AN ULDB DAY
Predictions for the afternoon were for 1-10 knot winds. The flags confirmed that there was at least
some breeze. As we left the harbor at 2 o’clock
there was a consistent light breeze of about 7-10 knots. The question, as always was “what does the
future hold?”. With the wind coming from
roughly 230 degrees, we got ambitious and called for W5: S/F>Schuyler>S/F. I had posted in the blog and announced on the
radio that it was a single fleet race and that the horn would blow at 5 minutes
to the 3:00 start. I also instructed to
register as Fleet B in Regatta Hero. All but one boat followed the
instructions.
All of “B fleet” got off to a clean start and tacked their
way to Schuyler. After rounding
Schuyler, all boats sailed down-wind to the finish. It was a challenging down wind run with all
boats experiencing very light patches of wind.
Homer once told me that if you knew exactly what conditions there will
be for a race, you can design a boat specifically for those conditions that
will win. This afternoon presented conditions
that was definitely a ULDB (Ultra
Light Dispacement Boat) day.
Photo by Jennifer Kinsman
PHRF ADJUSTED RESULTS:
FLEET B (ALL BOATS) COURSE W5 DISTANCE 2.4NM
PLACE BOAT PHRF ET CORRECTED TIME
1 RIO 141 49:06 43:28
2 PERFECT 36 144 49:25 43:39
3 ROSIE 162 50:14 43:45
4 YELLOW
BELLY 141 49:33 43:54
5 ZOOP 144 50:46 45:00
6 AVATAR 132 50:40 45:23
7 SAILING
PAIR A DICE 180 53:23 46:10
8 SIMPATICO 165 53:33 46:56
9 AQUAVIT 72 53:25 50:32
10 WINDLUST 66 1:00:25 57:46
NEXT TUESDAY WE WILL HAVE ANOTHER SINGLE FLEET RACE.
PLEASE BE CERTAIN TO ENTER FLEET B IN REGATTA HERO AND BE CERTAIN YOUR PHRF IS
CORRECT. ALSO MONITOR THE VHF CHANNEL 69
FOR ANY PERTINENT ANNOUNCEMENTS. A SINGLE
HORN WILL BE SOUNDED AT 2:55 FOR A 3PM START.
THE ZOOP
SCOOP BY PAUL TARA
HORSES & COURSES
It
has been hinted by some that one of the reasons Zoop sails in the B fleet is
that we are “afraid of getting beat”. (Betcha I got your attention with that!)
While we have enjoyed success in the B fleet, that’s not the reason.
There are actually two, Perfect 36 (a Catalina 36 Mk I), and Avatar (an
Olson 911). Zoop rates 144, P-36 the same, and Avatar rates 132 (she owes
us 12 sec/mile). Depending on conditions, and crew performance, it’s
anybody’s game. Two weeks ago and again this week P-36 sailed a very nice
race and beat us quite handily, while this week we finished overlapped with
Avatar.
Let’s
take a look. P-36 displaces 13,500 lbs. (44.4% ballast), on a 30.25’
waterline, with a SA/Disp ratio of 15.71 and a Disp/L ratio of 217.73.
Zoop displaces 13,450 lbs. (40.5% ballast) on a 28.25’ waterline, with a
SA/Disp ratio of 16.35 and a Disp/L ratio of 266.1. Avatar displaces
7,500 lbs. on a 27’ waterline, with a SA/Disp ratio of 20.45 and a Disp/L ratio
of 205.7. P-36 is longer, lighter for her length, but has a little less
power for her weight. Zoop is shorter, heavier for her length and has a
little more power for her weight, while Avatar is shorter, but only about half
as heavy, and has a much more power for her weight.
So,
why doesn’t Avatar just speed away? The answer is in the kind of races
we’re sailing — predominantly moderate air windward leewards. Upwind, if
there’s breeze, the two bigger boats with their longer waterlines, have an
advantage. Downwind, the advantage should shift to the much lighter Avatar.
But, as they say, the devil is in the details. One of those is
wetted surface, which is a key factor in light/moderate air. Unfortunately, it
is also very difficult to calculate absent a set of lines or a CAD design
program. Suffice it to say, for a given displacement, the geometric shape
with the least wetted surface is a sphere, ie round boats have less wetted
surface. Wide flat boats have more. Compared to the other two, Zoop is
actually quite round.
.jpeg)
Which
brings up the next question. Why isn’t P-36 faster upwind? She’s longer, and
has more ballast. But Zoop carries hers lower. She draws about 6” more,
has a significant bilge (stubby) above the lead, and her keel is a ‘camouflaged
bulb’, having a much thicker section at the bottom. Many light displacement
boats have no bilge, because their canoe bodies have been made as shallow as
possible to shed displacement. But, hey, there’s no free lunch. This adds
wetted surface, while at the same time placing the ballast higher, where it’s
less effective. Unless, of course you have a true fin/bulb where all the
ballast is at the bottom.
But,
every design is a compromise. I’m sorry, I can't resist — “What kelp?”
Thank
you Paul.
Barry Keeler
Sailing Pair A Dice
