Tuning Guide

How to Win in a J 80

Shore Sails Tuning Guide was written to help you get the best performance from your J 80. Shore Sails has been sailing J 80's since the boat was first introduced. Our commitment to the class, and to its sailors, sets us apart from any other company in the sailing industry.

Welcome to the Shore Sails Program, the relationship we are about to build is of utmost importance to us. We look forward to working with you. We believe that if you follow our tuning guide and ask questions of our J 80 experts, your sailing experience will be simpler, more successful, and most of all, more fun.

The measurements and the settings included in this guide are ones that we have found to be the fastest for the J 80. Since crew wind and sailing conditions vary, you may find slightly different settings are better for you.

Preparation

You should go over certain areas of your J 80 whether it is used or brand new and out-of-the-box to ensure your boat is race ready. Many of these tips are applicable to the preparation you would do for any one-design racing boat.

Hull
A clean, fair underbody is essential for fast racing finishes. Be sure that the bottom is smooth and free of any bumps or hollows. If your boat is not dry-sailed, a very hard bottom paint is recommended for racing. There are several racing bottom paints available that have good anti-fouling properties. Occasionally, go over the bottom with 600 grit wet sand paper to maintain the smoothest finish. Contact your local boat yard, ship chandlery or Shore Sails loft to find out about the latest paints.

Keel and Rudder
Wet sand your keel and rudder to a smooth, fair finish.

Mast
Remove the spinnaker halyard cleat from the mast. Attach a turning block to the padeye on the starboard side of the mast base to lead the spinnaker halyard to the cockpit. We have found this works well for hoisting the spinnaker, keeps the forward crew in the cockpit to help gather the spinnaker and makes shorthanded sailing much easier.

Tuning the Rig

Before Stepping the Mast Headstay Length. The headstay length is measured from the center of the pins at the hounds to the stem fitting and should equal 32' 9 1/2". The standard headstay is often too short, so you may need to add toggles to the bottom of the headstay under the roller furling fittings.

Backstay Length. By lengthening your headstay, your backstay may become too long. Have your local rigger shorten your backstay wire that runs from above the backstay bridle to the mast crane so it measures 28' 6¾". Each backstay leg should measure 8' 9 3/8".

After Stepping the Mast
Mast Butt Placement. The base of the mast should be positioned 8. 1/2-9" forward of the main bulkhead. Measure from the back surface of the mast to the leading surface of the bulkhead. The placement is correct when the headstay is taught and the mast is touching the aft edge of the mast collar at the deck level. Once the mast butt is in position, tighten it down to secure it.

Mast Blocks. The mast blocks secure the mast in the partners (collar) at the deck level and should be carved to match the curve of the mast in the front and the back. The side of the mast should be secured with rubber inserts cut from the original mast shim. The purpose of the mast blocks is to wedge the mast in place and keep it from moving side-to-side.

Fine Tuning the Rig
1. With slack lowers and slack intermediates, tighten the upper shrouds hand tight so that they are both snug while keeping the mainsail track straight when you sight up it from the gooseneck. Cleat the main halyard so the shackle touches the rail at the chainplates on one side using a light pull. Measure the same spot on the other side of the boat. If the mast is in column, the shackle will touch in the same place. If not, adjust the uppers until it touches in the same place.

2. Now that the mast is in column, pull on the backstay as hard as you can. This should bend the rig and loosen the upper shrouds. Now tighten the uppers again so the new slack is taken out. Be sure to tighten the same number of turns on either side. Now you may loosen the backstay. The result will be approximately 780 lbs. of tension or 32 on the Loos Gauge.

3. Again, sighting up the mainsail track to keep the rig straight, tighten the lower shrouds, with equal turns on either side, to 22 on the Loos Gauge. Given this tension, the result should be I.5" of prebend. Now tighten the intermediate shrouds with equal turns on either side to get a tension of 18 on the Loos Gauge. Check the rig for overall straightness, both at the dock and again while sailing, by sighting up the mainsail track. Adjust the shrouds appropriately to get the mast straight.

On the Water in Changing Breezes
Your mast tuning is now complete for 8-15 knots. When sailing in less breeze, you should take off about three full turns on the lower shrouds and take out the forward mast block. This will increase the prebend in the mast, give you a softer headstay, and give you the optimum sail shape for light air. See our Tuning Matrix at the end of this guide for detailed shroud tension instructions.

Sail Trim

Upwind Mainsail Trim
These are basic tips for trimming the J 80 main which will help you establish a go-fast position for your own preferences in trim.

TWIST IS FAST. By twist, we mean that it is necessary to open up the top of the leech and maintain flow over the top of the sail. A good rule of thumb is to trim until the top leech telltale is just stalling and then ease out 2-3" inches of sheet so that the telltale is flowing again. This is unlike many other one-designs that like to have the top batten parallel to the boom in most conditions. In order to keep the sail powered up and the boat pointing with so much twist, it is necessary to pull the traveler farther to windward than you may expect. Quite often, the boom is 15-20" above centerline.

