Melges 20 Tuning Guide

The following tuning guide is meant to be a good starting point when setting up your Melges 20. Depending on total crew weight, wind and sea condition and sailing style you may have to alter your set up slightly from what is given here. As you read this tuning guide, write down any questions you might have and we will be happy to discuss them in detail with you. The goal of this tuning guide is to achieve a rig set up that is fast in all conditions upwind and down. Your new North sails are designed with this “all around” philosophy in mind.


One of the most important items you and your team can do in preparing for high performance racing is to have your Melges 20 ready to race. Listed in this section are just a few items we feel are critical for success on the racecourse.


Make sure when transporting your Melges 20 that the keel bulb always sits perfectly in the keel bed of the trailer. If the boat is sitting where she belongs on the trailer you will find the bulb resting perfectly in the keel bed with space in the keel box both in front and in back of the keel. Also packing pre-cut foam between the keel edges / sides and the keel box will help prevent any movement of the keel when trailing. It is important to ensure that the keel fin is not touching the hull fairing plate prior to trailing. It is also important to ensure that the boat stays forward against the bow guide when trailering.


Class rules do not allow re-shaping of these items.

HULL – For traveling to regattas and general care of your new boat the investment of our bottom trailing cover and 1 piece top cover is well worth the protection it affords.

RUDDER – The rudder should always be removed when not in use and kept in its padded rudder bag. Remember to always put away dry.

KEEL – We just talked about taking care of your keel when the boat is on the trailer. When lowering the keel with the keel crane make sure you have rinsed out the keel box along with the keel guides. Make sure the keel box is free of any lines or padding. Also, make sure you keep the boat level when raising or lowering the keel to ensure the keel fin does not get damaged.


Believe it or not this is when most damage occurs to Melges 20s. When trailer launching make sure the keel box is well packed with padding, as the keel wants to shift as soon as the transom starts floating. To ramp launch you will need to use the keel retractor crane and just lift the keel about ½” to ensure you do not damage the hull fairing plate. Make sure you pad the keel well on the leading and trailing edges and make sure you take great care when using the keel retraction crane.

When using an electric hoist be sure to keep the boat level or maybe a few inches down in the bow. Again we are trying to protect the keel. Also by holding the bow down just a few inches we are protecting the spreaders from possibly hanging up on the hoist arm as the spreaders pass the arm. Keep in mind when you lower the bow the keel fin is vulnerable so care must be taken not to damage the keel fin. Make sure you use the aft leg of the lifting bridle attaching it to the transom to help keep the boat in a slight bow down attitude when lifting.

When launching on a hoist it is best to use the keel retractor crane. Hook the keel retractor to the lifting ring on the keel, make sure the lift ring is screwed all the way in the top of the keel. Take tension on the keel lift winch and securely tie off the winch handle to the horn cleat. Install the lifting straps to the lifting pins alongside of the keel utilizing a luggage tag type install. Also, install the longer aft lifting strap through the top rudder gudgeon at the transom using a rudder pin. When hooking up the hoist, put one of the lifting straps over the hook, then the aft leg, then the last lifting strap. Now when you lift the boat take care not to hit the spreaders on the hoist arm. It is best to have the boat at 90 degrees or more to the hoist arm and hold the bow slightly down to keep the rig off the hoist. Keep the keel padding in place until the keel is ready to be lowered and be sure to always hold onto the winch handle, keep all body parts away from keel and take great care when lifting the keel or lowering the keel.

It is a good idea to put some soap and water on the keel guide blocks and in the keel box to allow the keel to seat more easily. If the keel guide blocks do not line up fore and aft perfectly, put a body on the bow or the stern to help tilt the boat to line up the keel guides.


