Mast Tuning Guide

Lido 14

I have been asked by a number of Lido 14 sailors to help tune their masts. This is a guide that will be continually updated and eventually posted on a Lido 14 Fleet 59 web site that I have put together. Key areas that this guide will touch upon are:

1. Diamond stay tension.
2. Mast curve (side to side)
3. Shroud tension.
4. Mast rake.
5. Maintenance

The Diamond stays are the stainless steel rods, which attach just below the hounds and just above the gooseneck. The diamond stays play a critical role in the tuning of the Lido and unfortunately it is a role far too often neglected. The diamond stays on a Lido 14 are what control the side to side flex of the mast when they are tensioned around the spreaders.

When I first begin to rig a mast, I start with the diamond stays. Initially without the stays through the spreaders I sight down the mainsail luff groove (using two sawhorses) to see if the mast has many natural bend port to starboard. I don’t think I have owned a Lido 14 mast that didn’t initially have some sort of bend. Once I attach the spreaders to the mast and then thread the diamond stays through the spreaders I begin to tension the bolts at the end of the spreaders to begin to pull the mast straight. Obviously if the bend is to port then you tension the starboard spreader, and if the bend is to starboard then you should tension the port spreader bolt. Once I have the mast straight I then equally adjust both sides to take any slack out of the diamond stays, however, I never tension the stays to the point where they would play a high note, there is no reason for over tightening the stays.

Once I get the mast into the boat and attach the forestay and the shrouds for their medium air position I take the boat out sailing. Ideally I like to sail the boat in 5 to 8kts to weather. I have my crew drive the boat while I sight up the mast to see exactly how the mast is behaving. In light to medium conditions I like the mast to sag to leeward this sets the main up with a nice full shape which gives me plenty of drive. Think of the bottom end of Huntington Lake, the boats that pull away on the final beat to the finish are rarely the boats with their sails strapped in tight. Even though it is regularly blowing hard in the bottom area of the lake the boat needs every bit of extra drive in high chop situations to keep it from stalling out.

Of course you will have to play with the diamond stays to find the right amount of sag for your sails, and pointing ability.

The shrouds on a Lido 14 are peculiar things. The boat demands that they are loose, which in turn plays havoc with the rig while sailing. The Forestay is what controls the mast rake. Most people sail with a shroud tension of 20’-10" to 21’-2.5". The mast rake seems to fall in the neighborhood of 20’3" to 20’5". Over time, I have developed my own numbers for which I set my rig up with

Light to Medium: Shroud Tension 21’-0. 5" .

Mast Rake: 20’-4"

Medium to Heavy: Shroud Tension 20’-11. 5"

Mast Rake: 20’-4"

*Using Sobstad / Quantum Sails

I also will if the conditions call for a change aggressively re-tune my rig for shroud tension while between races.

Basically the best thing to realize about the shroud tension is to set the shrouds according to the tuning guide that your sailmaker gives you with your sails. To get a quick reference for where your rig is set up you can use the old trick of grabbing the forestay and turning your fist 90°; the forestay should have about 90° of turn to it.

Remember that because the shrouds are so loose it is a key responsibility for the crew to stabalize the rig while in choppy conditions this will help the sails maintain their shape and keep the flow over the sails.

The key to measuring any rig is to be consistent. Use the same places to measure from, and measure with the same tape each time you check your rig. There are some very important things to think about when setting your boat up for racing. First is your mast positioned correctly in the boat fore to aft and side to side? It is important on the Lido that the boat’s mast step is at the furthest aft position allowed within the rules. This aft position of the mast helps to reduce the significant amounts of weather helm, which a Lido 14 can have. While adjusting your mast step, use a string run from the bow to the stern on the exact centerline of the boat (this will aid you in making sure that your mast on the centerline. Next once the mast is up check that the side to side measurement is the same port and starboard. Complete the side to side measurement by having your tape measure pulled to the masthead by the halyard, then run the tape to the through-deck fitting where the shroud goes to the chainplate, pull the shroud to the side of measurement, then measure to the trough deck fitting. If your mast is off on one side and you have your shrouds on the same holes in the chainplates, then your chainplates may be mounted in different locations, or your shrouds could be of different length. Another key area on measuring is with the masthead. If you are still using the old wire to rope masthead style, measurement is simple, pull the halyard (with the tape) all the way up. If you are using the new masthead fitting, then measurement is more complicated. My halyard for my main is 1/8" PBO Vectrus with no shackle (I tie a knot to raise the main) If you are set up like I am, you could actually suck the tape through the masthead. So when you measure with the new masthead it is a measurement of imperfection at first. You must develop a point to which you raise the halyard to then from a distance away from the boat eye the tape and make sure that it is in the same position every time you measure the rig. Unfortunately this is as good as it gets, but once you measure a few times you will develop a feel, and remember the place where the tape is raised to each time (is it the lip of the new masthead or is it just at the top side of the sheave) Remember the shroud tension should be measured to a centerline point on the stern such as the top of the transom. All measurements should be done with little to no wind affecting the rig, and with the boom off of the mast to ensure what I call a "free standing rig."

Remember your mast is aluminum and most of the parts that attach to it are stainless steel. The harder you work at reducing where the diss-similar metals are in contact the longer your mast will stand true. Use silicone between all parts and in every hole drilled in the mast. Where through bolting is necessary such as at the diamond stay attachment points place a rubber or plastic nylon washer against the mast to separate the metals. When riveting parts to the mast such as the gooseneck or cleats try to use Monel rivets, which are strong and have similar properties to aluminum in regards to metal to metal contact.

Every time you sail your boat in saltwater remember to wash the entire mast, and every six months wash the mast to keep a protective coating on it. When the boat is not sailing take your mast down and cover it. When your mast must stay airborne remember to tie a shroud and or the forestay off to keep the mast tensioned up. This reduces the negative affects of ramp launching, trailing the boat with the mast up, and the shaking about which tends to ware on all the attachment points, when the boat is in the water.

I replace my shrouds yearly, however I sail my boat usually three weekends a month and many weekdays in between. If you want to help insure your rig will stay up in the big blow, replace your shrouds at the first sign of any ware, or rust at any of the terminal fittings. The best fitting that I have found is a standard aircraft eye at the chainplates for the shrouds and a ball and fork fitting at the hounds. The ball and fork fitting at the hounds tends to last longer because the ball is able to move within the fork, thus reducing the negative affects of trailer vibration, it also allows for freer movement when the mast is upright.

The Class Association provides a diagram of a Mast Shroud Preventer. I highly suggest that all boats be fitted with this simple piece of rigging. Because the rig is sailed so loose the mast while sailing off the wind can actually flex forward and aft, in a pumping motion, which will eventually lead to a catastrophic failure of the rig. The shroud preventer acts in a similar manner to a big boat’s runner system, where the preventer allows some of the loads to be distributed throughout the entire length of the mast, thus keep the mast straight wile sailing downwind.

Some key things to remember about mast technology. While the mast on a Lido 14 is highly governed it is still a place where much aggressive cleaning house can occur. Save weight, every once up the rig significantly changes the righting moment/ center of effort on a sailboat. The less weight aloft means reduced heel, reduced pitching, and less hiking. While one might think; " there simply isn’t enough rig for weight to make a difference, that only works on big boats" I have this reply; I saved 11.3 lbs. When I shifted to the new halyard fittings, switched to high strength small diameter line halyards, and removed the factory foam from the mast.

Good Luck in your tuning, if you have any questions please do not hesitate to call or email.

Thomas Jenkins