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Fine Tuning Your J/70 Rig and Batten Tension

A big part of success on the race course is having the correct rig tune and batten tension for the conditions. Quantum’s Travis Odenbach explains his approach to fine-tuning his rig and batten tension using clues on the water.

Always be testing - Teams sail around before the start keeping an eye on their settings. Photo by Lara Dallman-Weiss.

In a recent article, we shared tips on how to put your boat together for a successful launch, including setting up the rig tune. When practicing before an event, we focus on so many different things: crew weight placement, crew work, sails, and how the boat speed is compared to our tuning partners. On-the-water batten tension and rig tune are two steps that are often overlooked during pre-regatta practice. Here’s my approach and what I look for and how to manage both on the water.

BATTEN TENSION

Putting battens into the sails and getting them just right for the conditions can be a bit of a headache. When I started sailing J/70 boats, I noticed a lot of teams were tightening battens to remove wrinkles in the batten pocket. The downside is that I found you can take it too far. You don’t want the batten to be so stiff that it doesn’t pop through onto the next tack. My rule of thumb on the dock is to tension the batten until the Rocket retainer loop on the leech end of the sail is snug and can’t come loose. From the leech of the sail, I like to hold the batten and sail up to make sure the batten can tack through the sail with ease. If it does not, you are probably too tight; if you see wrinkles, you may be too loose. This is the most efficient way to check tension on land.

Now it’s time to go sailing and really take a look at each batten while on the water. This should be one of the first things you look at when you hit the sail. Let’s say it is a beautiful day to sail at 10 to 12 knots. Take a look up and make sure your batten pocket doesn’t have any puckers in it, and, while tacking or jibing, make sure the batten can pop through. You can also check tension by sail shape. Recognizing this is a learned skill that only comes with practice. However, in 10 to 12 knots, your sail shape should be smooth and not too deep or full at the battens. You can also tell if you have overtightened battens by looking at the luff, especially in the full-length battens. If the battens are too tight, the luff of the sail will look like it is being pushed toward the mast. The most obvious sign that your battens are too tight is when you’re gybing the main and your battens do not tack through the sail. This can be one of the most annoying things to happen while on the race course and not something you want to fix mid-race.

RIG TUNE

When thinking about rig tension, we often focus on what to prepare while on land. Get your rig to base, check side to side, and make sure you have the correct amount of rake. But what should you do when you get on the water for your first day of practice? The first step is to go through the rig tune matrix. This will let you know exactly what number of turns it will take to get to each rig tune step. But the truth of the matter is that a tuning guide is a guide and not something set in stone. Each rig may have a different bend allowance or each set of spreaders may be slightly different. Practice is the best way to find out what works for your specific boat and sailing style, not just for sailing in different conditions and keeping notes, but also for sailing with another boat. 

After your rig is tuned to the base settings and your battens are properly set, it’s time to take a look at the shrouds. To start, I recommend sailing upwind and looking leeward to make sure there is subtle play in the leeward upper. You want to check this just when the shrouds are starting to move. You don’t want them flopping all over the place, just showing a slight bounce. Usually this gives me a good idea of how much headstay tension I have and tells me that my rig is not falling off at the top. Once you set the rig to where you think it should be, take a look up the mast and ensure everything is in line. Now look up the mast from the gooseneck and make sure there is no leeward sag at the spreaders and that the top of the mast is not hooking to windward or falling to leeward. If your mast is straight at the top and bottom but sagging to leeward in the middle, adjust your lowers a half or full turn and recheck. The same thing goes for the middle of the mast if it is poking to windward. This is when you can start to move away from the guide. Write down how many turns you have made so you can easily get back to base if needed. 

Testing your Lowers

Once you’re confident with your set-up, test it. Look at your mainsail as you start sailing. If your lowers are too loose, the mast will have more bend, resulting in a flatter sail. The best way to test this is to put on a lot of backstay in a puff. If your lowers are too loose, your mainsail will invert too quickly and you will see a large crease starting from your spreaders to the clew on the mainsail. Tighten your lowers until you’re able to use the appropriate amount of backstay without getting a crease too quickly. With the deck step mast on the J/70, it’s sometimes hard to avoid turning your mainsail inside out, so I prefer to set up the rig in heavy air so that I can put on a lot of backstay, and, at the very end, I can start to see the crease in the mainsail. I will usually ease slightly from there on the backstay control line.  

Testing your Uppers

If your uppers are too loose, the first tell-tale sign will be a very bouncy headstay. If you have a loose headstay, the slot between the jib and the main will close quickly. You will most likely see your main break up every time you ease or want to depower the boat. 

Getting your batten tension and rig tune set on the water is one of the most important reasons to get a good practice in before a regatta and ensure that you’re using your sails to their full potential. It’s also helpful to grab a partner at the regatta and practice with them. This allows for debriefs at the end of the day to figure out who sailed better or what you learned from the day of sailing. Ask your tuning partner to meet every morning before the first start and tune up with them.  

Getting proper rig tune and tension is a learned art, and the better you become at it and find your preferences, the more you’ll get out of your sails and races.

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