  • The factory Melges 20 comes ready to race. There are a few small class legal modifications that really help with sailing the boat.
  • With your spinnaker up at maximum hoist mark the halyard with a black permanent marker.
  • With your bow sprit fully extended also mark the tack line/bow sprit extender line. Make sure that you have the proper knot tied in the end of the line to account for it being tied to the tack of the spinnaker. It is best to tie the loop with about a 65mm or 2.5” loop to prevent the tack of the kite from binding on the bow sprit end plug.
  • The bow sprit is shock corded to retract. Ensure that the shock cord is adjusted so that it is just enough to retract the bow sprit and not retract with too much force.
  • Attach shockcord from the top of the forward stanchion to the upper shroud above the turnbuckle to prevent the spinnaker sheet from dropping in and catching on the shroud car.
  • Apply some number scales to the jib track adjustment locations. Place these above where the jib sheet lead comes aft and above the spinnaker bag sock on the port side. Number 1 should align with the traveler car pin when the car is all the way forward on the track. (front of car even with front of track)

Practice – Practice – Practice!

It has been said that each mark rounding can be worth a minute on the course. Now that is a reference between the first group and the last group of boats. That is a lot of time and a majority of it comes at the corners and the first few minutes of a race. Knowing how your Melges 20 accelerates off the starting line is something you need to practice. Sets at the windward mark are critical, especially if you want to gybe right away. Having the ability to pass between two leeward gate marks absolutely requires that you and your crew understand all three spinnaker takedowns, the Mexican, the windward and the leeward. You do not have to have rock star crews in the Melges 20 class to be successful; you do need to have a regular steady crew who are willing to practice. If we had “Time On The Boat Meters” you would find the top finishing boats in our class had the most accumulated time together sailing the Melges 20.

We highly recommend the spinnaker launch system with the retrieval line and spinnaker storage sock in the cockpit. The spinnaker take downs become quick, safe and easy.



As the Melges 20 comes almost completely ready to race straight from the factory there is very little to do to prepare your boat and mast to be competitive. With the mast down, pull all the halyards down and tie off at the bottom, also make sure the turnbuckles are set evenly with similar amount of threads showing at the top and bottom of the open body. Another thing we like to do is tie some light weight shock cord between the two lower shrouds around the front of the mast 6”- 8” down from their attachment points, also above the lower spreader between the intermediates and the diamond stays, and below the port spreader, also between the Intermediates and around the front side of the forestay about 12” below their attachment points. This keeps the head of the spinnaker from getting jammed between the shrouds and mast on hoists and keeps the kite from getting caught above the lower spreader on a take down.

Double check the spreader angle and symmetry: The following process is performed at the factory when doing the final rigging on every mast. Every mast is laser straightened so when adjusting the diamond statys make sure to keep them symmetrical. We are providing the process for future field checks. Using an angle finder, level the mast using the mast base, check the spreader sweep by placing a straight edge from tip to tip on the diamond shroud or use a string pulled tight.

For masts built prior do July 2013: The upper spreader should measure from the string to the aft side of the mast track 9.2cm and the lower spreader should measure 31cm.


Spreader angles too far forward makes the mast less forgiving and more prone to inversion with the spinnaker up in heavy wind.

For masts built after July 1st, 2013 utilizing dyform rigging we use the following spreader angles: The upper spreader should be set to 115 mm, the lower spreader set to 320 mm.

To make sure the spreaders are symmetrical, use an angle finder and find zero or level at the mast base, then check the angle on the port spreader and then the starboard spreader. Adjust as needed to make symmetrical and at the same time maintaining the correct sweep. Make sure that the turnbuckle adjuster has at least 4 turns onto the threaded stud. After setting the spreader angle adjust the diamond stays so that you have approximately 75mm (3”) of prebend in the mast and sight up the tunnel and adjust the diamonds to make sure the mast is straight side to side.

Once the rig is ready to step you can slide the mast aft, place the diamond stay over the keel and lock in the mast base to the mast step deck plate. Rest the mast in the mast support on the rear mast hold down bunk. Now, attach the Intermediate shrouds to the outer shroud cars, make sure the shroud cars are all the way forward on the tracks. Also, attach the lower shrouds to the inner sidestay cars and insure that they are all the way forward on the tracks. You will want to ease both intermediates and lowers out at least ¾ of the way on the turnbuckles to ease in attaching the forestay for the very first mast stepping.

