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Hi John,
Message from Brett Young, at YMS:
Cut out size for 179 venturi is 37.5mm wide by 82mm long and put approx. ¼” radius corners in. Add turps to the epoxy mix he uses for sealing the edge to soak in further….
Hope this helps
Charlotte
At YMS we use an RF 192 for the bowplate but turn it upside down so the large hole is down and then when you screw it in (with a dob of epoxy on each screw) then those hole spacings will allow you to add a small but strong saddle (RF 94) at the same time. The top of plate is then aligned to forestay angles. This is a lighter plate than the RF488 which we use those only on our Fireballs which carry over 450 kgs rig tension. I reckon you could scale down to the RF 192 on your sidestays too….and yes to bending them inwards to suit rig. Chainplates are the norm for Timber boats as it suits that construction method better, while world norm for FRP is loop saddles as less chance of leaking. If you use saddles on a timber boat you’ll lose your gunnales.
Hope this helps.
regards
Youngi
Hi David,
I’m definitely over next weekend….so if you had good red or rum I’ll definitely come for a visit and see how your ply boat is looking. Are you the same “David” that I’m bringing a set of foils over for?I’m in WA in less than 2 weeks. we have 40 foot container of Sabres, Sabre moulds, Minnow and Pacers. For a small business of only 3 we’re pretty chuffed to be filling containers that size for within Aus. Even more chuffed to have our old Pacer clients rushing back as their imported ones have caused them heartache…..a lot.
so keep some good rum in your cupboard and I’ll see you for sure.
re glass and carbon….both will make timber stiffer. carbon the most stiffest….but when its fatigue point is reached it is literally instantly.
best analogy is….2 windows………1 made of glass…..1 made of polycarbonate. Both clear and see through. bounce a tennis ball off each and the glass one will bounce back further every time. keep throwing the ball continuously and same result…..until…. smash ………glass one has reached fatigue failure point. polycarbonate one will go as long as you do. It occurs from a syndrome of “micro cracking”. this is the same issue in moulded foils. They micro crack over time and will be softer at the end of the season compared to the beginning which makes it hard to control your constants. This is a similar issue in ply boats as thickness is beyond the work capacity need. Laminated timber foils with epoxy glass never reach this fatigue point. Who ever invented trees did some amazing things. In 470’s I have foils still winning at world level after 20 years.
Which makes me think that maybe it is possible to do something better in ply.hmmmm….. Ther are places like Bondall that laminate anything to polyfoams for structure and insulation. I’m not sure what the thinnest 2 ply is available but concept:
1 veneer grain at 0 degrees and A-bonded to 2nd veneer at 90 degrees then A-bonded to 6mm Gurit foam then A-bond veneer at 90 degrees and last veneer at 0 degrees. this would leave you with an unbelievable Panel with no join either as outside veneer would be continuous. It wouldn’t measure (yet) as it as its not plywood but if you put a layer of glass on it becomes FRP. But it doesn’t bend the same as Plywood does but current ruling is allowing non plywood bends into plugs anyway so with that precedent set and plugs being made out of mdfs and various alterations then maybe this panel will pass….. sorry…thinking as I write.
I would surmise that with the other things that are getting through you would have no problem with this and is infact possibly already legal. have to think about that. a lot of people get their own Plywoods custom made as a lot of the production Aussie ones have issues. I’m sure this could be done by yourself just with a vacuum pump and its strength? As you are both tensioning and compressing a linear form and structure in the veneers I reckon it would be STIFFER than current FRP boats….there you go ply lovers and people that like to paint their boat every year lol……………….problem solved…..maybe……food for thought though….cheers
sorry about that. have a bit of a bee in my bonnet as I have seen other classes get destroyed in similar ways. The Sabre was/is the last unaffected Aus Class really as so many classes have declined while what had made the Sabre popular and strong has been suddenly eroded. While the Sabre remains plywood in shape for all construction methods it can regain its strength. The 125’s let someone walk through loop holes and went from numbers in the 80’s at Nationals to about 12 the next year. The Taser was actually an NS14 design and Frank Bethwaite had major concerns about its future as rules were too loose so he added a foot to his design which has evolved into the International and successful one design class it is today.
Sabre sailors and members are generally just happy people that just want to go with the flow and just sail but even though my production is in professionally built FRP boats, that only makes me more determined to stand up for and protect the Sabre we all still want or it will lose the very essence and friendly nature and character that made it popular and is non existent in most other classes. If we don’t keep the design constraints in line with what amateurs can build its loses the very core item that gives this class its soul. Once an amateur builder is unable to build the same shape as one from an FRP builder there is no chance of anything “one design” or equal ever again and the assumption that they’ve lost the race before starting as now racing against the unknown.
speaking of “unknown” I’m not familiar with West 311? what is it?
