JANUARY 20, 2026 THE DEFINITIION OF "LIGHT AND VARIABLE WIND"

 

JANUARY 20, 2026

THE DEFINITION OF “LIGHT AND VARIABLE WIND”

Predictions for wind were dismal, and the limp flags confirmed the forecast.  It looked so weak that some boats opted to not come out.  As we left the harbor around 2pm there was a breeze developing by the wharf and we had a break in the predominant heavy cloud cover.  As the clock ticked down, there was a mild 5-6 knot breeze.  The wind was coming from 240 degrees, so we decided to set an offset mark about a quarter mile roughly upwind and called for a course of: S/F>offset mark>Mile>S/F.  We blew the five-minute horn which seemed to be a signal for the wind gods to go back to sleep.  We had 9 boats out for the drift-fest. At the start, boats were drifting across the start line in a 3-4 knot breeze.  Fortunately, as we sailed further out, the wind seemed to increase with close to 9 knots as we approached Mile.   As we rounded  Mile, the wind died and the finish at S/F seemed out of reach as most boats bobbed with no forward movement.

Despite the curse of no wind, 3 boats actually finished the complete course.  I offered the option of taking the finish time at Mile so everyone could stop bobbing.  The first boat to round Mile was Flexi Flyer, then Aboriginal.  Though Main Squeeze sailed and finished the long course, their track froze so I could not report a finish time for them.  The afternoon sail was a definition of “Light and Variable wind”.

 

Jennifer Kinsman photo of the drift-fest

                                           

The track for this afternoon can be reviewed at:

https://www.regattahero.com/mapviewer/?organisation=scyc&passcode=233793&regatta=Tues%20Fleet%20B&race=20.1.2026%2015:00:00&language=en&defaultspeed=5&loop=no

PHRF ADJUSTED RESULTS : SHORT COURSE: FINISH AT MILE COURSE DIST .965NM

PLACE                BOAT                               PHRF                  ET                         CORRECTED

1            FLEXI FLYER                                96                        19:05                  17:32

2            ABORIGINAL                                33                        19:12                  18:40

3            PERFECT 36                                  144                      25:06                  22:47

4            AVATAR                                         132                      25:03                  22:56

4            ROSIE                                            162                      25:33                  22:56 (TIE)

6            AQUAVIT                                       72                       24:10                  23:01

7            SAILING PAIR A DICE                180                      27:15                  24:21

8            SAGITTARIUS                                120                   26:25                  24:29

LONG COURSE FINISHERS:  COURSE LENGTH 1.930NM

1            ABORIGINAL                                33                         46:17                  45:13

2            FLEXI FLYER                                96                         52:26                  49:21

 

Next Tuesday will be the last Tuesday of the month and we are back on track to have our end of month BARBECUE.  Bring your best grilling food to cook and share.  Pray for fair winds and good weather!

ZOOP SCOOP BY PAUL TARA

PRISM SENTENCES

In geometry, a prism is a 3 dimensional solid shape, with flat, parallel, polygonal ends connected by parallel sides.  A simple example would be the edges of a straight 2 x 4, with parallel ends.  In yacht design, aside from length, beam, and draft, the prismatic coefficient, or Cp, may be the one of the most descriptive statistics when it comes to hull shape. It basically represents how tapered the ends are, as a ratio, relative to the hull’s largest underwater cross section. A vessel  with no change in shape from bow to stern, like a barge (or an un-tapered 2 x 4), has a Cp of 1, or close to it.  The more tapered the shape is at the ends, the lower the number.  

 

Like wetted surface, Cp is difficult to calculate unless you have lines and a CAD program. For many designs it’s proprietary. But, just roughly, sailboats with low numbers tend to have finer ends, more rocker, less wetted surface, and lower top speeds.  Those with higher numbers have fuller ends, less rocker, more wetted surface, and higher top speeds. For example, the Cp of  a SC50 is around .56, while those of similar sized IOR designs could be down in the low .50’s. That’s because Cp is a hull-speed indicator, and lowering it by pinching the ends produced lower ratings. Then, there’s the tricky part, depending on its shape, a yacht’s Cp can change dramatically as it heels (scow bow anyone?).  

 

Modern performance designs, like sprit-polers and, now, foilers, have very high Cp’s, edging towards .60.  The further apart a designer can push the crests of a hull’s bow and stern waves, the faster her “wave train” travels. (Think of a super tanker, where the crest of the bow wave is often ahead of the hull itself.) For a given length, the higher the Cp, the longer the wavelength, resulting in a higher hull-speed, The higher the hull speed, the sooner a boat can achieve her planing or foiling speed. Once that threshold is crossed, theoretical speed limits go out the window..  

 

If you want to view examples of prismatic extremes, just pay a visit to the Club’s Junior Yard, where Optimists and El Toros are stored side by side. Although both designs have hard chines, Optimists are ‘bricks’ with flat bottoms, and little rocker, (high Cp) —they are slugs in light air.  El Toros are tapered, with more rocker and more dead-rise (lower Cp) — they’re faster, until conditions get ‘sporty’ when they become difficult to control. And then, of course, locally there’s the ultimate light-air speedster, the Jester Dinghy, which may have the world record lowest Cp.

 

By the way, the Club is selling a few of its El Toros.  They are ‘well-seasoned’, but you might want to take a look.

Thank you Paul!

I hope to see you sailing next Tuesday and at the BBQ at the club.

Barry Keeler

Sailing Pair A Dice