Pointing to Problems With Pointing

There is one common topic which the followers down the fleet will most often bemoan. Pointing a sailing boat, or rather not being able to point as high as others. In handicap fleets it can get outright nasty this pointing at problems as if they were purely down to fortuiry of boat design and how much lard one helm attracts as his rail ballast.        

                                       In one design fleets it tends to be an issue for all and sundry, especially on the start line or coming off the leeward mark to the subsequent beat. Why  do you not get your boat sailing as high on the wind as a competitor?                                            
           We can divide the answer or rather ‘point you in the right directions’ to coin a pun, into several routes to understanding a shortcoming. Firstly there is rig set up and then there is boat trim and sheeting, finally there is technique. I will touch very briefly on the alternative mentioned above, that some boats do indeed point very much higher by virtue of design.                  

          All boats have a pivot point when their wetted areas are fully immersed to their maximum for each point of sail. In keel boats we find that on the beat, the heeled boat usually has a longer water line and the centre of longditundinal resistance or pivot point moves a little forward. Usually this point on the beat is somewhere between the base of the mast and the trailing tip of the keel. In some boats like the j24, it probably moves too far aft, because the keel is too far back in the design, but because this is quite a high pointing racing boat often sailed in OD fleets, no one really cared that much!

 A boat whose pivot point moves forward will tend to be pushed more by the leverage power of the mainsail along the boom and through the mast. In many 1960 and 70 RORC ‘ton’ designs the boats were built to fit the rule with a large genoa and a relatively small main, and many designs followed this, for example the Contessa 32 and her sister designs. The big genoa becomes an awkward factor as it reaches beyond its optimal wind and starts to fight with the optimal centre of resistance while also heeling the boat and making the waterline even longer and thus more prone to weather helm. This can be very pronounced with over canvassed ton designs fighting themselves out of the ‘groove’ upwind in a cycle of CLR displacement and rounding upon heeling. The answer is to strip down sail early so as to avoid this in gusts, because you cannot depower a genoa very much at all underway.                                          

        Here then we go right out of boat design and into what you do with the boat and how you react to different conditions of both wind and it has to be raised now, sea.  Lets face it, most boat designers know what they are up to and have to comply to safety rules and guidelines when developing a new boat. Ton designs and their Sadler and  David Thomas deriviatives do screw up into the wind when overpowered, but on the beat that is a bit of a safety factor. Impalas were known to tack themselves though after an upwind ‘broach’ so they had to have extra weight on the end of their keels. Even in this example, David Thomas had probably intended that folk should be on a number three and a reef, when in fact they were sailing with full sail in 20 knts wind. Modern designs with rounded hulls and ‘spade’ or bulb  keels and wide transoms tend to hold their waterline better upwind so within reason they are easier to sail however the high volume, flat stern can promote broaching in a boat which is overcanvassed on any point of sail. So correct canvassing is the first step in ‘getting into the groove’ and staying there.               

                       Then we come to rig tune. We happened upon a similar effect with poor pointing on our first trip out in the Melges this year in fact, just last week, and that is what inspired me to write tonight. Way back when about 1998 I sailed a Cumbraes regatta on the very tasty detuned Figaro I, T’jig II owned by the Dryborough brothers. This was a machine with planing potential under its mast head spinnaker,. but on the second start I think it was, we just could not point and ended  up sitting ducks squeezed in by the fleet near the IDM end. We actually won a subsequent race and the overall result gave us a class win or a second place, we collected silverware. They said then the boat just did not really point but in fact later on they had the rig tuned, quite possibly professionally, and the boat could point a lot better. What their issue quite likely was, and very likely what our issue was last wednesday was forestay length and tension.          

   The forestay is really a key measurement on any  standard, bermudan rigged sailing vessel. It controls the mast rake first and foremost, and then how much sag and power there is in the genoa or jib. Too long and you will find the boat develops lee helm, because the mast is going backwards too far and the mainn sails centre of effort goes back, pushing the boat round its pivot point to windward. Very often too long will also mean you are breaking a class measurement or agreed IRC one.  Too short and you will pull the mast too far forward and the boat will loose some ability to point as the centre of effort of the mainsail moves forward. This is a big deal even over the course of two inches on the Melges for example, because it can move the centre of effort far more than just a couple of inches. It messes up the balance. 