Hi John,
I’m not a Sabre measurer so my data, experience and opinion doesn’t officially count in this situation and by coincidence I have a difference of opinion atm on a measurement ruling with the hierarchy atm on a similar situation with what actions I believe would fix your problem.The precedent these recent rulings may then allow unlimited designs for the future as not limited to Plywood shapes as in the pst. One of these changes is similar to yours……i.e. a plywood plug has had a curved forward panel flattened and all you wooden builders out there would know that to do that correctly and legally on a plywood boat you need to firstly release the side seam for at least 2 feet and approx. the same amount on the centre seam. This allows for the panel edges to move out at side chine and as the centre seam cant move in as it hits other side panel, so instead they both touch and are forced upwards to find the right spot that has them in equalibrium and matching up on the centreline. This obviously produces a new rocker shape and as the new rocker in effect moves towards the measurement jig this would reduce the rocker numbers. That’s only my opinion that comes from experiences like, attending and being involved at the measuring of over 15 ISAF World Championships and as the Aus Olympic Shipwright for 8 years and ensuring easy and low stress passing of the stringent Olympic Measurement at the 2003 Pre Olympics and 2004 Athens Olympics for all classes. However another builder has recently done that very process of flattening the curved panel and their website states a now “more defined ‘vee’ between the bottom panels with less bottom convex round, and a finer bow. The rocker line remains the same (as flat as is allowed)” . This to me defies the law of physics of “conservation of mass” …..as they’ve flattened a curved panel with no rocker change?! where did that extra ply go when flattened then?
so I’d love to hear other peoples opinions on this. if a plywood panel is correctly flattened what do you believe will happen to the rocker? and do you believe its possible or legally correct to flatten a curved panel with out releasing the outer and central seems?
is the Sabre to remain plywood shaped or has the beginning of unlimited shapes already occurred?
I am saying all this because if you needed to solve that measurement issue without bog, my advice would be to still release your centre seam (but not the outer seam and you probably need to release from you webframe for at least 100mm each way but most likely 200mm. if you can some how now make a 3 or 4mm gap between web frame and hull panel then you can force the hull panel flatter with steam, hot water and weights….and on the boats Ive known as you flatten that curve your rocker will rise and make your numbers reduce.
So the easy way is just add some bog in that area of 3048 and has been legally approved by measurer and committee……none of my plywood in stock has lumps of bog on it though. its just made from wood.. Sharpening that centreline v will help rise the point you need and then sand your centreline v down behind that point at your jig contact point (usually just forward of case slot). By dropping 2mm at jig contact point and building point 3048 up by 2 or more mm you reduce your 3048 rocker by about the amount needed. If you then added a mm or 2 at your transom datum point you would almost return the first 2 rocker points to original( by the “law of thirds” in this case). and as the jig basically pivots on the contact point at case front it would then reduce you rocker further at 3048 by about another 1mm……so then you’d be in easily. a mm is a mm lost. We actually have adjustable metal threads on all our moulds on the critical measurement points to ensure consistency as moulds change year round and over time.
I’d love you to release the panels from the web frame and flatten it a bit and see if your rocker does or doesn’t change. There’s a reasonable chance that you really had to force that ply into that tight curve and centre point as it is a tough point of multiple axis. You may need to get some kind of cutting tool to release or cut through the centreline joint,and even that small release and straightening of panel in its final extension to centreline maye be all you need. You are also allowed up to 5mm of hollow so if it needs a bit extra then you have the scope
Personally, I wouldn’t do anything till you have your first 2 coats of resin or paint on hull as it may shrink a bit and rocker may differ again. Then if using minor amount of bog to do minor changes it will adhere better. Building up your rear point with thick and extra coats of epoxy resin will help the measurements but also help protect from the dreaded “bum on the ground” drag that can occur from time to time.
Give me a buzz on 0411198710 if you feel like chatting about options to drop some weight out of your boat.
cheers
Youngi
and even though the proposed “Sabre Charter” from the SSAV is trying to prevent amateur builders having access to the YMS hull shape (which would make the class even more one design) by trying to prevent amateur fibreglass boats, you now (or very soon) will have YMS moulds in WA, SA and Vic. I’ve spoken to Sly and he’s previously sold just hull shells for the home builder to finish off. We’ve never been asked and I’m sure Craig in WA would be happy to do just hull shells. this would give everyone guaranteed speed and resale value, while allowing the home builder to still make their boat a personal build achievement.
