixed length-only the BS-Got it?
Great outhaul question!! I love this one. When the boat is consistently heeled more than about 15 degrees, you need the flattest sails you can get-that means "maxing" out the outhaul to get the lower 1/3 of the sail as flat as possible. When the wind gets light and the boat feels "starved" for power, I will usually ease the outhaul 2-3", or put differently, go for a max. of about 3" of "depth" or amount of sail that settles to leeward just above the boom.The exact amount varies from sail to sail, of course. Be carfeul of the "old salts" who say "Bag it out"-a "fat" sail WILL accelerate from a stop better than a flat one, but it has a built-in top speed limit because of the drag due the "fatness" of the "wing" section or profile.
When sailing downwind, these same guys may ease the outhaul 8-10" sometimes-thinking it is fast, but remember that downwind is the least efficient point of sail and the only time that the only driving force you have is projected area (as opposed the lift), so if you ease the outhaul a lot you reduce the distance from the tack to the clew, and hence projected area. In fact, easing the outhaul too much is the same as REEFING!!
The cuningham/downhaul has been discussed. Only use it IF: the sail is ALL the way up, and the draft is visibly aft of the 50% mark (fore and aft). If the sail is well stretched out, and if you have excessive wrinkles in heavier air, you can use it gently to remoive the wrinkles-but this is NOT the prime function of a cunningham or halyard, for that matter-they are used for keeping the max. draft in the best location. Luff wrinkles in light air are fine-again as long as the draft is forward of the middle of the sail.
Really kept it short, huh?
:eek: :eek: