For those 5 or 6 years of "rignorance" I usually left it up to the owners, hardly touched a turnbuckle. On some of the boats I sailed on either had runners or a mid setting on the rig which we could tweak on the running rigging to depower enough. Alernatively just change down head sails and reef. Also I sailed a tasar which has on water rig tune, using sliding shroud bases.
My take on rig tuning is firstly this: YES YES YES, do it!
Secondly consult the class manual and the tuning guide with your sail type, or talk to a sail maker (while pretending to need new sails). Then also get a loos gauge and a camera with the right focal legnth to take images of at least 2/3rds of the height of your sails without too much distortion ( it is relative anyway, if you remember the focal legnth and exposure you use and replicate it each time).
Thirdly- rig tune can be a standard affair like in the Melges 24, but in many boats , above the tuning guide it will also be influenced by
1) the age and therefore stiffness of the boat
2) The exact set of sails
3) Your crew weight and to some extent, skills / willingness to hike hard
4) Your all up expected weight- crew, their bags, their beer etc
Not Caring About Rig Tune
I sailed a sigma 33 which has a bit of a trunk of a mast, most of them stayed up in the 79 Fastnet race. The owners pretty much did it once a year. One keen main trimmer was allowed to adjust the headstay at their own risk. On other sportier boats, as I say the set up responded to sail controls and stripping down early, and we won races on tactical decisions not purely boat speed as these were mostly HC races, with the exception of the wonderful wee 707 and idiot savant I sailed with on the Forth!
In other dinghies as crew I also more or less forgot it until it was blowin a hooly, when I would ask about the rig setting and beef up the shrouds if we could (not easy actually on the RS400 in particular I found in getting it on on both sides)
Gettiing Rid of Rignorance
It wasn't until I started sailing Snipes and sailing with some really clued up guys that it sunk in that Rig was something I HAD to get into if I was to progress my skills and involvement with boats.
Soon I was able to turn up and feel the rig : I did this on a j109 - reporting it soft as hell. It blew 30 knots and i fought a single reefed mainsail like a banshee the whole way round a 15 nm course, my arms almost out their sockets by the end. North's had used the boat in the autumn and the rig had been up (against any better advice) all winter, probably because the boat was for sale. Norths confirmed the setting as "light" !
How to Start Rig Tuning
You will have done your basics right ? Putting the rig up and checking the base plate to mast top is the same on each side using the main halyard ?
Tune on the loos gauge to recommended settings for your average wind- then you won't be too far off any given days wind and you wont have so far up or down to adjust if you remember to leave the boat up at a medium base (as against some sailmakers "BASE" which are given as a start point to tune from sometimes actually below any setting whatsoever) , usually the shrouds are amenable to this, on a smaller boat with hanks or a wrapping luff you want to do the forestay.
At your own locations BASE then, now sight up the mast by putting your head on the boom and lining your eye up the track. Surprised there are some kinks or a bend off to one side? Recheck your loos gauge on all the shrouds, and send a man up the mast if you have bend further up which is being inlfueneced by diagonal uppers (D2) from the spreaders to a higher point on the mast. Get them to double check the shrouds are located in the spreader ends correctly and in the fitting into the mast.
Hopefully now you have a mast in section with the same loos gauge tension on each side, double checking by taking the main halyard over each base plate again.
Now you want to measure the rake and forestay legnth unloaded ie straight. If you can get the loose gauge on the forestay (even re-fitting the tuff luff after) then all the better, but otherwise you want to compare the recommended legnth. Some sailmakers are generous and give this as halyard legnths so that you can hoist a good quality metal tape (does not stretch) up the mast, while others will refer the actual legnth inclusive or exclusive of the turn shackles. In which case you then can just use an accurate halyard hoisting of the tape, tieing it off in a way you note so the measurement has the same datum next time.
Now you can measure the rake more easily by using the main halyard which is usually the sail makers reference, but not always, sometimes it is backstay. It should be mid transom top, but for instance on the Melges it is transom-hull meet which is stupid but maybe allows for some construction alteration in transom height over the years I do not know, it is stupid.
Oh, did I forget to mention that maybe you should measure your forestay and backstay off the water ?? ......and then use the halyard as an index to this before you take any more tension on the forestay ? Yep, good idea, then the halyard measurements are a much easier and therefore better index of what the rig tuning session is doing.
Photography
Taking shots up the slot, the luff of both sails and the main girth of the mainsail is covered elsewhere on the electric internet and in many, many books plus if you have an OD with a good tuning guide from the major sail maker.
