Year 2000 --Banks Sails Santana 20 Tuning Guide

Chris Winnard  ---  Lance Purdy


Congratulations on the purchase of your new Banks Santana 20 sails.  Banks has been the dominant sailmaker in the Santana 20 Class for years because we care about the class and the people who use our sails.


In preparing to write this tuning guide, we dug into our S-20 ‘Wet Notes’, dredging up practical rig tuning and boat preparation information that we believe lead to success.  After witnessing some very unorthodox methods of boat preparation, used by ourselves as well as the competition, we decided that this guide should focus on the basics.  Keep in mind that what’s useful and important about this guide, is not so much the numbers, but the way in which the boat is set up.  Plain and simply, if it is a pain in the butt to adjust the rig, you won’t do it!


Wipe down the shrouds and spars with Acetone, while visually checking all sheaves and fitting for excess wear or other signs of potential breakdown (probably the most important thing we ever do!).  If the sheaves appear to need lubrication, use a dry lubricant like McLube.  Never use oil or grease as they simply attract dirt.  After examining the rig, measure the distance from the upper shroud tang bolt to the spreader and make sure they’re even.  At this point, we attach six-inch strands of cassette tape to the uppers (about 7 feet up) and one to the backstay.  The tell tales on the uppers are used by the spinnaker trimmer and the helmsman to square the pole and detect subtle windshifts.  The one on the backstay is used by the bowman to call possible shifts as he looks back for breeze


 First, equal out the turns of the upper shroud turnbuckles on the shroud studs and attach the toggles to the chainplates.  The end of each stud or t-bolt should just be showing through the inside of the turnbuckle.  Next, attach the aft-lowers.  We leave the forward lower shrouds loosely tied to the mast.  This reduces the risk of catching a shroud on something or bending a toggle that was cocked near the chainplate.  Next ease the mast to the aft and insert the bolt at the step.  Finally, have someone grab the forestay and someone get under the mast and hoist it.  Once the stick is up, attach the forestay, lowers etc. and run the halyards.  Leave the lower shrouds slack and hand tighten the uppers.  At this point, we recommend that you take some time to relax, before finalizing the tune.


 Mast Rake:

To induce weather helm while steering upwind, the proper amount of mast rake must be set.  To measure mast rake on most boats, you simply attach a tape measure to the main halyard, pull it up until it two-blocks, then measure to a point on the transom or deck.  Because Santana 20’s have so many different mast cranes, halyard sheaves and halyard shackles, the aforementioned system will not produce consistent number from boat to boat.  For this reason, we advise a measurement method that is a bit more complex but extremely accurate.

First, measure the distance from the mast butt to the top edge of the lower black band to assure that it is a class required 22”.  Now, supporting the mast with the spinnaker halyard, disconnect the forestay and bring it back to lay flush against the forward face of the mast.  Put a mark on the forestay that corresponds with the top of the black band and the 22” measurement.  Now, reattach the forestay and ease the spinnaker halyard.  Finally measure from the center of the forestay clevis pin to the mark you’ve made on the forestay.

Recommending Rake Setting = 51”-52” from the center of the forestay pin to the mark

If you are racing with a light crew <450 lbs. The 51” number will work better for you.  If you have regular sized crew of 450 lbs, use the 52” mark.  We have found that to achieve sufficient rake without inducing unwanted mast bend, it may be required to file down the aft edge of the mast butt as much as a third of an inch.

Centering the Mast:

The technical idea behind centering the mast is to align the mast with the keel so that they are on the same plane.  There are many ways to do this but we have faith in the builder and trust that everything is reasonably square.  Upon this assumption we use the following method to center the mast.

Measure 7-8 feet back from the forestay pin along the shearline of the deck and make a mark on either side of the boat on the rail.  These marks are forward of the shrouds, and being equal, allow for accurate side-to-side measuring.  Hoist a measuring tape up the jib halyard, leaving the knot or shackle at least four inches shy of full hoist.  The jib halyard is should be used as opposed to the main halyard, because, on a fractional rig, you only have side to side (centering) control of the mast from the upper hounds down.  The halyard is left four inches shy of being two-blocked to prevent twisting the tape toward one side or the other.  Next, alternately measure down to each black mark and adjust the upper turnbuckles until the distances are equal.  Leave the tape hoisted.

Rig Tensioning:

From each of the four turnbuckles attached to the main chainplates, measure up four feet and mark each shroud with a small piece of tape.  The purpose of the tape is to mark spots to attach the Loos Tension Gage for consistent measurements.  Then slowly tighten the uppers, one half turn at a time, until you reach a base setting of 22 on the Loos Gauge.  Using alternate half turns is critical to keep the mast centered and to prevent locking in a lateral bow.  Once the uppers are at 20, use the same method to bring the lowers up to a setting of 10.  During this process, periodically check that the mast is centered, using the still hoisted tape.

