USING A TUNING GRID
- Tuning Grids are only a guide. To race effectively you still need to understand the reasons for the settings stipulated in tuning guides.
- Tuning guides assume you are using the correct mast and sails and the mast and boat controls are calibrated and configured exactly the same as the boat used to determine the settings in the first place.
- Different mast/sail configurations can work but you will need to make minor adjustments away from the grid settings. To do this you would need to understand what the various settings do, experiment and develop your own grid.
What is a tuning grid
Tuning grids are a great tool to quickly set up a boat without having to think or know too much. For example when conditions change in the middle of a race and you need to spend as little time as possible with your head in the boat reconfiguring for best speed the grids give you a set of quick go-to settings.
Tuning grids, normally provided by the various sail makers, are a check list of how the sail maker and the best sailors using those sails, believe the rig should be set up to get optimum performance in the various conditions. They have generally been determined after many hours of tuning and racing. The 5O5 Class is renowned for how, even the best, share their experience and knowledge. So the guides are a good starting point for the less experienced sailor without the time or expertise to learn the best setup themselves.
HOWEVER. More often than not they don’t appear to work. We set up our boat as recommended but are still not competitive. Focusing on the tuning grids can actually make us slower. Why Is this?
I am using the grid. Why am still not fast?
Tuning grids tell us how much rake, rig tension, vang, mast ram, etc and even jib sheeting and centre board positions to set for different wind strengths. However optimum boat speed is about optimum sail shape and balance. Setting up to a grid isn’t the objective. Obtaining the correct sail shape and balance is the objective. The grid is merely a cheat sheet that, if followed should give you the correct sail shape. See How do I change Gears?.
For the grid to be accurate and work for you as a guide, EVERY other setting on the boat needs to be identical to the set up on the boat that developed the grid. That includes the type and position of the mast step in the boat, the size and position of the mast gate the point where the side stays and forestay are attached, the position of the ram, where the spreader bracket is, where the forestay and hounds are attached on the mast, and even the position, shape and size of the foils.
All of these things (except foils) affect the way a mast bends and therefore directly affect sail shape. Different sails are also generally designed differently and require a mast to bend differently. See commentary on mast Pre-bend in Where Do I Start
If you don’t have exactly the same mast, set up in exactly the same way and positioned in exactly the same place in the boat then care should be exercised when using a tuning grid. Those settings are a good starting point but you may still not be set up optimally. You still need to focus on sail shape and performance and make minor adjustments to the rig settings to get the best sail performance.
Its important to understand and recognise the sail shape you need for the different conditions and how that sail shape needs to change when conditions change.
Its all very well to change the rig set up as per the Tuning Grid but if that doesn’t change the sail shape correctly the boat will still not perform.
Make sure you understand why and how the various rig controls at your disposal change sail shape and try recognise what the sails should look like in the different conditions..
Raking a mast does not de-power a boat. Flatter sails de-power a boat.
If you ‘copy’ your set up from a faster boat (or use the tuning grids) make sure EVERYTHING on your boat is configured the same. If not you will need to use slightly different settings than the grid suggests.
One way of overcoming any potential differences in your particular set up is to make sure your mast bends to suit the Luff round in the mainsail you are using.