How many of us enjoy being overtaken – especially by a smaller boat? One of the joys of sailing a well set-up Noelex is how you can keep up with or pass much bigger boats. Even dyed-in-the-wool cruising salts can suddenly become racing demons and start tweaking the sheets to avoid being left behind, or to be first to that prime anchorage. Our innate competitive instinct rarely sinks far beneath the surface! Then there’s our curiosity, why are they going faster than we are?
Knowing how to pull our sails into the right shape can make all the difference to our enjoyment on the water. Well-trimmed sails get us home before the pub shuts, the tide turns or the weather gets nasty. A well trimmed craft makes the difference between lurching along on on a bumpy sea with the tiller under our chin and the soup spilled all over the cabin sole, and sailing swiftly and comfortably with dry decks.
Speed and comfort, in fact, often go together – because setting your sails efficiently is all about maximising drive and minimising drag. Racing or cruising, we all want more speed for less heel and less leeway.
However good your sails, they’ll never set as intended unless the rig that supports them is doing its job properly. So the first reuirement for a well trimmed sail is a well tuned rig.
Firstly we need to have some initial tension in the rig to straighten out and eliminate any slop from within the wire and the wire bundling. In addition, the thimbles, shackles and crimp connectors all need tension to get the slop out of these as well.
Over tensioning is bad. You can wear out your rig faster and build up large mast compression forces. You can even do damage to your deck even though on the Noelex there is good support inside the cabin for the deck-stepped mast. In practice though, it is difficult to over-tension a Noelex rig. Under tensioning is also bad, probably worse than over tensioning. If your rig is loose, the mast has a tendency to slop from side-to-side due to being knocked about by wave motion, gusts of wind and any pounding that may occur and so forth.
A loose rig is one in which the lee shroud becomes slack in moderate winds. This allows shock loads to build up and be applied to the rig due to the wave motion etc which could be in excess of the designed loads. This can cause the rig components to weaken and perhaps ultimately break. A loose rig allows the mast to tip to leeward, and the forces generated cause the boat to heel. The weather helm increase and the boat will not point as well as it should.
The initial tension to take the slop out of the shrouds is about 80Kg, but there is more to tuning the rig than just doing this.
Get the mast upright.
The mast must be set vertically for the lateral axis of the boat. To do this make sure the shrouds are equal in length. If not, adjust the rigging screws. You can also check this when the mast is erected by raising the end of a tape measure on a halyard. Or just use the halyard. Measure to each chainplate to check for equal length. A further check can be applied by measuring from that point on the raised halyard to identical places on the left and right of the transom.
Measure the rake from the goosneck
With the masthead now central, sight up the luff groove: laterally, the mast should be straight. If you have any sideways bend, most unlikley, you will need to remove it by reshaping the mast base or use some packing material.
The Rake
It is necessary to set the mast rake aft. That is, the mast must tilt back a bit on the longitudinal axis. To do this with the boat on a trailer it is necessary to set the level of the boat. To a first approximation it is OK to set up the trailer so the waterlines are level. This assumes the boat sits on its lines when in the water. Use builders level or a plastic tube filled with water.
When happy that the lie of the boat on the trailer is the same as that in the water, run up a plumb bob on the main halyard. Measure the distance from the plumb bob to the lower sail band. This distance should be between 70 and 200mm. This gives an angle of between 0.5 and 1.5 degrees. Less rake will induce less weather helm however in heavy winds more rake is desirable.
The trim of the boat in the water is another factor to consider. If the boat is down by the bow the weather helm will be increased due to the Centre of Lateral Resistance (CLR) moving forward, if it is down by the stern the CLR moves back and it will be reduced, eliminated or even have some lee helm. It is best to get the trim correct first and then experiment with the amount of rake for optimum performance.
We need some pre-bend (not this much though!)
You need a bit of pre-bend to suit the cut of your sail. When the mainsail is as flat as it can be, the curve of the luff of the sail must match the mast bend so the two fit snugly together. A mismatch will show up by heavy creasing running from the luff to the clew. Minor short creases along the luff are not so much of a worry; they can be eliminated by the use of the cunningham.
To induce mast bend increase the tension on the shrouds, do each side a bit at a time. Eye off the mast frequently to make sure that the bend is occurring smoothly and with no S bends etc. If the mast is not bending from the tabernacle you may need to shape the front of the mast base to allow for some tilt forward. You may also need to elongate the mast pivot pin holes to allow for the extra movement.
If the mast starts bending sideways you will need to remove material from one side of the mast base to correct it. You could also use some packing material on the other side to achieve the same effect.It is best not to exceed 15% of the breaking load on the shrouds. With the 4mm shrouds on the Noelex this is about 200kg. How do you know if you have enough tension?
If your mast is straight laterally, if it has the correct mast bend, if the lee wires do not go floppy on a close reach in 15-20 knot winds or if you can’t deflect it more than 50 or so mm with your finger when sailing upwind in moderate conditions, it’s not too slack.
Your rig is probably tuned acceptably unless the its over tensioned. To test for over tensioning, pluck on your shroud. You should hear a low note. It is difficult to over-tension the rig on a Noelex due to the limited tension the highfield lever can impart to the forestay. For optimum tension, it may be necessary to increase the tension using an easily adjustable stay tensioning device such as this Ronstan calibrated rigging screw.
The tuning of your rig will have more impact on your speed and handling under sail than anything else except sail trim, yet excellent sail trim won’t compensate for bad rig tune. In fact, you can’t trim your sails in an optimum manner if your rig is not set-up correctly in the first place.
But sail trimming is another story!
Gil Webster