Next, sight up the mast groove looking for any waivers or a lateral bow.  Most discrepancies can be tuned out by adjusting the lowers in half turn increments.  Once the mast is straight, bring the lowers up to a setting of 15, again by using half turns.  Finally, check the mast one more time to assure that it is both centered and straight.  If things are not as desired, a couple of problems may have developed.  You may have miscounted your turns or your spreaders may not be even.  The latter reinforces the need to measure the spreaders against the shrouds prior to stepping.



We have used 6-9 knots to represent our base setting.  Between races, we routinely change our tune to optimize the rig for the wind speed.  However, when first learning, we recommend that you set your rig for the expected wind range and only make changes if conditions change drastically.


       UPPERS                                         LOWERS

WIND                                     Loos       Loos                            Loos       Loos

                                                Mdl. A,  Mdl PT-1                     Mdl. A     Mdl. PT-1

0-3                                           33           24                                15             7         

3-6                                           33           24                                17             12

6-9       (Base Setting)             33           24                                22             14

9-12                                         33           24                                26             16       

12-15                                       35           26                                32             22

15+ w/Genoa                           36           27                                34             25

15+ w/Jib                                 33           24                                32             22



Your Santana 20 Banks Sails are designed to work efficiently through a wide range of wind and water conditions.  To do this, the shape of the sails has been engineered to be extremely sensitive to changes in rig tension, which has already been discussed, and, more importantly, to sail trim.

Basic Upwind Premise of Sail Trim


The basic idea when sailing upwind to start with a full and powerful setup for light wind.  Then, as the wind builds, progressively de-power your sails by using controls that adjust flatness and twist.

Key Trim Controls

Backstay:                     Controls the mid to upper main flatness through mast bend, affects the flatness of the jib through control of forestay sag.

Aft-lowers                    Affects jib flatness by control of forestay sag and increases the

                                    depth in the main.

Jib Sheet Tension            Controls jib flatness

Jib Car Position            Controls jib twist

Main Outhaul                Controls flatness of lower main

Main Sheet Tension            Affects Main Twist      

Main Traveler               Also affects main twist.   

Additional controls are:

Jib Halyard                   Affects jib draft position

Main Cunningham            Affects main draft position

The jib halyard and the main cunningham are not listed as primary sail controls for the following reason.  Over tensioning, either the jib halyard, the cunningham, or both, is a common problem with many sailors that should not be reinforced.   This condition leads to a situation where the other trim controls become less effective because it inhibits the sails’ ability to freely change shape.  For most conditions, the jib halyard and the main cunningham should be tightened just enough to remove the major wrinkles in the front of the sails, and no tighter.  In general, it is safer to be too loose than too tight.  Leaving a hint of wrinkles is usually a safe way to guarantee that the halyard or cunningham is not over tensioned.  The only exception to this rule is during conditions when the boat is difficult to control such as in heavy chop or heavy, puffy air.  In these conditions the cunningham and halyard should be tensioned until all wrinkles just disappear.

Light Air, 0-5 Knots

The key to light air is to keep your sails as full as possible without stalling the airflow.   Keep the mast straight and the forestay sagged by using essentially no aft-lowers or backstay.  Ease the Genoa sheets so that the sail can breath and so the foot is not strapped against the shrouds.  In very light air, the foot could be as much as a foot from the shrouds but 6-8 inches is usually sufficient.  As the wind increases, sheet tension can be increased and the foot brought further in.  However, avoid the tendency to bring it too far in, too soon.  Adjust the genoa cars so that the top of the sail (near the spreaders) is about the same distance from the shrouds as the foot.  Move the cars forward if the top is too wide, move them back if it is too close.  The general rule of thumb is to move the cars forward as the wind lightens, but be careful.  If the cars are moved too far forward, the upper leech with close and stall the sail. 

Ease the main outhaul until it is essentially loose and the clew is at least 2” from the black band.  Pull the main traveler about 2 inches above centerline, then tension the main sheet until the boom is on the centerline of the boat.  If the telltale on the top main batten is not flowing freely, keep the boom on centerline, but increase twist by pulling up the traveler and easing the sheet.  As the wind builds use more sheet and less traveler.