However  it is not as simple as that. In a boat like the M24 with swept back spreaders, the cap shrouds are also a major control over rake as they sweep the mast backwards with them as tension is applied through their bottle screws. The mast step limits the amount the mast can pivot as does the maxium bend and compression. Now as the cap shrouds come on even harder the mast compresses and bows forward. We can take some of that out with the inner lower diagonal shrouds,. but not all of it when we are set for mid to heavy weather. Then the forestay is suddenly lieing on a chord now to fixture point which has become shorter, hence the forestay and sail can sag in a leeward curve when close hauled. The net effect is that you cannot actually point as high, because the jib is powering the boat a lot up wind in 12 knots plus with the main being depowered after about 14 knts wind. Your telltales fly early. Now you can on our M24 adjust the forestay on a bottle screw down under the mast, because  it is lead over an axel or wheel in the mast and down to the keel of the boat. This means you can take out this sag and obtain optimal rake. In theory,. However this gets complicated and it is easy to end up either with an out of class illegal mast head to transom measurement, or a mainsail which is hard to trim correctly, or both of course. So later boats were fitted with a fixed legnth forestay, meaning you adjust only the shrouds and you maintain a good balance as the wind builds, while also keeping within your class rules measurement mast top to transom.

                  In many boats though, you can though experiment with legnthening the forestay by a few inches on the bottle screw or pin and rack adjuster. You want to maintain enough tread to have good holding on a bottle screw it has to be said!! 

