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Sorry I should have made one point clearer; there can be a difference between the % aft of the maximum draft of the batten and the sail. Change the bend shape of the batten to obtain the desired shape of the sail.
A initial approach is to place the battens in without tension, then datum mark. Apply maximum tension, and datum mark. Then apply pressure so you are mid way between the two extremes, this is your starting point for tuning.
If you are a perfectionist, use a small fishing spring weigh scale which will give you are precise tension for future reference I also use the scale for measuring the Euler crippling load which gives an indication of the bendiness of the batten. If you are unaware of the concept; the more pressure you use to bend the batten the more it bends until at a certain pressure it will continue bending with no more effort. A stiff batten will require more pressure to reach this crippling load. Note, it will depend on the length of the batten so each must be tested, the shorter it is the higher is the crippling load for the same batten thickness.
Again, the perfectionist will measure the ECL and point of maximum camber. With a full length batten on a single sail boat the target is 50%, but if you want to point in moderate breezes then 55% aft can work.
However be warned, fiddling with boats is my hobby which is occasionally interupted by actually sailing which I find is more energetic and wet.
The advantage of a rig tension measurement tool is that it helps you repeat the tension that won you the last race, or sneak up to the winning boat and find out her secret.
Regardless of the make, they are all basically a spring which measures the pressure needed to pull the wire out of line. The more rig tension in the wire, the stronger the pressure to obtain the standard distortion. The stronger the wire the more pressure required, this is why the calibration figure differs for the diameter of wire. For example on a Loos model A pulling out to the 32 mark indicates 181 kg in a 2.5 wire, 136 kg in 3.0mm but only 91 kg in 4.0 m wire. That is 1x 19 wire, the equivalent tension in 1×7 dyform wire would be different as it’s a stiffer wire.
In many more complex rigs the sailmaker will give you a crib sheet of major numbers for tensions, rakes and spreader angles. For example I have a 10 page Int. Dragon tuning guide from a sail maker. It certainly helps when they are some 10,000 possible combinations.
The Sabre is extremely simple, and any guitar player can tune one with a MK1 RTG but they may not always be singing your song.
In response to Steve I would like to make a few comments having run numerous national championships; one with 300 plus dinghy starters. In a weekend national with 80 dinghies in several divisions we started 36 heats with people on the committee boat more exausted than the sailors!
It is a major consideration if the class management are trying primarily find a national champion or encourage the greatest number to participate. With the general decline in sailing usually the later takes precedent.
The Gate Start was introduced when there were problems in overcrowding, leading to a number of general recalls; eight at one European Championship each some 15 minutes apart. Under the old standard starting procedure over 10 minutes it was common for the line to be layed 15 minutes in advance not taking account of wind shifts. Another consequence was the introduction of the ‘Black Flag’ rule. Giving the line line port end bias is no solution. I am generally against gate starts as first beat options are limited and it is not necessary except in large fleets of high performance boats. With the modern starting procedure any good RO should be able to reasonably predict wind direction over 4 minutes to give a fair start line balancing bias on the line against the prefered course side. The ideal line is when it’s best to start in the middle! On a minor point the best sailors are not at a disadvantage, the strategy is if you are better than the ‘bunny’ you go early, if slower go late.
Another solution is to spit the fleet, the top boats in each fleet coming together later for gold/silver/bronze fleet competition. Another approach is to time for the first 15 minutes then go up the course allocating positions to speed up race turn round.
Remember the event is for the benefit of the class and its competitors, thus the SI and RO decisions should take that into account. Sometimes the wind conditions are within the class limits but the sea conditions or lack of safety boats are more critical. This is particularily important if the championship is open sea and many competitors usually sail on lake/estuary conditions. One suggestion is a class committee to provide on the spot advice to the RO, this is within the RRS even if they are competing. I fully agree competitors should be advised at all times as to what is happening. While the old fashioned briefing is out unless in the SI, the RO can indicate their intentions at the competitors meetings or on the notice board.
The modern trend is for a large number of short races sailed back to back.
In most conditions you can run four races a day aiming at 30 minute winning time and one hour between starts. It is important to take account of the slower boats, for example at the Mirror nationals it took up to 40% longer for tail enders to complete the course. You have to balance between keeping the leading boats waiting and giving the slow boats time to recover. As Sue said this style of racing requires several drops as broken gear and capsizes are a problem. My preference is only have a time for the first race and the latest time for the last race, everything in between fexible using AP plus H or A.
To sum up, the class management should seek feed back from the nationals then decide on the format which members want and advise the next host club.
Sue,
The term ‘dodge tide’ was invented by Flinders to describe a Gulf condition which is found in only about five places in the world where there is a day of minimal tide.
In simple terms there is a sun tide cycle of 12 hours and a moon tide cycle of 12 hours 25 minutes. Thus, every 14.77 days they tend to cancel each other out resulting in the neap tide with minimal difference between high and low tide. Technically a semi-diurnal tide cycle.