As the breeze builds, you need to maintain a balanced helm. Begin by pulling on the backstay to flatten the top of the main. Drop the traveler down in increments of 6" for every 3 knots of breeze above 10 knots. As you drop the traveler, you need to pull more mainsheet to tighten the leech and maintain pointing ability. In a big breeze, the top of the main is twisted off and the bottom 1/3 of the main is doing most of the work.

Jib Sheet
The jib shape is achieved by three controls; jib sheet tension, jib car placement and jib halyard control. The sheet tension has the most obvious effect. The jib sheet controls the leech twist and how far the sail is pulled in. If you look at the overall sail as it relates to the sheet, it does two things. Picture the boat on a close-hauled course with the jib luffing as you pull in the sheet. First, the angle of the sail changes, then as the last few inches are tensioned the leech gets tighter. In short, it pulls it in and then it pulls it down.

It is important to try to match the leech profile of the jib to the profile of the lee side of the main. Try to envision how the sails would look from a motorboat trailing behind you.

The jib car controls how flat or round the jib is in the lower section of the sail and the amount of leech tension in the jib. The farther aft the car is on the track, the flatter the bottom third of the sail is and the less leech tension you have. Conversely, the farther forward the car the more round the foot and the tighter the leech. When the lead is at its maximum desired aft position, the foot of the jib will crease as the middle batten comes parallel with the centerline of the boat. In short, a rounder shape delivers more power, a flatter shape delivers more speed. In flat water, you want a flat sail. In bumpy water you want a full or rounder sail.

The jib halyard tension subtly changes the draft characteristics of the sail. As the halyard is pulled tighter, the draft of the jib moves forward and as the halyard is eased the draft moves aft. In lighter air, the halyard tension should be loose enough so that there is a hint of wrinkling in the luff of the sail. As the breeze builds, the halyard must be pulled on harder to eliminate those wrinkles, but not so much that you over stretch the material.

Crew Position
When sailing upwind in most conditions, the skipper should be straddling the traveler bar. In lighter breeze, move up in front of the traveler. The crew should hike out in between the two aft stanchions. In light air, the forward crew should move forward, even with the cabin top.

Downwind Mainsail Trim
Be sure to power-up the mainsail when sailing downwind. Ease off the cunningham, outhaul and backstay. Adjust the vang so the top batten is parallel to the boom or just slightly open. Be sure not to hook the battens to windward with a lot of vang tension.

Spinnaker Setup
When setting up the spinnaker gear, be sure that the tack line goes over the lazy sheet (the sheet going to the opposite side of the boat). This ensures that the spinnaker will jibe to the inside, between the headstay and the luff of the spinnaker, as opposed to around the outside of the luff of the spinnaker and in front of the boat.

Spinnaker Trim
Like all spinnakers, the spinnaker sheet should be eased until the luff carries a slight curl. The real trick to flying the sail and having the best downwind performance, is to maintain constant dialogue between the skipper and trimmer. Together, they keep pressure in the sail without sailing too high and loosing VMG (velocity made good to the mark). As a general rule, the boat sails downwind at 135 degrees to the true wind, jibing through 90 degrees. As the breeze builds, it is possible to sail deeper angles while maintaining good speed. One trick to get down the course fast in a strong breeze is to sail nearly dead downwind with the tack line eased out 12-18". Heel the boat to windward and ease the sheet out. This rotates the chute out from behind the main's windshadow, exposing maximum sail area to clear air. Experiment with this a bit and you will quickly get the feel for how low you can go without stalling the chute behind the main.

Wing-and-Wing
Occasionally, there are tactical advantages to pulling the wing-and-wing trick out of the bag. In breezes of over 13-15 knots, it is possible to bear off to dead downwind, heel the boat to windward and flip the main to the other side. The trick to making this work is heeling the boat to windward and keeping it from rocking and rolling. As soon as the spinnaker starts to look unstable and might collapse, quickly flip the main back over and head up onto a normal jibing angle. When things settle down, flip back to the wing-on-wing, and get going downwind again. The time to use this is when you are looking to make the leeward mark and can gain by not throwing in two jibes.

It is important that you recognize that wing-in-wing is less stable than sailing jibing angles. It can not be used when the boat is rocking and rolling. If you get the crew to move their weight around to keep the boat from rolling to leeward, the time spent on the wing can be longer. Practice this and let us know what you think. It will definitely get some wows back at the yacht club bar.

Spinnaker Maneuvers

The J 80 can be handled well around the entire course with a crew of 4. We will detail the maneuvers for all 4 people; helmsman, middle/aft, middle/forward and forward crew members.

The Spinnaker Set
The middle/forward crew presets the pole, pulls the spinnaker out of the companionway and makes sure halyard is in front of spreaders.

The middle/aft crew pre-feeds the tack line and hands the tail to the helmsman for rounding.

The forward crew hoists the halyard at the helmsman's command.

