Development
and Trialling of Mylar Sails
Report #2 - Frank Bethwaite
As a youth Shane Guanaria sailed with his father Ian
and routinely finished top ten in major Tasar regattas. (Ian
was for many years
Chief measurer for the Tasar World Council.) Shane then sailed
Lasers and represented Australia in the Laser
World Youth Championship in 1999. He works with Ian MacDiarmid,
and made the
new mylar
sails. These
were finished a few days ago. I now have a hull but have not
yet rigged the spars.
During the week Shane telephoned and asked if I would agree to
his trialing the new sails in the Sunday races at a weekend Tasar
regatta. I agreed.
Venue: Bethwaite Design regatta
at Speers Point, Lake MacQuarie.
Fleet: 25 Tasars, 12 29ers,
6 B-14s
Saturday program: Several races
completed in severe frontal conditions.
Sunday program: Five back-to-back
races.
Course: St-W1-G1-L1-W2-L2 Fin,
St/Fin line 200m upwind of L
Wind: The cold post-frontal
southerly air was about 1 to 2 degrees colder than the 24 degree
water temperature of the lake. The wind
pattern was of constant, small, sometimes severe, “bubbles“ of
unsteadiness which occurred at random within a much larger pattern
of half kilometre patches of stronger and lighter air.
Waves: Up
to 1 ft.
Crew: Shane G and Jeanette Russo,
Shane’s fiancee. 145kg
total. This was Jeanette’s third sail and first regatta.
Protocol: Shane
started with the Tasar fleet, sailed to clear air without adversely
affecting any competitor, did not slow any competitor,
conceded at marks, and did not cross the finish line. Shane and
Jeanette returned ashore after the fourth race.
Measurements: I timed
parts of Races 1, 3 and 4 from shore, and all of R2 from a rescue
boat.
“Exp” denotes the experimental boat, “T” the
first Tasar to round the mark.
The sequence of each line is - Mark; time difference for leg,
Wind/velocity
a + time difference indicates Exp boat got to the mark first
| |
Time of rounding |
Diff |
| Mark |
Exp |
T |
(secs) |
| |
|
|
|
| Race 1 |
|
|
|
| W1 |
11:13:44 |
11:12:51 |
-53 |
| G1 |
|
|
|
| L1 |
11:17:42 |
11:16:22 |
-80 |
| |
|
|
|
| Race 2 |
|
|
|
| St |
11:40:30 |
11:40:30 |
|
| W1 |
11:50:24 |
11:50:40 |
16 |
| G1 |
11:55:02 |
11:55:10 |
8 |
| L1 |
11:58:33 |
11:58:40 |
7 |
| W2 |
12:07:15 |
12:07:40 |
25 |
| L2 |
12:13:28 |
12:13:44 |
16 |
| Finish |
|
|
25 |
| |
| Race 3 |
|
|
|
| L1 |
12:44:16 |
12:43:20 |
-56 |
| W2 |
12:51:40 |
12:50:44 |
-56 |
| L2 |
12:58:09 |
12:57:31 |
-38 |
| |
|
|
|
| Race 4 |
|
|
|
| G1 |
13:27:21 |
13:26:24 |
-57 |
| L1 |
13:32:24 |
13:31:28 |
-56 |
| W2 |
13:38:35 |
13:38:01 |
-34 |
| L2 |
13:44:50 |
13:44:22 |
-28 |
Summary
To windward X was about 4% faster on 3 of 4 legs timed,
no diff on 4th.
Downwind X was slower in early races; faster in later
races.
Crosswind Average difference about zero. X sometimes trapped,
sometimes unable to pass, due protocol.
Observation
Leeches of X rig noticeably more mobile than any adjacent
T rig.
Frank Bethwaite
Posted 2005/03/09
|
