Friday, February 08, 2013
Hyde's have now conducted 4 separate two boat tuning sessions
at Rutland and Hamble to test their sail development programme on the
water. The tests have mainly been conducted with Nigel Grogan and
Malcolm Hutchings. The testing sessions have covered most wind strengths
and have involved assessments upwind and down including swapping boats
and helmsmen, so we feel that we are really in a strong position to make
valid and scientific observations on Squib set up, tuning and of
course, sails.However,as Mike Lennon , Hyde Sails technical director
explained at the recent SCYC Masterclass, the development can end in a
loop following two boat tuning with no guarantee that each succeeding
sail design is faster than the previous one........
Happily last years results seem to suggest that the Hyde Squib sails are getting faster and faster....although further development is planned!
We have now ( since 2008 ) worked our way through about 8 jib designs , 4 mainsail designs and 3 horizontal cut spinnaker designs.
The main changes, tips and observations are as follows;
The sail is much flatter than the pre-2008 sail. The maximum camber is quite forward when the mast is straight leaving a very straight exit. This makes the sail very user friendly but needs some mast bend in light airs ( but do not over tighten the leech)
For maximimum speed we have found that the foot should be pulled tight in all conditions, except it may pay to ease the foot very slightly in medium conditions ( 8-15knots) off the start line where the increased leech return can add height. For strong winds the outhaul should be pulled on very tight. For light conditions there should be a crease along the foot. The outhaul must be released when reaching or broad reaching. It makes little difference on the run.This is quite important on championship courses to ensure good speed away from the windward mark on the first reach. So much so that on Nigel's boat the outhaul is led back so that the helm can ease the outhaul while the crew is setting the pole and he can pull it on when the crew is dropping the spinnaker. For light conditions the boom should not be on the centre line, the traveller should be pulled all the way up but the boom should be a few inches off centre unless the water is flat and the breeze steady enough for very accurate steering. A flat twisted sail just off the centreline is the goal. Use the leech tell tales to determine twist, but overdoing the twist looses power. For medium conditions the traveller is dropped to around the seat edge, vang is used according to the conditions, but much more aggressively than with previous Hyde sails. Keeping the boat at 5% of heel is optimum ...which means balancing with weight not easing sheet or heeling or luffing. Mainsheet ease through bad waves to accelerate is good. For strong winds, the rig has to be raked back ( and any of the popular ways of doing this work, but the most simple is to have the mast in the middle of the gate and move the caps down 2-3 holes, then adjust the lowers proportionately) The traveller should be in the centreline ( not dropped down to leeward) and the sheet tension needs to be progressively harder almost to the point it cannot be pulled on any more! Boats with the mainsheet blocks on the traveller, as opposed to fitted behind, will have difficulty getting the necessary tension as they pull the traveller car up the track more when really heaving. In 25knots the mainsheet tension should be really tight. The goal is a flat sail that is easily dumped. Hiking hardest is fastest, but concentration should be on steering, especially in gusts and waves to feather before the boat heels and regain pace when the gust or wave has passed. Steering and sail shape is more important than hiking! The optimum VMG will depend on righting moment ( how heavy you are times how hard you hike) but as a general rule low and fast is better in waves and high and pinching better in flat water.
The cunningham is only used when starting to become overpowered. But then it must be used aggressively and must be capable of being eased in any lulls. On 105 this is led to the side decks for the helm to use in conjunction with a shock cord luff so that the sail goes up the track on its own when eased.
The vang is progressively tightened to blade out the mainsail up to the point that the boat is overpowered. Above this level ( c 25knots) it will be necessary to ease the sheet in the gusts as well as feathering to windward. At this point you should be "vang sheeting" so the boom must not rise much when the boom is dropped. However too much vang and the mast will invert and the sail will flog, which is really slow. Using the Superspar mast the point this happens can be delayed by increasing the rig tension and ensuring that the caps are not so loose that the top of the mast bends to leeward and the middle to windward. The vang needs to be extremely powerful and led to the side decks so that it can be adjusted constantly at venues like Rutland. It also needs to be dumped from a fully hiked position when overpowered on a three sail reach. For close two sail reaching it needs to be pulled on to power up the mainsail leech in conjunction with the eased outhaul.
The backstay can be used in very light winds to open the upper leech and maintain flow, but only below 5 knots. It can be used very sparingly when really windy but it is easy to invert the mast with It. It must be fully eased downwind to ensure the mast tip goes forward far enough . On an overpowered reach the backstay can be tensioned to stop the whole rig panting and the jib becoming fuller.
It has been suggested that the lowers are unimportant on a Squib.Our tuning sessions suggest otherwise. If they are overtight they will inhibit the mast bending in the middle and keep the sail too full at 1/3 height choking the slot. They will also cause the mast to bend to windward in the middle which is very slow. In very string winds the combination of slack caps, lots of vang and lowers that are too tight will break your mast! However in certain conditions, medium to strong,it can help to have something to "sheet against" to power up the main, particularly in gusty conditions, where a combination of vang sheeting and a centred traveller seems very quick. The aim is a flat easily trimmed main that is low drag and "solid" in the gusts, so gusts are counteracted by rapid hiking and quick eases of the main.