Medium Air, 6-12  Knots

In these conditions worry about stalling the sails takes a back seat to maximizing power and increasing point.  The mast should still be kept straight and the forestay fairly loose, so use only enough backstay to keep the rig and the forestay from bouncing.  Aft-lowers should still be loose or just pulled snug if the conditions are choppy.  Tension the genoa sheet until the sail is 1-2 inches from the shrouds at the foot.  Adjust the cars until the sail is 1-3 inches from the shrouds at the spreader tip.  During puffs, increase the genoa sheet tension for point.  During lulls, decrease sheet tension for power. 

Pull the main outhaul out until it is within about ˝ inch of the black band.  To increase point, ease the traveler and pull on more main sheet until the upper main tell tale stalls about 50% of the time.  During puffs and lulls, play the mainsheet, not the traveler.  During lulls, ease the sheet until the top tell tail flies, during puffs, increase sheet tension until it stalls.

Upper Genoa Conditions, 13 to somewhere between 16 and 20 knots.

In these conditions the boat is overpowered with the Genoa but it still faster to keep the larger headsail as opposed to dropping down to the jib.  The point at which to step down to the jib depends on crew weight and water conditions.  At one extreme, if you have a light crew and the water is flat, you may be better off changing to jib at wind speeds as low as 16 knots.  Alternatively, if you have a heavy crew and the water is choppy, holding the Genoa in up to 20 knots may be optimal.

In any case, when holding the genoa in overpowering conditions, some steps must be taken to significantly de-power the sailplan.  Tension the genoa sheet until the foot is tight against the shrouds but not stretched.  Set the genoa cars so the upper leech is 2-4 inches from the spreaders.   Pull the main outhaul all the way to the black band.  Tension the backstay until the main becomes board flat, and just shows a hint of over-bend wrinkles (wrinkles leading from the clew to the mast).  Snug up the Aft-lowers until the wrinkles disappear.  Set the main traveler at centerline and ease the main sheet until the upper leech twists off by 10-15 degrees.  To keep the boat flat in the puffs, ease both the main a genoa sheets slightly.   Bring them back in during the lulls.  The idea behind this set up is board out the main and play the sheets to reduce heeling, while keeping the genoa fairly powerful to keep the boat driving.

If you have done all of the above and are still overpowered, you must begin to really flatten the genoa as well.  Move the genoa cars increasingly farther aft twist the leech as much as 6” or more off the spreaders, or until the upper part of the genoa is actually luffing.  Tighten the forestay by increasing aft-lower and backstay tension in tandem.  They must be tightened in tandem because each time you tighten the aft lowers you decrease mast bend and power up the main.  Therefore, the backstay tension must also be increased to keep the mast bent and the main flat.  Continue this process until you are under control or you are sure that one more pound of backstay tension will pull the rig apart.  Continue to ease the sheets in the puffs, sometimes drastically.

Jib Conditions, somewhere between 16 and 20 knot and up

Right on the break where you change to your jib, whether it is 16 knots or 20 knots, you are going to have to make some adjustments or risk being underpowered.  Set the jib cars at their farthest forward position.  Trim the jib hard until the leech stands straight up from the clew, but does not close at the top.  Set the aft-lowers so that they are about 75% as far back as they were with the genoa, which may induce over bend wrinkles.  Ease the backstay until the wrinkles disappear.  Set the main traveler at centerline and trim the main hard until the upper telltale just begins to want to stall.

If still underpowered, ease the aft-lowers and backstay.  If overpowered, or if the wind continues to build, tighten the aft-lowers and backstay in tandem as described above and move the jib cars back.  As usual, play both the main and jib sheets.  If you are still overpowered and the backstay is as tight as you can stand it, drop the main traveler 4-6 inches and continue to play the sheets.  If at, at any time, more than 50% of the main is luffing, it will be faster ease the jib and foot.


Basic Spinnaker Trim

There are lots of sources for spinnaker trim, so we will only touch on basic trim briefly. 

Set the pole fore and aft so that the leading edge stands as vertical (straight-up) as possible.  If the edge is leaning toward the bow, ease the pole forward.  If the edge is leaning aft or outboard, move the pole back.  In general, farther aft is faster than farther forward, so if in doubt, try moving the pole back and see what happens.

Set the pole height so that, when you ease the sheet, the leading edge begins to break at about 6O% of the way up from the clew.  If the pole is too low, the leading edge will break near the top making it impossible to keep the shoulders open and leading to a pinched look in the top of the sail.  If the pole is too high, the lower edge will break first and entire sail will tend to easily collapse making it difficult to trim.

