Dockside Tuning

[JonnyBoats]

Having watched Biron's video on Rig Tuning, I have a question:

In the video Biron takes up on all the turnbuckles at the dock with the boat on an even keel, thus turning the turnbuckles under load.

In his book "Offshore Sailing, 200 Essential Passagemaking Tips", Bill Seifert states:

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

Comments?

...just that I'd rather have the visual clarity of a video shot on the level at the dock than either the action shots on a sailing boat or the carefully heeled-at-the-dock shots. It's easier to understand the techniques being taught if I'm not distracted by altered perspectives/angles and an instructor fighting gravity.

[Brion Toss]

Hello,
If you tighten by the normal method (tightening both threads at once), you can put too much torque on the barrel, even to the point of damaging it. This is less likely to happen with clean threads and stout barrels, but it can be a problem. Unless, of course, you use the tightening technique shown in that video, which results in half the load on the barrel, as well as the tuner.
Fair leads,
Brion Toss

[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

[Brion Toss]

Hi again,
The two-part method is certainly easier on the barrel, but won't help the threads. A little lubrication (dry) makes a lot of difference, as I'm sure you have found. As for damaging the threads while tightening, this could conceivably happen, sans lubrication. I know that tightening all-stainless turnbuckles under heavy friction can lead to spin-welding.
Fair leads,
Brion Toss