Set the diamond stays so that there is approximately 75mm (3”) of prebend in the mast. By tensioning the diamond stays you put more prebend in the rig. The diamonds accomplish two important tuning tasks. First, they put prebend in the mast to better fit the luff curve in the mainsail and set the rig up to sail in a wide variety of conditions without needing a backstay. The other important aspect of the diamond stays is that they support the top of the mast when you are flying the Asymmetrical spinnaker. So, it is important to have enough tension on the diamonds to support the mast with the gennaker is flying. Refer to tuning matrix chart in PDF.

Before stepping the mast it is best to pre furl the jib furler so it is ready to go before stepping the mast. When furling the jib it should furl counter clockwise, so, to wind up the drum turn it clockwise until the drum has filled up with the furling line.

It is possible to step the mast alone but will be easier if you have some one pull forward on the forestay as you walk up the mast. Ensure that the mast base stays securely locked in the deck plate and does not come out as you are walking the mast up. Also, place a sail bag, or the provided keel fin cover over the keel to protect the mast and keel from scratching when raising and lowering the mast. The spinnaker sail bag also works well for this or the factory supplied keel fin cover.

Once the mast is up, attach the Forestay to the furling tang.


With mast stepped attach a 15M or 50’ tape measure to the main halyard and hoist to the top and lock off on the halyard latch.

Check to see that the mast is close to centered by measuring to the top of the outer shroud track at the same position on both sides of the boat. Tighten/loosen the upper shrouds on each side so that the mast is centered side to side.

With the main halyard locked in the up position, measure to the intersection of the transom and the bottom of the hull. The measurement should be 9310mm or 30’6-1/2”. Tighten or loosen the turnbuckle on the forestay to achieve this measurement.

Use the follwing setting for masts built prior to July 2013 with 1X19 shrouds.: You will have to adjust the upper tension when adjusting the forestay to maintain a constant tension on the uppers of 250Kg (550lbs) when checking the mast rake. The upper shroud cars should be in the max forward position for tuning at base. The diamonds should read a tension of approximately 95Kg (210lbs) when the uppers are set at 250Kg tension. Now, move the lower shroud car two holes aft and measure the lower shroud tension at 130Kg (285lbs) and sight up the mast on the aft tunnel side to insure that it is straight side to side. Dial in the settings to achieve the desired tensions with the shroud cars in the base positions.

Be sure to adjust the diamond stays to this setting with the tension gauge and to set the uppers and the diamonds to this tension to check the final mast rake.

Finally, recheck to be sure the mast tip is centered side to side and that the mast rake is 9310mm or 30’6-1/2”.

For masts built after July 2013 with dyform shrouds we use the following base settings using the Loos PT-1 gauge to check the tensions. Note that dyform will produce a higher tension reading for the same tension compared to 1X19. Set the uppers at 275kg (#39), lowers at 135kg (#28), diamonds at 175kg (#28).


he tension on the upper shrouds is critical to the upwind shape of primarily the jib and to a smaller degree the mainsail. For maximum speed it is important to adjust the shroud car position on the upper and lower shrouds depending on wind and sea conditions. The Melges 20 is designed with shroud tracks on ramps to facilitate ease of rig tune with minimal turnbuckle adjusting. As the wind increases you can move the upper shroud cars aft to increase rig tension and headstay tension. This in turn helps flatten the jib and depower the rig. So as you start to get overpowered start to move the upper shroud cars aft on the tracks. You will want to be all the way aft by approximately 16knots of wind. The class rules allow for purchase on the sidestay cars to allow the cars to be adjusted more easily. Visit for the latest shroud adjustment system set up.

The lower shrouds control the side-to-side sag or bend of the mast, how much the mast can bend forward in the middle, and the headstay sag. We set the lowers so that when both cars are all the way forward in approximately 7 knots of wind there is approximately 10mm of sag in the mast at the lower spreader.