The middle/forward crew feeds out the spinnaker.

The middle/aft crew furls the jib quickly.

The helmsman pulls the tack line the final distance.

Getting the jib furled is the key to a successful, quick set. This allows the spinnaker to have clear air almost immediately. The helmsman must remember not to ease the mainsheet so much as to trap the spinnaker behind the boom and against the spreaders.

Jibing the Spinnaker
Jibing an asymmetrical spinnaker is very different than most people expect. Shore Sails has developed a small-boat technique that makes turning the J 80 a bit easier and results in a successful jibe without wrapping the sail.

You need a trimmer who is excitable and aggressive and wants to pull harder than a horse during each jibe. This helps to get the sail around the forestay in a hurry. The speed of the trimmer is very important!

1. Get every body ready and make sure that the old spinnaker sheet is free to run. Pull all the slack out of the tack line.

2. The helmsman, or another crewmember, takes the old sheet. As the boat is slowly turned dead downwind, the sheet is eased to maintain proper trim. We have the helmsman ease the sheet because they have a better feel for how the boat is turning through the jibe. Once the clew is near the head stay, the trimmer pulls on the new sheet and the forward/middle crew overhauls the new sheet directly from the clew of the sail (on the windward side of the boat). It helps to have a mark on the spinnaker sheet at the point where the clew is forward of the headstay.

3. Once the sail clears the headstay and begins to fill on the new jibe the helmsman and the forward person must work together to pull the boom across onto the new jibe. The skipper turns the boat up onto the new course. The trimmer eases the sheet out to its proper trim for the new course. Quite often this is an ease of up to 6 feet of line. It is important to anticipate the boat loading up on the new jibe. You need to have the crew ready to move to windward to flatten the boat to accelerate out of the jibe.

Spinnaker Takedowns
Takedowns with asymmetrical spinnakers are tricky maneuvers. We always takedown on the port side on a normal windward/leeward or triangle race course unless a jibe-set is guaranteed at the next windward mark. There are three basic types of drops that should handle any approach to the leeward mark; the windward drop, the leeward drop and the Mexican drop.

Windward Drop
As you approach the leeward mark, make sure the halyard is ready to run and unfurl the jib. Make your approach to the mark a little high so you can bear off downwind to relieve some of the pressure on the spinnaker. When ready, the middle/forward crew hauls the spinnaker around the headstay with the lazy sheet. Once you have the sail in hand, the forward crew eases the tack line to gather the foot of the sail. Be sure to keep the foot tight and on the deck so the sail stays out of the water. The halyard should be blown as soon as the foot is out of danger. You don't want to go shrimping! Retract the pole, clean up and have a great rounding.

Leeward Drop
As you approach the mark, be sure the halyard and the tack line are free to run. You have two options for the leeward drop.

Tack Blow-Away. Have the forward/middle crew grab the spinnaker sheet. When they are ready, blow the tack line and begin to gather the sail. Release the halyard when the foot is nearly all gathered and the sail is under control. Retract the pole, clean up and have a great rounding.

Floater Drop. Over trim the sail so the foot is stretched tight. Have the forward/middle crew grab the spinnaker sheet. When they are ready, blow the halyard. Quickly gather the sail along leech with the foot tight. Do NOT release the pole until the sail is under control in the boat. Ease the pole and the tack line to complete the take down. Clean up the cockpit and have a great rounding.

Mexican Drop
From America's Cup fame comes the Mexican drop, a simultaneous jibe/douse. As you approach the leeward mark on starboard tack, you will need to jibe to round to port. Be sure the halyard is free to run and the jib unfurled. Just before the jibe, over trim the spinnaker to tighten the foot. Have the forward/middle crew grab the spinnaker sheet close to the clew of the chute. As the helmsman jibes the boat, the crew should begin pulling in the sail, making sure the foot gets on the deck and not in the water. Proceed with the takedown just like a windward takedown.

As in all maneuvers, practice makes perfect.

Best of luck with your J 80. The best way to get up to speed is to go out and work through some tacks, jibes, sets and takedowns. Have fun with one of the best sport boats around. If you have any questions on tuning or sailing the J 80, please call us at Shore Sails. We will be pleased to talk to you about your experiences.

J 80 TUNING MATRIX-UPWIND

wind	boom	main sheet/ top batten	main cunningham	backstay	jib halyard/ jib lead
0-6	on center	5 degrees open	wrinkles in luff	loose	1 hole forward of chainplate
7-10	0-3" off center	parallel to boom	80% wrinkles removed	snug	even with chainplate
11-14	6-12" off center	open 5 degrees	80% wrinkles removed	eliminate most backwind	1 hole aft of chainplate
15+	off corner of transom	open 5-10 degrees	smooth luff	very tight	2 holes aft of chainplate

Note: Increased wave conditions may warrant a more open sail plan attack. 

Contact: Doug Shore, Shore Sail Rhode Island  or Bill Shore, Shore Sails International