As in the Melges example, you will need in fact to adjust your shrouds as well because their tension will be altered by slackening the forestay and you want to maintain a tight forestay for poinint high. Your mainsail should still be easy to trim and not start maxing out in how far you can practically sheet in before it or the boom interfere with things, nor do you want too much weather helm. Note your settings in terms of thread screws left on the bottle screws or pin positions on the racks for both forestay and shrouds, and if the backstay has a wheel note there too, or even mark the point at which you tighten it with the rope purchase system if that is fitted. If it is a bad setting with weather helm, note it all the same so that you avoid that failed experiment again.     An example of a boat where experiment showed that an extreme mast rake was best for pointing is the Soling, where the boom meets the deck, very unusual for a boat with a jib and a mainsail and relating to the overall design of the keel and balance of the sails.         
   Getting this rake and sag balance  right before a race or fast passage in a known forecast is just as important for optimal performance as the better known final wee few inches in on the sheets when you want to point high as possible. In some boats you can get away with an average to soft rig setting, and then let the sheeting,kicker, jib track, halyards and cunningham. The modest little Farr Platu 25 could  be sailed like this, using the back stay to first stabilise the rig by tigthening the forestay, and thus achieving good pointing, like a runner in effect, before it and the kicker could be used to depower the sail in the gusts by bending the mast quickly. However given a more definiative blowy forecast, it was better to set things harder on, and reduce rake.              
            The Platu is a good place to move on from righ tuning for rake and discuss balance from sheeting the sails in order to achieve good pointing. Due to a very shord chord keel (fore aft distance) the boat pivots very easily so like in a sailing dinghy, you notice any imbalance between main and jib more than on a spade or long keel.  Too much weather helm and you need to sheet in on the jib a little if you can, or drop the main down the traveller. The Platu can though develop mild lee helm too, when the jib is oversheeted, which is destructive to pointing. Here more main should usually be applied, or the jib sheeted out or opened at the top by moving the cars back and the barber haulers out. A good balance and correct slot angle is key to not only helping pointing by controlling pivoting once the rig is tuned for the race from the above rake techniques, but also main and jib is 2+2=5 . It is more than the sum of its sail area and power alone due to various effects beyond the scope of this essay, just trust me! This nice amount of power leads to speed and that is the next point to raise.                      
             You will hear it said at some point from knowledgeable  sailors that you need speed before pointing, and in a general, non tactical beat this is absolutely critical indeed. There are two things to not here. We are talking about maximal overall boat speed, and the speed at which the keel and rudder, the foils, ‘fly’. A beneteau 25 Platu as mentioned has a very short chord keel of less than  2 feet, so it  flies ie attaches flow and creates lift, at a very low boat speed. That sounds good, you are resisting leeway very soon and able to sail the boat forward, and take the next piece of advice, work the boat smoothly up to close hauled. The trouble with such a short keel is that it  also shakes off attached flow very easily and has eventually quite a narrow groove when the boat is close hauled ie if you point too high or fall off too abruptly it will loose its ‘bite’ in the water, it will stall due  to turbulance. The converse is true of say sailing a Piper or a Loch Long or a 12mR rater. Here you have a need to get up to a higher speed before your keel is flying, because it is so much longer a chord and arc legnth. However  once  flying the flow remains attached as you manoevre up and down from optimal close hauled. In either case below foil flying speed or if the keel or rudder is stalled due  to abrupt movement, you will drift sideways, even if your bow points up towards the wind  more – you will pivot but not gain forward travel.          
           In modern short chord keels though, the flow detaches quickly in abrupt movement of the helm or boat, but reattaches very quickly, whereas if you do shake the flow off a long keel boat, it can take time for it to reattach and you are left with not only leeway, but an ineffective  rudder.      
            Given this foil fly speed and time to reattach if stalled too high on the wind or by abrupt rotational movement in heeling or pivoting towards or away from the wind direction, you can do some simple calculations to build  confidence that you have the keel flying and can  work the boat up to close hauled  in a smooth fashion, maintaining that attached flow and keeping above speed X ie the foil fly speed.                                 Now we can talk about the final luff to close  hauled and sailing the boat  ‘in the groove’. After we get the boat moving on say a beam reach, we understand from the log or the feel that the keel is  flying and the  rudder is  nice and responsive. Then we can work the tiller and sheet the sails in a smooth fashion such that we come up on the wind. *(alternatively you may want to stall the boat to buy time in approaching a start line by abruptly screwing up towards the eye of the wind and thus stalling forward progress)  Your foils are flying but you have now hull speed to think about. This can be roughly calculated by a long standing equation  based on the square root of the water line length but very often there are a sett of ‘target’ polar diagram or table figures available  for popular racing boats. Here we see what boat speed is ptimal for a given wind speed. So when you are close hauled in a modern 35 foot regatta machine your figure maybe between 6.9 and 7.9 knots. In most boats going slower than this is a sign that you are actually sailing too high from optimal close hauled, or of course your boat is not trimmed or rig tuned quite right. In small fast sports boats and dinghies you can actually start to sail a little quicker than hull speed as your boat is light enough to climb its own bow wave in a very early planing mode, even on the beat. However this is actually a sign that you are pointing too low to achieve optimal upwind velocity made good  -VMG , how beneficial the zig zag angle is relative to the  progress right into the  wind direction – until in a dinghy you can actually plane  upwind. The tell tale sign on this is that your stern wave detaches from the aft quarter of your boat. If you point a little higher, you can often see that it reattaches to the hull, and the bow and stern wave stream off in at a parallell angle.These boats tend to be best sailed with a neutral helm ie no weather and no lee, little pressure, just flow over the  rudder and adjustments made by steering to keep the  angle to the wind optimal. Hence this is one way of keeping a boat in the groove if it is a light weight performer.    
    Many of the ton designs and their deriviative mass produced boats have a very prominent weather helm when they are in the groove, this showing that the powerbalance is keeping the boat driving up to wind, and that the lift created  on the rudder itself is helping coutner act leeway. A major element of being in the groove  on what ever boat  is that in fact the boat feels quite settled, still and sometimes it feels slow because it ceases to accelerate and deccerleate. Very often experienced helms rely on the heel and the sensation of water past the leeward gunwhale more than their log and polar diagram as a good  handle as to them being in the groove. Being out of the groove or not maintaining it is the opposite. The boat heels too much, the helm gets imbalanced and loads up or loses influence, the speed is up and down.                 
       So we have learned so far that we need to get the rig set for the expected conditions, we need to balance our sail sheeting, we need to get our foils flying and we want to feel we are in the groove. Now  we are pointing. However we have  those  variable conditions to consider, with the wind being a fickle mistress and waves hindering peachy progress on the beat. Here we come to how we also trim the boat fore aft, to help maintain hull immersion and thus waterline related optimal speed while reducing drag from impact and exit of waves we sail against.
 As the wind builds too we need to discuss a sail change or reef, or try and use the running rigging to depower or power up. In rougher seas with nasty chop many light boats start to be a handful to keep in a high groove and tend to stall up. We need to foot off and steer around the waves, but this also means we never quite sail in the groove – our optimal VMG theory is out the window and we have to sail actively on helm and mainsheet to stop the waves hindering our progress and knocking our keel flow off.  Other heavier boats thrive as the wind builds and once fully powered up can even be pinched up on the wind to depower while still punching through a heavy chop, for example the Bashford Howison 36 and 40 designs.and many older ton and meter designs.
 So now you start to understand perhaps why old sea dogs and medal winners like Dennis Connor still talk about ‘we learned a lot out there today’ after decades of sailing. 

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