After you have set up the uppers to the correct wind speed, sail the boat on both tacks checking the mast sag side to side and adjusting the lowers according to the wind speed. Also, check the mainsail depth. If the main is overbending or showing a wrinkle into the mast below the bottom spreader you either need to ease off the diamond tension a bit if the breeze is lighter or pull the lowers aft on the tracks if it is breezier. This will straighten the lower mast section and increase headstay tension flattening the jib. Generally we like to set up the rig so that the main sets up fairly flat with the lower cars at base when we are sitting on the windward side of the boat. With this set up we can pull the lower cars aft to power up the main when needed and not have to pull too much vang on to flatten the mainsail. Generally, if the mainsail is backwinding with the jib in max trim position,(top leach telltale just on the verge of stalling at times but flowing 100% of the time) then you need to bend the mast more to flatten the sail. You can do this either by tightening the diamonds or moving the lower shroud car forward. You will want to just take out the backwinding in the main and not go too far unless you are overpowered and are looking to depower the mainsail further.

Using the North tuning chart in the PDF as a guideline for shroud tensions in the given wind conditions, we then play the cars to fine tune the power in the boat. Generally, if you are all the way aft on the shroud cars and still need to depower the rig further it is time to tighten to the next step in the tuning chart. If you are never moving the cars aft on a beat then generally, you are too tight and should loosen to the next step down on the chart.

Note that in heavy wind it is important to move the lower shroud cars forward 2 holes from your upwind setting prior to going downwind to allow the mast to bend forward down low and reduce the tendancy for the mast to inverse bend with the gennaker up.


Speed targets are important on any keelboat. If you dial in a good feel for a target speed in all the different conditions you will find that your performance gains will be significant.

Upwind targets are more important than downwind but both will be helpful. Upwind we have developed the following target range that we have found to be fast. An important note is that you need to use an accurate through the water speedo and that a GPS based system will not be accurate enough.

5 to 7 knots of wind = 4.7 to 4.9 knots of boat speed

7 to 10 knots of wind = 4.9 to 5.1 knots of boat speed

10 to 13 knots of wind = 5.1 to 5.3 knots of boat speed

13 to 18 knots of wind = 5.3 to 5.7 knots of boat speed

15+ = > 5.7 knots of boat speed

Downwind the condition where targets pay off the most is in the low soak mode. This speed changes a lot depending on wave and wind conditions and is best called by the tactician for each given condition based on boat to boat performance.



Because the Melges 20 does not have a backstay or main traveler it is relatively simple to trim the main and steer requiring very little movement by the helmsperson. Like other boats main trim on the Melges 20 is keyed off the end of the top horizontal batten. In light to moderate air we trim the main so that the telltale on the top batten is stalled about 25% of the time (the second telltale from the top -at the second batten, is flying 100% of the time). As the wind increases both telltales will fly all the time. In light to moderate air the back end of the top batten should be parallel to the centerline on the boat, in heavy air it will be pointed out as much as 30 degrees. With the square top mainsail on the Melges 20 it is important to not over trim the mainsail. Twist is your friend, when it doubt, ease it out to get the boat going through the water. Also, keeping the mainsail trim soft and very twisted sometimes in order to sail the boat very flat can be very fast. It is important to experiment with given heel angles and main sheet tension in different conditions to see what is working the best.

Following is an overview of each main control and how it should be adjusted.


The Melges 20 likes to have some power down low in the mainsail so we like to keep the outhaul eased about 10-25mm in from the band In most conditions. In the heavy air setting we tend to pull the outhaul out to the band to flatten the sail, especially in flat water. In rougher seas it may be fast to keep the outhaul a bit looser to make the main fuller down low.


We use the vang upwind as soon as the boat is overpowered. At the early stages of being overpowered we simply snug the vang to help induce mast bend and flatten the mainsail. As you become more overpowered we pull the vang harder to flatten the mainsail and vang sheet. Downwind adjust the vang so the top batten telltale is always flowing, twist is generally good. Generally the vang with the slack taken out of it upwind will be too tight for downwind sailing. It is a good idea to put a number scale on the boom next to the vang track to keep track of fast settings and for an approximate downwind setting. A medium vang setting for the offset reach leg and then a loose setting for the run provides the best performance.


