[Brian Duff]

I am familiar with the technique of achieving full tension with less effort by turning both the barrel and upper terminal half turn, then spinning the upper terminal back to where it should be before grabbing another turn on the barrel, but I was under the impression that this was only to make tensioning easier, and possible on larger boats.

I have been tuning rigs for years by holding the top terminal stationary while spinning the barrel until my tension is as I know it needs to be , and this works on up to around 35' boats without any apparent issues.

"Never tension a turnbuckle that is under load. If it is not convenient to take the boat for a sail to adjust shrouds on the leeward side, heel the vessel at the dock by running a spinnaker halyard to a fixed object and tension it to induce at least a 5-degree angle of heel"

Am I to understand that a turnbuckle cannot handle being loaded by the threads with a wrench at the dock, but it can handle much higher loads while sailing ?

Brion made things a bit more clear by indicating that the torque on the barrel can cause damage, but he must mean damage to the 'H' structure of the barrel maybe cracking or twisting it, not the threads, unless the threads are corroded ... right ?

Hoping to learn a better way,
Brian