|Santana 20 Tuning Guide|
|Tuning your Santana 20 involves 3 basic steps. First, get the mast centered
side to side in the boat. Second, get the proper mast rake, and third, correctly control
the amount of mast bend and headstay sag you have while sailing.
Always start with making sure the mast is centered side to side in the boat. This is not as easy as it sounds because no boat I have ever seen is perfectly symmetrical. The most common way is to pull a tape measure to the top of the mast on the main halyard, and measure down to each side of the boat. This will get you in the ball park but rarely will it be really accurate. A much better way it to take the boat out of the water and check it while on the trailer. Get hold of a good carpenters level, or better still a transit, and a couple of jacks you can put under the trailer. Hold the level side to side on the bottom of the boat just aft of the keel, and jack the trailer up or down until the boat is level. Now, hold the level vertically on the keel near the trailing edge and see if the keel is straight up and down relative to the bottom of the boat. Note that I said relative to the bottom of the boat. You can not use the shear line or anything on the deck to check to see that the boat is level! Once you see if the keel is on straight or not, you will have to make the decision of whether or not you want to mess with trying to refit it. Unless the keel is obviously off, which should be evident from just a careful visual inspection, I wouldn't worry too much about it. The boat is never going through the water perfectly level anyway. What is important is that the keel, rudder, and rig all line up in the same plane. Go back and re-adjust the trailer until you get the keel itself dead straight up and down using the level or by sighting with the transit. Now stand back a ways behind the boat and sight down the trailing edge of the rudder to the trailing edge of the keel. You want them to line up also! The final step is to check the mast to make sure it is in the same plane as the keel. Still standing 50'to 100' behind the boat, hold the level vertically at arms length and sight the mast. By holding the level so that it lines up right against the lower part of the mast you will be able to see how far off the top of the mast is. Trust your eyes! They are "extremely accurate at seeing what is straight and what is not. Using this method you can certainly get the top of the mast within 1/2" of perfectly lined up with the keel, and that is what is important. What the hull does in between doesn't matter too much as long as it is close. If you have a transit you can get even more accurate by adjusting the rig until you can sight from the bottom of the keel, up the trailing edge, and all the way right up the luff groove to the top of the mast.
Now for the rest of the rig. Start by using a tension gauge and setting the uppers with about 275 to 300 lb. when the top of the mast is where you want it. Put on just enough backstay to take the slack out, and have the aft lowers completely loose. Sight up the groove in the back side of the mast and adjust the lowers until it is straight. The bottom of the mast is fixed, the top has been centered, so all that is left is to get the middle in line. Once this has been done use
the tension gauge and tighten or loosen each side equally until you have 325 to 350 lb. in the lowers. Light crews may use a little less while heavier crews can use a little more. All the time keep checking to make sure the mast is staying straight. In light and medium air the tension doesn't really seem to matter as long as the mast is straight. But we have found we go much better in heavier air with this set up. I want to see the mast stay straight side to side up to the point where we are starting to get over powered. Once we have to start dumping the main or moving the traveler down, I want to see the top of the mast start falling off a little. This really helps in puffy conditions. When we tried sailing with a tighter rig the boat was noticeably slower in heavy air. Every time we got hit by a puff the boat would heel over, slow way down, and slip sideways! When you let the top fall off in these conditions it depowers the main, and opens the slot. The boat will accelerate or "squirt" in the same puffs. Sailing with a looser rig is fine in light and medium conditions, but in the 12 to 20 knot range it seems a little slow (the mast sags too far of to leeward). When the wind really comes up you have a real possibility of loosing your mast is the rig is too loose!
The final step before sailing is to set the mast rake. Pull a tape measure to the top of the mast on your main halyard and measure down to the center of the hole on the backstay chain plate. The old measurement we used was 29'2"on boats with old style decks. On boats with the new style decks the measurement is 31’ 1" measured down to the intersection of the hull and centerline of the transom. This measurement is easy since it actually works for either style deck. Rake is hard to set from boat to boat because there are so many variables. The exact location of the mast fore and aft may differ slightly, the location of the main halyard sheave, and the size of the halyard shackle and thimble can all be different. Even if they are not, the correct rake for one mainsail may not be right for a mainsail made by somebody else. The rake you carry is determined by the amount of weather helm you want, and is controlled solely by the length of the headstay. Sails with different amounts of camber, and different leech profiles, will produce different amounts of weather helm. So use this measurement as a starting place, and then go sailing. Try to sail in some 6 to 8 knot wind with normal trim (about 10 degrees of heel) and adjust the headstay length so you have just a small amount of weather helm. If you need more, put in a little more rake, and if you need less, straighten the mast up a little. Remember that more mast rake generally depowers a boat, and that weather helm means you are dragging the rudder through the water sideways. Try to use as little as possible. It may be harder to steer the boat because you have less "feel" but if you work on sailing upwind without relying on a lot of helm pressure, you will be faster!
O.K., you have the basic rig perfect for your conditions, and your sails. Now what to do with those aft lowers? To start with, you have to convince yourself that they have nothing to do with mast bend! And you have to really believe it. If all you want to do is change your mast bend, why bother with aft lowers. Just use the backstay!
The aft lowers are for controlling headstay sag. If you are sailing with the main trimmed perfectly, but find that you aren't pointing as well as other boats, it is probably that the headstay is sagging too much, making the genoa too full. If you just tighten the backstay, it may make the headstay tighter, but now the mainsail is too flat. The answer is to pull the aft lowers on a little tighter, which further increases headstay tension, and at the same time, straightens the mast back up. Now you have a tighter headstay which means a flatter genoa, but the mast is still bent the same as when you started. In light air, when you want the headstay to sag a little so that you have a nice full genoa, you will have to sail with the aft lowers all the way off so that when you put on enough backstay to get the main correctly shaped, the headstay will be as loose as possible. I have known people who think the aft lowers should be tight in light air because they want a full main, and loose in heavy air so they will have a flat main. Then they wonder why they go so slow in light air, and why they can't point when the wind comes up!
For a general rule, the harder the wind, and the tighter you have your backstay, the tighter you must have your aft lowers. To be more specific, any time you want the headstay tighter, use more backstay and more aft lower tension, and when you want the headstay looser, use a looser backstay and aft lowers. With a good 12 to 1 backstay you can always get the main flat enough by just pulling harder, no matter how tight you have the aft lowers. When it is really blowing we will sail with the aft lowers as tight as they will go (which means somebody pulling with both hands about as hard as they can pull), and still get the top of the main to go board flat. Without adjustable aft lowers you will never be able to get headstay tension when the wind blows because you will be very limited in how much backstay tension you can put on. If you pull it on too much, you will over bend the mast and turn the main inside out long before the headstay gets tight.
The biggest complaint I hear from people is that they can't point. If you have a good set of sails, sheet them in properly, bring the boom up to centerline and still think this is a problem, I can guarantee the problem is headstay tension. And there is only one way to solve it. Adjustable aft lowers. Trying to sail your boat competitively without them is an effort in futility. You have to be able to adjust the shape of the headsail the same as you have to be able to adjust the shape of the mainsail. Any given headsail has a particular amount of sag that it is designed for, and you have to sail with that amount if you want to get the best performance out of it. I'm sure you wouldn't try to race your boat without being able to adjust your mastbend, and trying to do it without adjusting the headstay tension is just as bad.
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