The point is to do it all scientifically - that means accurate, noted down and repeatable: crew weight is the same, wind is measurable within 1.5 knts, the helmsman is the same, the running rig is the same and the camera settings (focal length and optimal depth of field / contrast exposure) are the same - and sail with your BASE settings in less and more wind that their target wind. This will then confirm that BASE is approximately right and that stronger wind will sag off your forestay more while light winds will do less, and what happens to the max draft and leeches / twist in both sails.
Then firstly tune on the running rigging more: see what happens in the photos. Perhaps BASE averagewill cover a very broad wind range as I have experienced in many boats , with running rigging flattening and filling the sails enough each way. An uppy-downy wind speed range may be typical at your club on Wednesday nights as the sun lowers, or through a weekend regatta.
Then tune things up: firstly if you note a decent sag at BASE in base conditions, medium wind of say 8 to 10 knots depending on your venue, I would tighten the forestay and sail it on that and see what that does to the foresail, its' exit and then what it does to the main and of course the feel and weather helm on the boat.
I would do this first because using shrouds first may take out sag, but it may flatten the main off too much. In some boats with bed\ndy masts, shrouds may compress the mast enough to even shorten the foretriangle distance and so their sweep may not take up the sag very much at all.
Note what happens to the jib/genoa and you should be able to work out if this is good for more wind or not, before you note the turns / thread left / holes and halyard index legnth for that tighter luff setting.
The reverse is true of the shortened forestay with Rake- it increases the back triangle and brings the mast head forward in the absence of back stay compensation. Here you once again want to look at what the back stay does before touching the shrouds from base.
Since a tighter forestay is desirable for heavier winds, the rake should be reduced from the BASE setting and you should see that the mast bends under increased backstay so that the leech opens.
Sail on this setting with BASE Shrouds
Now you can come to the shrouds : when sailing sight up the mast and take main luff pictures to check for sideways sag in mid mast area or top mast fall-off. Then consider the depth and draft position of the main sail. If you have modern laminate fibre sails then if you flatten the sails down from BASE but in the medium base wind, you can count on just a little more depth when it is blowing on them, not much.
The inners aka lowers, or Diagonal 1 and top Diagnoal 2 as they are known, take out sideways sag in the mast first and then take out a little of the bend depending on where their fastening points are- so they act like a check stay. IMHO on almuminium masts having slack inner shrouds means dubuious sideways movements and fatigue on the rig. Fine for a sub 37 footer on carbon rig but they are going to tire a mast and may affect the tension on the head stay due to this falling off on a fractional rig.
The cap shrouds, aka upper, outers, top shrouds or C1s with swept back spreaders as is the norm now, induce a small amount of rake backwards but more importantly they compress and bow the mast so that the mast bends forward around some mid bow point or in an asymmetrical arc which is more common.
So if you bend in you flatten the main sail, but also you can make a bendy mast sag sideways when loaded up and so you take out with the D1s and higher up in the mast on a twin spreader or multiple spreader rig, the d2s also help shape the main. Depending on the boat type- some D2s can be set on a medium to hard setting and left for the season, other boats depend very much on tuning these, so you need to get a "Monkey" who can climb and work a turn buckle 30 -40 feet above the water !
Luckily if you have a set of written settings and loos gauge numbers, you can tune to this. However this should be a guide, and maybe you lack it: so you can therefore use the theory of bend, luff sag and keepign the mast laterally in column to make your own list of settings and try them out in different winds.
You then come full circle, in this case, as harder than BASE setting which you have now noted on the gauges, the thread turns and the halyard tapes OK? : Now go out and sail and take pictures of the sails, noting wind stregnth, sea state, sail settings on the running rigging and log speed how do the running rigging controls act upon the sails now? Do you get further flattening or deepening or have you maxed out so the kicker and backstay have little effect ? Back to the drawing board ?
This is where two boat tuning or the use of a good GPS comes into play if you want to max an OD in particular or beat your nearest HC boat. I recommend you sail on base first in winds up to "top of 4" and see how you go on the running riggging controls: do you have too much heel and weather helm? does the rig become unstable? What is your boat speed like up and down the wind stregnths from base? If you took out the sag on the forestay, does this make the boat feel good in more wind now ?
Like I said in the j109 we beat a j120 and various other boats, winning class, by working a completely WRONG boat rig set up to its limit, I thought the mast would shake off the boat but jøss, did we have boat speed!!!
Now you get into the finer tuning area once you have more experience with your own boat and crews actual sailing. The main factor is all up weight, but also your prefered helming style and feel in terms of weather helm, acceleration out of maneuvres and up wind helming action in waves versus flat water.
