INTRODUCTION
The Loos rod rigging tension gauge is designed to provide an accurate measurement of the tension in rod rigging used in sailing yachts and other such applications. It is particularly useful for accurate and repeatable tuning of sailboats standing rigging.
[For the Soverel 33, the Model RT-10 is appropriate. The Lower and Upper shrouds have a 0.198"rod diam., and the intermediate shrouds have a 0.172" rod daim.]
The Model RT-10 covers a tension range of approximately 5% to 25% of the breaking strength of the rod and is designed and tested to provide an accuracy of plus or minus 5% at mid range.
[The breaking strengths of 0.198 and 0.172 rod is 6,300 lbs. and 4,700 lbs. respectively.]
SAFETY AND PERFORMANCE
Safety The failure of a fitting or shroud or stay could damage your boat, buckle the mast or even cause personal injury. To avoid such failure of rod or fittings from either fatigue or shock loading, it is important to set up your standing rigging with proper tension. Too little tension in the shrouds will permit the leeward shrouds to go slack, only to fetch up with a jolt when the boat rolls or pitches. A less common problem is excessive tension. This can cause permanent stretch to the rods and , possibly damage the mast.
Performance The actual set of sails under load is determined by the cut of the sail and the shape of the structure which supports the sail. Rigging tension plays an important part in determining the set of the sails.
When a boat has been tuned for peak performance, measured rod tension should be recorded. The stainless steel used to make the standing rigging can stretch a little bit over time under high loading. Thus, marring turnbuckles, etc. cannot guarantee that subsequent adjustments will provide the desired tension. Only by gauging is it possible to repeat the initial tuning or improve it.
If the shrouds are not set up with enough tension, the leeward shrouds will go slack when the boat is sailing to windward.
How Much Tension?
Many skippers use insufficient tension because of tear of "breaking something." It should be noted the on Americas Cup contenders, where good tension instrumentation is available, the standing rigging is set as tight as is structurally feasible.
Upper and Lower Shroud Tension There is a simple criterion for shroud tension. The initial rigging tension should be high enough that the leeward shrouds do not go slack when sailing close-hauled in a reasonably brisk breeze. The proper value for you boat can be found by a few trial runs under sail. Once the correct tension is know, the gauge can be used to maintain this value.
Benefits of Correct Rigging Tension
Contrary to popular thought, a slack rig is more punishing on a hull than a properly adjusted, tight rig. Insufficient tension will reduce the loads transmitted to the hull. Slack rigging will punish the spar and rigging needlessly by allowing excessive movement, chafe and shock loading. Modern fiberglass hull should not be damaged by a properly adjusted, tight rig.
RT-10 Calibration SCALE LBS.
0.172% of
Breaking
StrengthLBS.
0.198% of
Breaking
Strength
Orders and information for this Loos Tension Gauge should be sent to:
Loos & Co. Inc.
Cableware Division
901 Industrial Blvd. Naples, FL 34104Tel:(941) 643-LOOS, 1-800-321-LOOS (5667)
Fax: (941) 643-4558, E-mail:Loos Tension Gauge: www.loosnaples.com/cable/RT.htm