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 better information.

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 consistent measurements.

Rake: 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.
Outhaul: Clam foot design should be opened downwind and reaching by easing the outhaul and cunningham. Keep closed upwind unless abnormally choppy.
Strut: 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.

Keyed in by

Ali Meller
ameller@mcimail.com