Given you then tweak again, and sometimes like in the J35 or J109 the right setting looks a little kinky on the mast from the side with the sail down, then you have honed down to a list of settings which will also then finally inform your time to reef and put up a smaller head sail, when at say 24 knots in some baots, your rig setting is hard on for more sail and you are using style and running rigging on a hard rig.
Sail Changes and Rig
From above... Other boats will need revised settings, forestay legnth in particular in order to regain the balance in jib power and weather helm, so once again we come back to experience of the settings around those top of full sail, top of number 2 genoa with full main wind speeds that maybe you need a softer setting and an earlier change down in order to have the right gear when you do change down, and not be on the one hand holding big sail area way too long or not being able to use the running rigging to put decent depth and pointing into the sails once you strip down.
Summary of Philosphy and Practice - One Design
At the highest echelons of one design, and in powerful carbon mast boats like the Melges 24 (20 and 32 for that matter) then there are optimum crew weights and therefore optimum rig tensions. You can make an allowance for minor deviations in your crew wieght or upwind style but IF the wind is to be constant then it is pretty much dial-in-those-tensions-and-play.
HOWEVER - if you are a little on the heavy side or light side in a forgiving one design, like the RS400 for example or the Platu, then you can tweak to your own taste.
FURTHERMORE: if the wind forecast is very up and down, then you want to find a mid setting on your boat to which the running rigging can be adjusted - or for example on the Melges 24, use a tighter forestay for the top end and then adjust the shrouds between races. In thoroughbread OD, you can play with a mid or bendier setting ( often where the inner shrouds are left looser than you would otherwise to allow more flexibility in the mast from kicker and backstay) .
Finally you may have a preferred upwind style which pays in the seastate for your relative performance ie you beat OD boats usually around your level with a style you like. For example you may prefer a "sawing" motion through waves which needs a wide entrance on the jib ie knuckle, and draft point forward, or reverse- you may prefer a low, powered up punching style where the boat drives itself more and the helm is more neutralised by using sag and a foresail with draft further back. To optimise these for sailing say in 4 foot nasty chop, in an 25 foot OD you will need to adjust the rig before you can use running rigging to fine tune on the water.
Summary of Philosphy and Practice for HC
As I list off above there are the personal factors which play in here and weight for most cruiser-racers out their in HC land is the most critical to factor in: do you care about stripping the boat out for important races or will you carry what's on board ??
Also as you will gain from above, my own experiences of sailing HC boats is that given any distance to sail through the day, or sailing in the falling sun hours, you really want to look at the range of wind you can utilise the running rigging and making smaller adjustments with the rig settings, taking an average setting for the day or a slightly slacker setting if you know that you can flatten well on your running rigging or take a sail change / reef sooner.
You also therefore want to look at how your reef points and smaller foresails affect the need for tension,: remember that pressure exerted on a sail goes up by the cube as a function of wind stregnth, so 30 knots wind is a heck of a lot more pressure than 20 knts. So if it was blowing 20 and you used a slack inner shroud setting to flatten the main on the kicker, if it kicks up you may need to tighten that or put in a double reef to releive the rig from sideways bend and "bouncing"
If All Else Fails When the Wind Suddenly Blows
On that point of double reefing on a soft inner shroud setting when it blows up unexpectedly, good seamanship oft' ignored by racing fleets is to strip and flatten early because all that is a lot harder if the wind is up than it is to reverse if the wind falls, and this is because of the x cube effect of wind pressure per square meter sail area.
If you know your boat likes a first reef in steady 22 knots, which can be peak 27 knots, then put it in and see in the gusts how overpowered you are, and how little twisting the main off helps.
On the other hand, some people in windy areas develop a fine pinching style on full rigs which they hold in 50% higher wind strengths than visitors in the same boat from average air venues.
However I like good seamanship so I recommend hardening the standing rig settings if you see dark clouds and a falling barometer on the dock, stripping down the foresail early, flattening the main as much as possible and sailing before the race up the beat to see if you need a reef. You can then get a big tactical advantage having sailed up the beat a little before the fleet arrives in good sighting distance of you, by coming back down and at 2 minutes to go, putting in a reef or a sail change before the competition has worked out it might pay, and are locked in a full-sail arms race.
In a dinghy or sportsboat, you may become adept at picking out split ring pins, or turning and counting shroud holes, while some keel boats have different chocks infront of and under the mast to adjust bend and pre-compression, and others have hydraulic forestays, backstays or mast base rams to tension up the rig quickly. So if you see weather signs for more wind or think that the gust range is on the high side then you can hide away somewhere before the 5 minute gun and tweak up the rig to flatten the sails.
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