We have experimented with shock cord luff and foot ropes so that
gear changing can be accomplished quickly, particularly in variable
conditions. We have also experimented with different window positions (
an experiment which ended expensively for Nigel at the Plymouth
nationals!) We have also tried different versions to accommodate crew
weights above what we consider to be the optimum of around 24 stone.
Some of our other experiments have involved wavy leech tape to minimise leech stretch and flutter and other reinforcement areas. The changes that work we incorporate in our standard sails as a matter of routine.
The current production version is similar to the 2009 version. The sail has a leech line to extend life, but care must be taken not to let it become tight ( it will shrink!) or the leech will hook. Only pull it on when the sail is starting to flap a lot..ie when it is past it's best. Some round has also been added to the back third to try to stop leech flap. We have produced a sail with a straighter exit, but it was a bit of a one regatta wonder ( although very fast) The sail works well with either the traditional barber hauler position ( high on the cuddy, a few centimetres forward of the deck edge) or also with the "new" barber hauler position popular in Burnham with the barber hauler exit lower on the cuddy ( see the full tuning guide below) We have experimented with trying to extend the life of the sail and reduce leech flap by gluing the seams at the back of the sail with epoxy as well as reinforcing the seams and adding flutter patches. The goal is to have as straight an exit as possible for the back third of the sail all the way up. This means that the sail is built to incorporate a certain amount of twist when set correctly
In our two boat tuning session the main difference between the two styles is that the "old" set up is a bit quicker in a breeze and the "new" set up faster in medium conditions ( up to overpowered) and easier to get right.
Mike Budd and Nigel Grogan use the "old " set up ( Mike was second at the Nationals. Nigel was 3rd at the Nationals and the Inlands) Malcolm Hutchings uses the new set up, as does Micky Wright, Malcolm was 5th at the Nationals and Micky was 2nd at the Inlands)
The objective of both set ups and the sail design is to get the leech profile to match the mainsail with a parallel slot the whole way up. The leech should exit along the centreline with all the tell tales lifting at the same time ( indicating the correct twist) Also to generate the right amount of power versus height and to be adjustable for varying conditions.
Look up the slot from leeward and ask yourself;
1/ Are the tell tails lifting at the same time.
2/ Is the leech parallel to the centreline of the boat all the way up.
3/ Hike normally and ask yourself if you can handle more power or are you overpowered? If you are then change your settings to those for the right wind range and go through steps 1 and 2 again. ( it's obviously difficult to check the jib leech if its really windy..who wants to sit down there!?..but most Squibs sail along with the sail too twisted, the barber haulers are too tight with the bottom of the sail causing drag and the top spilling wind....look at some photos of your boat sailing as an alternative!)
Then sail the boat next to someone else of similar ability and pace and get the crew to see if;
1/ You are going higher but slower; You need to increase pace.
2/ You are going lower but faster; You need to increase height.
3/ You are going higher and faster; note your settings and go to them off the start line...you're gonna win!
You need to do this on both tacks and ensure the test boat is trying as hard as you. It pays to buddy up with someone to make this a regular pre-start routine. Ensure that the boats are equal ( equal vintage, weight and the crew weight are similar otherwise the exercise is much less effective) Also make sure that you line up on both tacks and both to windward and to leeward of your buddy if time permits. Once lined up make sure that you are about two boat lengths apart with the leeward boat just bow forward and accelerate at the same speed. Do not attempt to squeeze the windward boat out or roll the leeward boat- sail in what you consider your "best mode" for the conditions. You should be able to discern an advantage within a couple of minutes.
The length of the barber haulers from the centreline alters the sheeting angle and because of the rules that only allow the barber haulers to operate in one plane, they also tend to rise when the sheet is eased, so getting the correct leech profile is a function of several factors. The "new" barber hauler position , to an extent, automates these factors. If you want to go into high mode, you sheet hard. If you want to foot, you ease the sheet. This makes this set up a really good one to copy and provided your rake , forestay length and luff tension are correct ( see guide) will give you guaranteed good speed with the current Hyde Sails.
The forestay tension is a crucial control for both set ups. It is possible to use the jib luff tension to make the forestay redundant, but by doing this there will be times when the jib luff is too tight. The jib luff is cut to allow for a certain "sag allowance" and if the luff is tight the sail will be too flat ( high pointing, poor speed and acceleration, feeling underpowered). This can be used to advantage when windy (provided the rig is not pulled forward and rake reduced)
Mike Budd tends to disregard the forestay completely, using jib luff tension as an independent control and unhanking his jib in very light conditions ( which will have the effect of making the jib more rounded at the back generating more power)
Malcolm and Micky use more rig tension than has been popular and with the new barber hauler position have great speed in all conditions and adjust rake by moving the foot position of the mast as well as the caps.
Nigel uses relatively slack rigging and keeps the jib luff slightly tighter than the forestay.
Whichever set up you adopt the key is to go through the steps above to ensure that the slot is even the sail is twisting correctly and the leech is parallel to the centreline.
What is worth noting is that in our two boat tuning sessions almost identical speeds can be obtained with different set ups provided that the sails are set properly for the conditions. The point is to get the jib shape right with the control method you chose , therefore looking at the rig and understanding the differences that rake, luff tension, sheeting angle and sheet tension is what matters.
Sailing across Rutland from bank to bank for hours there were few occasions where the difference in speed made more than a boat length of difference in our tuning sessions; provided both boats were set up correctly.