We use the Cunningham on the Melges 20 as another one of the depowering tools. We pull on just enough to remove any horizontal wrinkles in the sail as soon as we start to get overpowered. As you become overpowered experiment with a very hard Cunningham to flatten the main, pull the draft forward and twist open the head. Again, different wave conditions warrant different settings so you must experiment to find the fast setting. Downwind the Cunningham should be off.


Because the jib on the Melges 20 is a high aspect sail (tall and skinny) it is very sensitive to small adjustments in jib sheet tension. Tightening or easing the jib sheet 1/2” can have a big effect on boat speed and pointing.

The Melges 20 jib halyard is set up on a halyard lock system similar to the mainsail. Some adjustment of jib height may be required using an extra shackle on the head of the jib. The standard setting sets the jib so the foot is just off the deck in light air and just touching in more breeze as the shrouds are tightened and is generally a good setting.

Generally in light to medium breeze set the jib lead so that when luffing slowly into the wind the luff breaks evenly. As the wind builds you will want to move the lead aft to flatten the foot and twist the head of the jib to depower.

It is a good idea to put some numbers and dashes corresponding to the different jib car positions on the track. We like to have a dash and number at each hole that the pull pin plunger will seat into. The first dash and #1 will start at the 4th hole back from the front end of the track, at this position the front of the car will be flush with the front of the track.

The Base setting for the jib car is #3. This puts the car in a position where the aft end of the car splits the second bolt from the front of the track.

In winds below about 15 knots it is legal to inhaul the windward jib sheet to narrow the sheeting angle on the jib. This is legal to do and is sometimes fast. It only requires a slight tension on the windward sheet to make a noticeable difference. Take care not to over inhaul as this will be slow. In light to medium conditions we inhaul as much as 25mm on the clew of the jib. It is best to mark the jib sheets in a way that you can easily replicate settings from tack to tack. When in doubt, ease it out! Note: On the newer jibs we’re finding that inhauling is rarely required so take care when inhauling.

We have placed a telltale on the upper leech (near the spreaders) of the jib to help you judge how tight or loose the sheet should be. The general rule of thumb is to trim the sheet hard enough so that the upper leech telltale is just on the edge of stalling, but never stalled. Just as with the mainsail it will be easy to stall the telltale in light air and very hard to stall in heavy air even with the sheet trimmed very hard.

Jib Cloth Tension

Adjust the small line at the tack of the jib so the luff of the sail has some slight wrinkles coming off it. It will be necessary to change the tension depending on the wind speed to keep the wrinkles the same in most conditions. In very heavy air, tension the luff so that the sail is smooth. In flat water it will sometimes be fast to carry some horizontal wrinkles off the luff.


Be sure that your leech cord is not too tight. It is very easy to put a lot of tension on the cord in heavy air and have it too tight in light air. The key is to just stop the flutter in the leach if there is any.


Spinnaker trim on the Melges 20 is much easier than that of a conventional poled boat. There are a few tricks that can make you faster downwind and make your sail handling easier.

You will want to set up the spinnaker sheets to always gybe inside the luff of the kite. So the tack line would be over the top of the spinnaker sheet as it comes aft to the kite. When rigging – “tack over sheet” is your reminder.

Always trim the kite so it is on the edge of collapsing on the luff, it is not fast to over trim the kite.

Gybing the Asymmetric

On the gybe, the fastest method is to have the trimmer ease the kite as the boat heads down, then the forward crew starts to trim the new sheet as quickly as possible to fill the kite on the new gybe. This is called the pre gybe and requires the driver to bear away to almost dead down wind and wait for the clew of the kite to be about half way from the headstay to the side shrouds before turning onto the new gybe.

