Stable figures
I'd like to comment on Dave Gerr's interesting and informative article on sailboat stability ("Ultimate Stability," Part 2, October).

Dave's sidebar discussion of "STIX: The Stability Index" suggests that this (relatively new) standard may not be too useful as an analytical method for determining a vessel's stability characteristics. As the U.S. participant on the international work group of designers and naval architects responsible for developing this particular ISO standard, I'd like to provide some background on its development and shed some light on why I believe it will grow to have considerable value to both the design community and the boat owner.

As Dave's article illustrates, the accurate stability assessment of any sailboat is a complex process. Numerous design characteristics influence the ability of any boat to safely resist or recover from capsize, ranging from downflooding openings to the shape of its righting-moment curve. In all, the ISO work group found that seven different calculated factors encompassed all significant stability concerns and, taken together, could establish a single stability index value (STIX) that allows meaningful stability comparisons between various designs.

The minimum STIX value for each category was created and validated from a study of a large number of existing sailboats, ranging in size and type, that had experienced capsize events, with and without successful recovery. Good correlation was eventually obtained between theory and practice, and the final STIX standard, I think, encompasses all critical stability factors in an analytical method that is based on established principles of naval architecture, sound methodology, and correlates well with real-world experience for real boats. No other single stability-assessment method, to my knowledge, is as comprehensive as STIX.

I should also point out that while the STIX method is by its very nature a complex calculation, the standard does have an annex that allows for a much simpler method. While understanding the actual STIX value that would result using the more rigorous calculation, the optional method can quickly establish suitability for a desired Category for certain designs (for instance, large, heavy boats with conservative rigs would likely attain a Category A STIX value using either method of calculation).

Lastly, I’d like to comment on the Capsize Screen method mentioned in another sidebar. This was proposed in the 1985 USYRU and SNAME Joint Committee Report on Safety from Capsizing (prompted by the 1979 Fastnet disaster). As Dave correctly states, and I heartily reinforce, by itself the capsize screen evaluation method has virtually no value in the assessment of a yacht's stability. It's really addressing a concern that lightweight designs with a wide beam are suspect regarding their susceptibility to capsize, justifying further stability evaluation. One of the seven STIX factors addresses this very issue.

Technical tools for towing
I enjoyed reading your articles about trailersailing (August) and found the tow-vehicle tutorial very interesting and well written. I was, however, disappointed that the formula to calculate the actual towing capability was never stated. An excellent resource for this is Kenneth Lenger's Towing Weight Demonstrator Spreadsheet at:

http://www.klenger.net/arctic-fox/weight/towing-weight-demonstrator.xls

Screaming about screaming
Re: "Screaming Along" (Setting Sail, August), I would no more ascribe such antisocial behavior exclusively to men than I would to members of a particular race or religion. Doing so is repugnant not only for its inherent sexism and bigotry, but for its glaring inaccuracy. Anyone who hasn't observed women, as well as men, engaged in poor behavior on the water needs to get out a little more.

More practice, less screaming
My wife and I gave up racing for the same reason you did—screamers. The screaming at the crew made the experience too stressful and no fun. My wife began to think she'd rather be working than racing.

I think screamers scream for three reasons:

1. They are unsure of their own abilities
2. They can't find or keep good crew
3. They don't practice

Screamers want the crew's total dedication, but they won't dedicate themselves to doing what it takes to make the boat sail well. They must commit the time required to build and train a crew that will work well together. Thinking you'll be successful with a pick-up crew, regardless of experience, is a formula for defeat…and screaming.

While I'm much happier cruising, I'll admit that I miss the excitement and camaraderie of racing. But I certainly don't miss the screaming.

Balancing act
I'd like to share this picture of our 1988 Catalina 30, Paradise, which my wife, Barbara, and I sail on Long Island Sound. On this weekend there was no wind, and we put in at Eatons Neck Coast Guard Station where there is a little-known private gunkhole. There is skinny water in spots, and we found just such a spot. Unfortunately, it was also an extreme low tide, which emptied most of the water in the gunkhole. The Coast Guard took this picture one hour before dead low when we were already high and dry for 300 feet around the boat. We stood still, held our breath, and said our prayers, not daring to move about the boat as we were perfectly balanced. Three hours later when the tide came in, we drifted off unassisted without damage.

Lighting confusion
In the May issue, you presented many safety-inspired comments on sailing at night. There was an error in the sidebar "What the Colregs Say." Mr. Springer states that Rule 30 (anchor lighting) reads, "All vessels under 164 feet must show one white light..." This is a common fallacy, as is the belief that a single anchor light must be at the peak of a sailboat's mast.

The rules on anchor lighting generally consider larger vessels first, then provide optional configurations that smaller boats "may" adopt as needed. A smaller vessel may always opt for the lighting required of a larger vessel, including Rule 30—a configuration of two all-round white lamps with the forward one higher than the aft one. The minimum visible range required for vessels less then 12 meters long is 2 miles. Confusion regarding where a single lamp should be placed is natural since few of us study the rules in detail.

Using a fixed light at the top of the mast is convenient—flick a switch and you're done. But how well does such a light, elevated to 40 or 50 feet, illuminate your vessel to others approaching at a close range? In some cases, the lamp intensity dwindles inside of 30 yards.

Adding deck illumination is also a great way to be more visible at anchor. Rule 30 requires this of large vessels. For small boats this could be as simple as a fluorescent stick lamp tucked under the main boom.

As one who has had close encounters with fishing vessels, having some options ready when anchored goes a long way toward sleep-time safety.

Efficiency Issues
I read with interest "Which Fridge?," by Nigel Calder (January), on refrigeration systems and efficiencies. Although the discussion focused on efficiencies, no numbers were actually stated. This is consistent with what my wife and I found last year when equipping our 44-foot Van de Stadt Madeira. We could not find an quipment vendor who would actually quote on efficiency.

Instead, I received advice on anticipated energy consumption, based on the box I was proposing to build—that is, on the insulation value of the box itself, rather than the refrigeration system. I found that there was virtually no difference in the anticipated energy consumption from one vendor to another, based on my box design.

I think that any discussion of the efficiencies of different refrigeration-system designs is pure speculation and wasting one's breath—until manufacturers are willing to show some numbers without considering the impact of the insulation or efficiency of that box. Refrigeration-system efficiencies should be quoted on the basis of KW (or Ahr) of electricity required to move a certain amount of heat (Btu) from inside the box to the ultimate heat sink-atmosphere or cooling water. Anything else is advertising noise designed to confuse.