Ullman Sails East Epsilon Tuning Sheet
The following is from an Ullman Sails / Proctor Epsilon Tuning Guide,
from the early 1980's (I believe). I only have one page, so it is
probably incomplete. I believe these numbers are from Steve Benjamin.
My recollection is that with both the Sobstad and the Ullman sails, Benj
used two mains, a full top and a flat top. From what I can recall, the
Lindsay 505 Benj raced in the 1981 Worlds had the shrouds ending at
the rail, fastened to traveler cars on a short track. He used turnbuckles
to adjust shroud length, and could move the cars for-and-aft about 8 inches
or so. He discusses this and the alternative of adjustable spreaders at
the end. Steve runs Banks Sails on Long Island, and may be able to provide
The following measurements are taken will full rig tension pulled on and
the mast [as] straight as possible. To straighten the mast the strut may
need to be adjusted slightly, and this should definitely be done to obtain
- measured with main halyard locked, through tiller port, and to the
intersection of the transom and the bottom. Should be 25' 8" plus or minus one inch"
for extreme conditions. Try raking further for heavy air.
- Rig Tension
- medium air headstay tension should be 330 pounds. Shroud tension
should be 500-600 pounds. Increase shroud tension in heavy air to 700
pounds to decrease jib sag and bend mast.
- Spreader Length
- 17" measured from center of wire to inboard end at mast. aft deflection"
measured from aft side of mast to straight line between shrouds should be
4". adjust aft to 5" for very light or heavy air.
- Step Position
- 10'0" from aft side of mast at step to transom."
- Centerboard pin location
- 8'8" from transom (jib tack at bow)."
- Centerboard Position
- front edge perpendicular to keel line.
- Top Batten Tension
- just firm for light air and flat water. In harder to hold a curve in
moderate chop and heavier air.
- Clam foot design should be opened downwind and reaching by easing the
outhaul and cunningham. Keep closed upwind unless abnormally choppy.
- Used to control lower mast bend and mainsail fullness. Adjust strut down
to firm the upper leech of the main and add fullness. Ease the strut or pull
it up with the prebender to induce more bend low, flatten the mainsail and
twist the leech. IMPORTANT: keep prebender cleated in trimmed position
when running to prevent the mast from inverting.
- Adustable Spreaders
- are an option which allows adjustment of the angle and length of the spreader.
A simple alternative to adjustable shroud travelers for adjustment of upper
mast bend. Spreaders should be adjusted forward as the wind increases to
restrict mastbend, until the boat is overpowered. At this point the spreaders
should be eased aft again to depower.
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