Light Air, 0-5 knots

In these conditions, the boat cannot be sailed on a dead run and you will produce much better VMG if you come up to slight reach.  How far to come up varies drastically with wind speed but a good rule of thumb is to sail as low as can so long as the spinnaker constantly stays full.  If the spinnaker is difficult to trim, or if it keeps collapsing, you need to come up.  Remember that you will constantly have to trim and ease the main as you change course.  Ease the backstay and aft-lowers completely.  Set the head of the chute so that it is about 6 inches from full hoist.  Position crew weight so that it is centered, forward and low.  The skipper should be in front of the traveler and the forward crewmember near, or in front, of the shrouds.

Lower Medium Air, 6-10 knots

In these conditions the S20 should can be sailed within about 5 degrees of DDW.  Move the pole back to within about 6-8 inches of the shrouds.  The main should be all the way out with just enough vang to keep the upper leech closed.  Keep the crew weight low, forward and roll the boat about 5 degrees to weather.  When a puff hits, allow the boat to roll further to weather and head deeper.  When a lull arrives, allow the boat to roll back up and head up.

Upper Medium Air, 10-15 knots.

In these conditions the spinnaker should still be set for full power and the boat can be driven DDW at all times.  In order to add a bit of stability, make sure the spinnaker halyard is at full hoist and center the crew weight.  Move the skipper just behind the traveler and the forward crewperson to the hole.

Heavy Air, 15 knots and Greater

In these conditions it becomes much more difficult to keep the boat under control and stability becomes a major concern.  To keep the shoulders of the Spinnaker from bouncing from side to side, choke it down by lowering the pole, pulling on the leeward twing and over-sheeting until the foot until it is just touching the headstay.  The pole may be let slightly forward, but not much.  Letting the pole too far forward will add too much depth to the chute making it unstable and the boat prone to roll.  For safety, keep some tension on both the aft lowers and the backstay.  Continue to drive DDW and balance the helm with crew weight, this typically means moving weight to the side of the boat away from the pole (the main side).   The skipper can slide back until he or she is comfortable, but the rest of the crew should try to stay forward because moving weight back makes it much harder to steer.  When the boat begins to achieve such speeds that it is actually catching and plowing into waves, then the crew must move their weight drastically back.  When this happens, hang on and pray you don’t have to gybe.


Banks’ Full Battened Main 

Most of the other major sailmakers now build their mains with only one or two full battens.  While Banks has continuously improved our main, with innovations such as custom tapered battens (built specifically for the S20) and lighter, smaller batten pockets, we have steadfastedly held to our full batten design for two solid reasons. 

One, full battens are just plain faster.  There is nothing more efficient than a full battened main when it comes to holding a fast, stable shape.  In puffs and heavy air, the battens resist the tendency for the draft to float aft and keep the leech open.  In chop, the battens stabilize the entire sail and keep the boat driving.

Two, unparalleled durability.  There is no question that Banks mains last the longest.  If you look at a two year old partial battened main, you typically see a crease developing that runs from the clew, on up through the front of each batten pocket, and to the head.  This breakdown of the sail shape is terrible detriment to speed, often making it impossible to flatten the sail properly, control the draft, or keep the leech open when overpowered.  You will never see this problem on a Banks main.  The full battens effectively transfer stress from the leech area to the mast.   The full battens also drastically reduce flogging when tacking and luffing.  The result is a main that stays fast for years.

While Banks full battened mains are easy to trim in moderate wind or higher, we sometimes get questions from new Banks owners related initial difficulties with trim in little to no wind.   One of the common problems is a condition where the battens do not “pop through” or stay “inverted” after a tack.  If this happens check the following.  First, make sure the battens are not over tensioned in the pockets.  The battens should just fit snugly, no tighter.  Next, make sure your mainsheet and vang are not too tight for the conditions.  This can inhibit the ability for the sail to freely develop the kinetic energy necessary to “pop” the battens through during roll tacks and roll gybes.  Spraying the leech of the main with McLube also helps in this area.  Finally, and most importantly, make sure you are properly executing your roll tacks and roll gybes.  A little practice in this area will not only help you with main trim, but will improve your speed in general.

Another problem new Banks owners sometimes have is difficulty keeping the main from becoming too flat in light air.  If this happens to you, try the following.  First, make sure your battens are not under tensioned.  A batten with no tension at all will remain perfectly straight in light air, producing no shape.  Next, check your basic sail controls.  The outhaul should be well eased.  The vang and the sheet are not too tight.  Just a little bit of cunningham tension often helps produce shape and bring the draft forward.  Finally, make sure your lowers are not too tight for the conditions (refer to tuning chart).  Loosening the lowers creates a little more depth in the center of the rig, which can significantly help induce shape in the main.