The Loos tension gauges take the guesswork out of cable or rod tension adjustment. They are especially designed for accurate, repeatable tuning of a sailboat's standing rigging.
Contrary to popular thought, a slack rig is more punishing on a hull than a properly adjusted, tight rig. Insufficient tension will not reduce the loads transmitted in the hull. Slack rigging will punish the spar and rigging needlessly by allowing excessive movement, chafe and shock loading. Modern fiberglass hulls should not be damaged by a properly adjusted, tight rig.