In the case of the Gulf, the land is so shaped as to trap water flowing with the west- east earth rotation ocean tide. The result is that every 14.77 days there is a chance of a ‘dodge tide’ of around .5m rather than a normal 1.5 m at Port Adelaide.
The impact on sailing is that there is limited cold water flowing into the Gulf which vastly reduces sea breeze. The result is lake conditions; flat water and little breeze. Typical ACT afternoon. Very rarely after an Antarctic storm you get long heavy swells and no breeze. The hot air weather condition is a seperate issue which can lead to dust storms in Melbourne and an increase in beer consumption!
So you are right in your understanding of a ‘dodge tide’. However there is still a little bit of current which will float the buoys out to the maximum length of the anchor line.
The only other place in Australia to get ‘dodge tides’ is the Torres Strait. In 1944 an American mathematician was given the job of predicting tides for the US Navy. It so frustrated him he committed suicide. These days with computers it is slightly easier and someone at Adelaide Uni has just finished a PhD thesis on predicting tides in the Gulf. Very interesting mathematically but unfortunately not useful when sailing a Sabre.
Paul
Having run numerous regional and national sailing events round the world I was very interested in the discussion on movement of marks. This has become important with the use of GPS for both course laying and navigation.
Both tidal flow and wave/wind action move the surface location relative to the anchor. Even minor variations of these will move the buoy to the maximum distance away from the anchor vertical location. Tidal range is not a direct factor. The critical question is how much slack to give after the anchor is lowered to the bottom.
If for example the depth is 100m, allowing an extra 5m of line will result in a variation of the buoy position by 60m. Allow 10m of slack and the variation is 90m. In comparison, Australian tidal ranges will have a relatively minimal impact on the variation of the surface position.
Thus, there could have been different variations in the amount the buoys moved during the race depending on both the depth and the slack to depth ratio, not on the tidal range. Remember tidal flow can be strong even when there is no change in tide height. In the Gulf, tidal flow can continue up to an hour after high/low tide [race strategy hint!].
If you think there are problems at Adelaide, think of the problem at places like Hawaaii when depths are in thousands of metres. Apart from problems of an accurate GPS set, cutting the anchor line is a viable option after the race due to the time to retrieve the anchor from the depths.
A buoy is only a mark when it’s on the leg you are racing!
Paul
Barry, I fully agree the mast step positions impact on rake. I moved mine maximum aft to reduce rake simply to give me more headroom on tacking; however could please you expand on what is happening as you tighten your rig?
As I tighten my shrouds the mast bends allowing the mast tip to go aft shortening the black band:transom distance. I have the shroud and forestay attachments maximum tolerance apart to promote bend as most of my sailing is light wind, thus easing the leech. The result is my rake: Loos gauge distances appear to move opposite to your results.
As for optimal rake, I suggest adjusting the shrouds until the boat is balanced with about 2 degrees of helm going to windward. My new Irwin requires one-two shroud holes longer than the old sail to get the same balance due to sail shape differences.
I suggest you look at the topic ‘The history of fibreglass Sabres’ from March 06.
Kim Snowball of SA built some all fibreglass boats in 1981, my Wife’s is 982. I believe they created controversy at the time. The Victorians being naturally conservative declared them illegal, but SA disagreed and allowed them to race. Some years later all fibreglass dinghies were allowed nationally when Smackwater produced a middle of tolerances batch. The earlier fibreglass boats were heavier than ply, so a few composite boats were built. Later the production was better due to improved glass, resin and foam, and experience on where you could go light on the resin. The real advantage of ply is you can easily tweak the design of a one off version depending on your own ideas on optimal shape.
Many of the so called ‘one designs’ have wide tolerances to allow for errors in home construction, so you could play with rocker and sections for different sailing conditions building to the extreme tolerances. For a while the trend was skinny flat boats. I designed some five national winners in different one design classes! The Sabre is in the wide tolerance category, and most top skippers have their own idea which set of compromises [ for the technically minded ‘within the design envelope’] is the fastest depending on their weight and wind/wave conditions expected. Hence still a preference for ply boats by top skippers.
Hi Sue,
I have been using Linos waxed Dyneema for many lines on my boats without problems. If you are a perfectionist it can be eye and backspliced. For the forestay on the Sabre it is easy to banjo, wrap and tuck so they is no problem in easy release. Important for LBG winters. The measurer made no comment so it must be within rules.
regards, Paul
The cruiser division in the NS14s is self selected not according to the age of the boat. The results are based on handicap not scratch, so if you enter with a new boat there is no advantage. In addition they have a heavyweight division which is a scratch event.
The Tasars have age of crew categories like the Sabres, that works well.
