It's Friday so I might as well get the pot stirred for the weekend.
I have a busy day today so at the risk of sounding "terse" I'll keep my answers short and you can assume each comment is preceeded by "with all due respect". And yes, there are always exceptions.
In short, with all due respect, I think you are wrong on just about everything you said. Forget about today's fat assed boats. Let's go back to the 50's and 60's with skinny, deep boats and many with full keels and odd CCA and IOR hull
shapes. Everything is done by the designer
to increase stability. Increased stability was ALWAYS a target of design. That's why both the IOR and CCA had elements in thejm to penalize stability. No one wants to sail heeled over. Of course you balance the innefficiency of heeling against the horse power provided by the rig at that heel angle and many times the hp wins the battle. Horse power is good and more hp at a lower heel angle is REALLY good. But given the choice you sail the boat as upright as possible while using the max hp available.
I do not think a slack bilged boat needs some heel angle to sail at optimal speed. I would use some heel in very light air so the sails
fall into an efficfient shape. But that's the only reason.
( for an in depth
look at the effect of overhangs on boat speed read the chapter in my book where I use VPP's to evaluate he effect of heel angle on sailing length and bat speed). There's another good argument for another day.
Excesive weather helm
is a design flaw regardless of the type of boat, full keel
or fin keel
. Yes, you can overcome the drag by pushing the boat hard but you would be far better of with helm
angles bellow 4 degrees. Drag is not good. If you have to "trim out" the helm at the cost of speed this indicates poor design. There are many. many full kele boats with little weather
helm and many with none. Have you ever sailed a 12 meter or a 6 meter? They have full keels and slack garboards but they also have dead neutral helms in moderate air. For the boats of the era we are discussing weather helm comes from having the keel too far forward ( center of pressure) or the rig too far aft ( center of pressure). Baggy old sails
and a poorly tuned mast
can also add helm.
My philosophy is to always try for a near neutral helm. It's always possible to dig up some weather helm if you want it and sometimes you do want it, but it's not always poosible to get rid of excessive weather helm wihout compromising sail trim. I hate poorly balanced boats.
I'll start piling up the sandbags now.