Mexican Gybe

In heavier wind the Mexican style gybe works the best. It is also best to sail with the jiboutdownwindinplaningconditions. So, the trimmer will want to trim the jib in so that it is snug, the driver goes into the gybe straight away, the trimmer trims the kite in as the boat heads down, the kite fills and backs into the tight jib once the wind hits the kite and jib on the other tack, trimmer blows off the sheet and trims the new sheet as quickly as possible and releasing the jib sheet as soon as possible. When performed properly the kite will blow across the headstay and fill with a pop on the leeward side.

Spinnaker Sets

Forward crew pulls the spinnaker halyard up and the second crew pulls the tack/ pole out. Or, vice/verse, either way works well.

Spinnaker Douse

There are three types of takedowns: the windward, the leeward, and the “Mexican”.

The windward douse is used when doing a port rounding and you are approaching the mark on port tack. The “Mexican” is for rounding a mark to port but your approach is relatively shallow on a starboard tack. The leeward douse is for rounding a mark to starboard while on starboard tack or when you approach the mark at a very sharp angle while on starboard tack and you will have to gybe quickly around a mark leaving it to port.

For the leeward douse, you can either grab the lazy sheet off of the clew, or grab the sheet just above the anti hiking pad to strap the foot. The helmsperson then must bear off slightly, the clew should be pulled in under the mainsail to prevent the kite from blowing over the leech of the mainsail, and then the tack line must be blown off completely. The halyard should then be fed down as the crew gather the spinnaker. The key here is to maintain the tack and foot of the kite and keep it out of the water, also watch for the kite blowing behind the leach of the mainsail.

For the windward douse, the skipper can sail low, while the crew start to trim the windward sheet to pull the kite around to the windward side the forward crew should blow off the tack to unload the pressure off the kite. The clew should be grabbed inside the shrouds and start to stuff the kite in the bag gathering leach first for about 1/3 and then grab both. Steer under the foot to keep the kite on the deck.

For the “Mexican”, as you approach the leeward mark on starboard, the helmsperson should bear off into a slow gybe, the trimmer will over-trim the sheet as the boat gybes to port. Just as the boat is headed directly down wind and the mainsail begins to gybe, blow off the halyard. The spinnaker will blow against the rig and fall on the deck. When the sail is 2/3rds the way down release the tack and stuff the spinnaker in its bag. Practice of these three douses is vital to success on the racecourse.

Spinnaker Douse with Take Down Line

We highly recommend using the take down system on the Melges 20. This system adds greatly to the ease and simplicity of taking the gennaker down. With this system the entire process is simplified. The middle crew typically starts to inhaul the takedown line while counting down 3-2-1 and at zero the forward crew release the gennaker halyard and the tack line guiding the lines out so they do not snag. We always ease the halyard first, even on leeward drops. On a leeward drop after the halyard is eased and the tack released the forward crew should tend to the foot and tack of the kite to keep it out of the water. The driver needs to bear away to flatten the boat. The forward crew can help to stuff the last part of the kite into the sock.

On the set, it is helpful to pull the kite forward to the front of the sock to help it come out easier. Also, tending the kite halyard so it runs out freely helps insure a clean set.

Crew Positioning

Generally in light wind, you want to sit as far forward as possible between the stanchions. Keep in mind that you are not allowed to be in front of the mast. Downwind, you will want to also sit forward and heel the boat to windward as soon as you have enough pressure to sail deep. As the wind builds you want to move the weight aft upwind so the middle crew is centered on the mainsheet swivel. Downwind when planing everyone slide aft as far as possible unless you are in marginal planing conditions. Then it is best to keep the weight more centered and move the weight fore and aft to get the best feel in the boat and keep her planing as long as possible.


  • Make sure the rig is set up for the wind and see conditions
  • Keep the outer shroud cars max aft
  • Big ease on the kite or blow off the sheet in extreme puffs and waves with bow bury
  • Mainsail sheeted in with vang off or if main is eased have some vang on


The Melges 20 is one of the most exciting new boats available today with rapidly growing fleets and excellent one design racing. We hope all of the tips we mentioned are helpful to your Melges 20 sailing program. Let us remind you that these are the most important and obvious helpful hints that we have provided. Our experts will be happy to go further in detail with you anytime.

Rev R12