Wave Tuning

Article by Eric Heim (published in the last Snipe Bulletin)

You get to the boat park early. Coffee in hand. It has been a tough week, but it is time to go Snipe Racing! When you arrive at the boat, you pull the cover off. Hello old friend! It looks just like you left it after sailing last time. You think back to last month. Were we fast? How was our point compared to the winners? Better check the rig tune…

Out comes the tape measure, tension gauge, your sailmakers tuning grid, and your personal notes (you have those right?!?). A quick glance at the forecast on your smartphone reveals 8-10 knots, but with some waves leftover from the front that came through last night. Hmmm, last time you sailed it was similar wind speeds, but flat water. Point was good, but we were a little slow…

How should the boat be tuned differently for sea conditions? Equally important, why?

Article by Eric Heim (published in the last Snipe Bulletin)

You get to the boat park early. Coffee in hand. It has been a tough week, but it is time to go Snipe Racing! When you arrive at the boat, you pull the cover off. Hello old friend! It looks just like you left it after sailing last time. You think back to last month. Were we fast? How was our point compared to the winners? Better check the rig tune…

Out comes the tape measure, tension gauge, your sailmakers tuning grid, and your personal notes (you have those right?!?). A quick glance at the forecast on your smartphone reveals 8-10 knots, but with some waves leftover from the front that came through last night. Hmmm, last time you sailed it was similar wind speeds, but flat water. Point was good, but we were a little slow…

How should the boat be tuned differently for sea conditions? Equally important, why?

 

cdfa54053805c4a7f07a2686eb2f2fc9 LImagine for a moment that you are sailing in 8-10 and flat water. Look up and take a mental picture. Skipper and crew are on the rail, but hiking in the puffs. Boom is on centerline with the top telltale stalling 50% of the time. Jib trimmed to about 16″ off centerline.

Now go through the same process in waves. Skipper and crew are moving more actively as the boat loads and unloads going over the crests and through the troughs. Mainsheet is eased a bit with the top telltale flying 85% of the time. Jib is trimmed out to 17.5″ off centerline.

Why have we changed the way we sail to accommodate the added sea state?

The skipper and crew need to move weight around since the apparent wind is changing drastically from the crest to the trough. More rudder is required to keep the boat tracking well in the groove. The team will get more tired in waves because of the extra energy. The sails are eased because we are no longer working our hardest to point super high, the boat needs to move forward as quickly as possible to keep momentum to power through the next wave. Tacking angles are wider, so we sheet the sails accordingly.

How can we change the tune of the rig to better match the goals in this condition?

DSC 6153Spreaders- We need to add power to get through the waves, but make the boat easier to hike flat so that we can foot effectively. Shortening the spreaders will allow the top of the mast to fall to leeward more. This flattens the top of the mainsail and opens up the top batten. Now you can sheet harder without stalling the top telltale. Shortening the spreaders will also open up the slot between the main and the leech of the jib. A wider slot will help as the apparent wind changes on the waves. Raking the spreader tips forward will help power the rig up in the lower-middle sections of the mast. This allows you to vang harder without losing power or closing off the leech. Vanging harder helps keep the boat in a fast forward mode. For more info on spreaders in particular as a tuning tool, check out Spreader Adjustment
Another easy change if your strapped for time and don’t want to drop the mast to change spreaders would be to pin the turnbuckles 1 hole behind your flat water spot. This will effectively move the tips forward, but will not help with side to side bend.

clearwaterShroud Tension- This one is kind of a “no brainer”, but is worth repeating. In waves, we need to keep the boat powered up to punch through. Sailing with less shroud tension than your tuning guide recommends for a given wind strength is the correct thing to do. Yes, you will have to hike harder to overcome this change, but if you wanted to sail something easy, then maybe a keelboat is for you…

Mast Rake- This one is actually counter intuitive. Tuning guides are written for flat water setups and are usually striving to give a very neutral helm. To make a boat want to foot, one would think to rake the mast further forward. This is incorrect. The goal is to foot, but by raking aft the leeches of both sails get closer to the deck and open up more. This change means you can sheet harder without stalling. It also gives more bite to the rudder, and will help give the driver some feedback on which way the boat is trying to go as the waves pass underneath the hull. This added weather helm also forces the skipper and crew to sail the boat very flat which helps punch through the waves.

Other changes are quite small, but sailing with just a few extra wrinkles in the jib luff, easing the outhaul a touch, and maybe a little aft puller will all help make you fast in waves. A few final thoughts on setting up for waves. Tacking is much more costly and should be done selectively. When you do decide to tack, make sure you have a very large lane. Since the apparent wind is shifting more and boats are sailing “S” courses to best get through the waves, you need to be able to do the same and a thin lane is not a good place to find yourself. Lastly, with your new found speed, it is important to always make sure you are sailing on the favored tack or toward the favored side. Nothing is worse than sailing really quickly the wrong way!

Your boat is dialed, the coffee is gone. Gear up and get out there!

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