The Flying Fifteens has three fleets depending on the age of the boat, which while a ‘one design’ hull, over the years people have learnt to optimize the shape within the tolerances. Another Sabre attribute, but I think like with Lasers, the hull gets tired with advancing age rather being slower compared to new boats benefiting from minor shape improvements.
The Mirrors seem to have prizes for every catergory of boat and crew which keeps the whole fleet happy.
The question is whether the fleet is racing to be top dog, or the majority are in it to have fun. My view is a single scratch and handicap system is the ideal solution plus a single prize for extreme categories on a scratch basis. such over 70, over 85kg. This year I have been race officer for three nationals and several state titles, and know the happiest prize-giving is with a few random prizes thrown in:- best capsize, most attractive colour scheme. etc.
Great game, just right for cold winter nights. Many thanks for posting.
Paul Fitzwarryne
266 ‘Sober’I ended up laminating timber from the remains of the last spruce NS14 mast made. It was well seasoned after 20 years. The result was a ulta light stiff thwart. Following Phillip’s advice on the necessity of anchoring the ends and centre is essential, so I spent some time making tight ends glued in place under pressure. I also used the Riley fittings on the traveller running end.
I acquired a few spares from 991 from her previous owner to bring 266 up to standard after 30 years use!
This evidence suggests that fibreglass Sabres were being built as early as 1981 by Kim Snowball and sold through an agency in Glenelg. I have checked 982 against photos of 1154, another Snowball, to verify she is identical.
From Peter Reid’s recollection 982 must have been produced when the national committee were trying to ban SA built fibreglass Sabres, thus she was not registered as measured. However, she was raced at several SA clubs for over 20 years before I bought her for my wife in 2004 through the SA Sabre Association. She was still set up with the original fittings lay out and Ray Brown sail. Since bought, 982 has been updated with discarded parts from four other Sabres from three different states!
I presume the Victorian concern was that you can get legal shapes from a mold which are faster than from a ply boat. Does this explain why the Botteril mold was taken from an existing boat to avoid wooden boats being outdated as has occured in some dinghy classes?
Thus, the Botteril Sabres were not produced in Victoria until seven years after the Snowball Sabres in South Australia. Of course there is an outside chance Bill O’Toole bought the plans, decided building was too complex, and later bought a Snowball and used number 982 for her.
Paul Fitzwarryne, 266
My wife’s Sabre 982 is either a Snowball or Smackwater, with a label saying it was supplied by a firm in Glenelg. The dinghy previously sailed with Larg’s Bay for many years. The bow had slight foam seperation problems easily fixed with the traditional hypodermic syringe load of resin. I there a way of telling who produced 982? Who built the windward mark boats?
Many Smackwater boats had construction problems. I bought a fleet of Pacers from them for the YMCA, and all were totally beyond repair after 5 years with major seperation problems.
@Andrew G wrote:
A very intersting topic indeed !
Phil is also right in raising this issue of race management. I think we’ve had far too many examples of poor race management in recent years – I’d say 4 of the past 7 fall into this category. (yep – Blairgowrie included).
The race officers either don’t have the necessary experience (as distinct from ‘qualifications’ they have gained) or they are completely unwilling to accept feedback before or during the regatta. It is imperative that all organising committees address this whole area at the time of agreeing a venue – and if need be bring in an ‘outside’ PRO and or starter. .I recreationally sail a Sabre, and spend far more time being a race officer than competitive sailing. This season I am race officer for three nationals for international classes, plus several state championships. Thus, I think some experienced response is necessary.
1.The major problem in getting race managers in sailing is it’s a sport you can enjoy in old age. The Sabre unfortunately significantly contributes to this! Thus, unlike most sports we do not have a large pool of middle aged ex-competitors willing to contribute as volunteers. This could be solved if no one older than 35 was allowed race a Sabre, but you could remain a club member if you were willing to serve frequently as a race officer.
2. Championships are held during holiday periods when few volunters are available due to familly commitments, plus good sailors are off at their own class championships.
3. The majority of sailors know the Part 2 rules but nothing about Parts 3,5 and 6. This is why top sailors rostered on for duty often make dreadful race officers.
4. The Sailing Instructions for a Nationals are usually totally different from those used in club racing, which really confuses some race officials used to local procedures.
5. I fully agree that some race officers hate criticisms and suggestions. The more experienced, the worse they are often set in their ways. The critical point frequently missed is that the championship is being run on behalf of the competitors, advice from them is essential. A briefing before and after a race with the class president/rep is good practice. An effective class association will liase with the race officer months before the event, going over sailing instructions, race locations in different winds etc.
My philosophy is a good event is when the best sailor wins, the rest enjoy themselves and the protest committee is underworked.
Yes, getting a good race officer is critical for success but they are in very short supply and the problem is getting worse. It’s even rarer for a sailor to thank a race officer, the first person on the water and the last one off!
