SJS, to answer your question first, left to its own devices under bare poles with the helm amidships, the bow of most boats will pay off to leeward and the boat accellerate downwind and in enough wind
will broach. By putting the boat helm down, the boat goes through a series of small cycles as the bow of the boat will actually start to pay off and make a little way, then the helm turns the boat back up to windward again, and the force of the wind
stops the boat, and the next cycle begins. It is easy to experiment
with this even on a calm day. I usually use this technique to keep the boat in one place while I flake the sails
when I am single-handing.
What you say is quite reasonable and I apologize if I seemed to be overly critical of your posts or seemingly over agressive in my writing style. I also wish you well. I really do want to be helpful rather than convert people to the "world according to Jeff".
In the spirit of extending an olive branch and while I don't know if this will be helpful to you, if you don't mind, I will try steer you towards good sources of more up to date information and also provide a kind of summary of the material upon which I have been basing my opinions. Much of my most current
information comes from research papers presented at the Society of Naval Architects and Marine
Engineers (SNAME) Sailing Yacht Symposiums but I think I can explain the general trend in what is coming out of the research and aim you at sources as I do so.
Prior to the research and the improved engineering that began roughly 20 years ago, when you talked about light weight boats these boats were made light by reducing ballast and scantlings but without compensating in any other way. So a light weight boat was often structurally inferior and generally had a comparatively high vertical centers of gravity. Early lighter weight boats generally relied on high form stability and crew weight on the deck
to stand up to their sailplans. Because that was pretty much the only light weight boats that really existed in those days, it was a safe conclusion as late as the early 1980's that light weight boats really were not suitable for offshore use.
There are a lot of very excellent books written (or revised) in the early 1980's that explain that issue very well. Probably the best of those was C.A. Marchaj's "Seaworthiness-The Forgotten Factor" which explained the physics behind seaworthiness. His explanations of the physics of seaworthiness are still extremely accurate in much the same way that Coles storm strategies are still very accurate. What is not accurate is their condemnation of lighter weight boats, which was in great part based on the typical light weight boats of that time (mostly IOR era race
boats and cruisers based on the IOR rule) and not on the light weight designs that evolved after that period. They cannot be faulted for looking at the boats that existed and not predicting the changes that were to occur.
Here is what has changed. In the 1970's and into the early 1980's the laminates and resins being used in fiberglass
boats changed pretty dramatically. Longer fiber fabrics and better fabric
handling techniques became the norm. Less brittle and fatigue prone resins also became the norm as boat builders tried solve the resin problems associated with blistering.
Also at this time, racing
began to look at the issues of flexure which was seen as slowing the boat. It was concluded that you could not effectively reduce flexure in a fiberglass boat without internal framing. This was a major departure from earlier f.g. boats desgn principles. Early fiberglass boats were purposely designed without internal framing in order to create more interior
volume. The belief at time was that framing was not necessary because satifactory stiffness could be achieved by making the hulls thicker. This greater thickness was generally achieved by the use of higher proportions of non-directional fabrics (mostly mat). We now know that non-directional fabrics reduce impact resistance and increase brittleness and the likelihood of fatigue. (There are several excellent monographs on this subject that were produced in the mid-1980's and most recently an insurance
industry study of insurance
claims on older fiberglass vs newer boats in which included very interesting destructive testing of actual panels
from older fiberglass boats. The insurance industry study was available on line. There is also a recent Naval Academy study that is very good as well.)
So in the late 1970's/ early 1980's designers began to reduce weight by adding framing in the form of glassed in tranverse and longitudinal members and later through the use of pans or grids, and by using better laminates which all permitted lighter weight without compromising strength.
At the same time, several other things happened. Research coming out of the Fastnet Disaster began to focus attention on the evils of high vertical centers of gravity and moments of inertia, extreme form stability and trying to cram too much displacement on a short waterline. (Much of this is explained in Marchaj but some of this comes from later reseach where full sized boats are instrumented and data collected)
Also the racing rule
changed so that stability was no longer over penalized as it was in earlier versions of the IOR.
1983's Australia's America's Cup victory introduced the world to wing keels but more universally it brought a lot of attention to the posibility of lowering the vertical center of gravity by shifting ballast lower in the form of a bulb at the bottom of the keel. Suddenly race boats and cruisers alike began to sprout bulbs in one form or another. Most of the so-called wing keels that are on the market, really function as end plates and bulbs more than as true winglets.
If there has been a real revolution in yacht design, I would say it is in the IMS type form which is characterized by extremely low vertical centers of gravity, moderate to low form stability, fine bow sections to minimize slamming, and careful weight and buoyancy distribution to maximize dampening and minimize pitch
and roll accelleration and angles.
As to sources for this, there was wonderful research done at Shiphydrodynamics Department of Delft University, Ship Science- School
of Engineering Sciences and the Wolfson Unit at University of Southampton
. and the Australian Maritime College, that looked at the factors that impact motion at sea, stability, wave action,etc. Some of these research result papers can be found on line. (If you can find them, two really good source papers are "An Experimental Investigation of Slamming on Ocean Racing Yachts" [mainly within the preamble] from the Ship Science- School
of Engineering Sciences at University of Southampton
and "The re-righting of sailing yachts in waves- a comparison of different hull forms" from the Australian Maritime College. Both can steer you to other earlier studies that were quite useful to me as well.)
Hopefully that should round out your reading list.