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Tuning your rig with Rig Sense

Tuning your rig with Rig Sense

Spinlock's Rig Sense tension gauges help you get the most out of your rig, and repeat the settings every time. The below article helps you to use the Spinlock Rig Sense to tune your rig:

Rig Tension - Tuning Guide
Most people know what their rig settings should be, but don’t know the forces they are putting through the rig and the hull. We will try and help you get a better idea of what forces you are putting through the rig using the Spinlock Rig-Sense.

We know the fundamental job of standing rigging it to hold the rig up, however we can affect the performance, safety and longevity of the rig and boat by having the rig over or under tensioned.

To start your rig tuning, you need to get a good starting point. Download the settings from your class website, sailmaker or rig manufacturer. This will show you how to step the mast, adjust the mast so it is straight, with the right amount of pre-bend and rake (depending on the type of your rig).

Download our App

We recommend using the Spinlock Rig-Sense App to import, log and share your rig settings. This can be downloaded for free via the Play Store or Apple App store.

Once you have the mast up and set to BASE settings, you can attach your Spinlock Rig-Sense. The numbers at the bottom will be in kilogrammes…but what does this mean?
Wire cable measures its strength by breaking strain, approximate numbers can be found in the table below:

Most dinghy and keelboats with fractional rigging set their cap shrouds to 20% of the breaking strain of the wire.
For example, if you are using 3mm 1x19 wire, (breaking strain = 790kg) your BASE shroud setting should be approximately 158kg at 20%. 
This might seem a small amount compared to the wire breaking strain, however you must consider the strength of the other fittings attaching the wire to the hull and the mast. Over tightening the shrouds will cause a lot of compression through the mast, potentially creating permanent damage to the hull (do not exceed 25%).
An under tensioned rig could lead to a mast failure. If you are unsure about the right tension, contact the boat, rig or sail manufacture for more advice. 
When measuring the tension of your rig, we recommend the following:

  • Position the boat head to wind, on flat ground with your mainsail down or up (as long as it’s the same every time).
  • Always attach the Rig-Sense at the same place, at least a metre away from any terminals. We recommend eye level with the KG scale, then mark with a permanent marker or electrical tape.
  • Once attached to the rig, push on the base of the gauge, so the pointer points at 0kg and release.
  • If adjustments need to be made, this can be done with the Rig-Sense still attached to the rig.
  • Repeat the other side of the rig to confirm settings. If possible, measure the tension on your forestay. This will highlight any issues with the rig setup.

Mark your wire or rope for easily repeatable settings:

Once you are happy with the tension of your rig, head out sailing and see how the boat feels. If possible, sail alongside a similar boat to yours and look at your speed and height compared to your partner. Here are some common problems relating to incorrect rig tuning:
•  Sail too full with sail controls on (Kicker, Outhaul Cunningham) – Try more pre-bend
•  Not pointing upwind very well – Try more aft rake
•  Slack leeward cap shroud – Tighten caps shrouds equally on both sides
•  Mast has an ‘S’ curve – Adjust lowers and intermediates
•  Excessive slag on the forestay – Tighten forestay/backstay on a masthead rig, tighten cap shrouds on a fractional.
•  Poor performance downwind – Try raking the mast forward
•  Once you are happy with your performance, log the settings in your Rig-Sense App for easy access.

TIP: Use Bicycle inner tubes to protect your pins:

*Settings will vary depending on rig type and material.
**Remember not to leave your Rig-Sense gauge on the rig for long periods of time and in direct sunlight. 


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