Our hulls are double glassed under the foam supplied by SP/Gurit which is considered the best in the world. I believe a laid up Hull with no other bits would be 2600 and weigh 17.5 Kgs but as our boats are super flat it may be prudent to have basic, yet to be shaped inner cedar gunnales glued on, webframe glassed in and maybe keelson to hold the hull safely in more correct shape and that would be 2900……but then the hard work is done and the strength benefits of the FRP can be used for the hull while ply for the decks and tanks can give that personal touch and style and plenty strong enough. a win win……particularly for group building bees and we would certainly discount for a multiple number. I almost see the romance of a bunch of old sea dog mates , for example, Harold v George v Barry, all trying to out do the others in how many 1/8th strip inlays of rare timbers that they can put into some custom veneered ply they’ve picked up somewhere that they wont give away…..you could end up with another 100 YMS shaped hulls but not one of them really from us but from 100 individual sabre personalities instead, but all going fast and equal speed…. that’s what the Sabre is about. Good, fun, intelligent individuals. can build your own individual boat but with a fast hull your resale is far higher and safer….
We even have a roll of glass that has a wood veneer image printed on it so theoretically you can even have an FRP hull that looks like timber….maybe….if I can pull it off
Some good ideas and positive thinking from all so as a learned and aging builder I thought I ‘d slightly correct some facts so we all head in right direction.
yes..Carbon is stiff and infact has an elasticity modulus (percentage of stretch prior to breaking point) of only 1%. most softening plywood would be around 4 to 6%. that’s a big difference to try and keep the two together. one wants to sit rigidly while the other wants to flex and wobble…….eventually they’ll part ways like an incompatible marriage. fibreglass is actually closer, ranging from 1.8 to 2.8% and is cheaper and more readily available in lighter options. Carbon comes standard as 200 gm psm but anything lighter or heavier costs much more due to the refining work needed. Carbon 200 can vary from $35 a mtre up to its spike during Iraq war and airline building boom of $135. Any epoxy resins below a 4:1 mix ratio arent worth using with Carbon as the 3:1 and 2:1 epoxys are substantially weaker. In fact in single or thin laminates like this then vinylester is actually better, even with bonding to timber ( as long as non oily and dry). Its more stable and resistant to heat and good enough to hold helicopters and submarines together as they cant use rivets.
so for a Sabre hull a layer of carbon at 1.2:1 wet out ratio with say west system epoxy (more user friendly and much cheaper than SP) would weigh approx. 3.04kg!! and cost $365 at trade price. you can get fibreglasses at 86 and 105gms so even by using the heavier vinylester at 1.3:1 for the 105gm glass, the weight would be approx. 1.65kg so about half the weight and price would be(glss $9pm and vinyl $8pl) only $71 or if epoxy used then $98.
I see much of the present day plywood boats problems as these: how do you know your shape is fast? the YMS and Botterill shapes came from 2 of the fastest ply boats at that time and so every one that comes out is a clone in shape and speed as by making a mould from those actual boats means 100% the same plywood shape. this is the nearest defining point as per the rules anyway…to be as near as possible to a complying plywood boat. Our designer, Rex , didn’t even bother with rules as everyone was to have the same shape off the same templates…..its seems simplistic but when you think about it it’s actually a great way to control shapes……don’t need jigs or masses of templates. if it doesn’t match plywood and the original templates then it isn’t a Sabre
These days good plywood is hard to come by…..very. We only use gaboon/cedar ply from the Israeli manufacturer. There is actually a large amount of ply in our Sabres and each time we’ve used 2nd best we suddenly struggle on weight.
In the days that the Plywood boats ruled over the FRP ones (I felt we’d never start winning at one stage), people had more leisure time and could burn an extra 100 or so hrs hollowing and pairing ribs and frames down for weight. Boats were normally in a nice warm and non humid dining room. Wives now banish such important things to the shed or man cave. A decrease in 3 degrees can see you use up to a third more resin for no real benefit. Humidity is a weight and longevity killer. Our moulding room remains at 21-23 degrees and 39% or below in humidity all the time unless we are baking. Our foil and epoxy room remains at 26 degrees……makes a huge difference to amount of resin used and strength of cure. Back in the ol’ days you couldn’t get economy versions of epoxy as with the 3:1 and 2:1 types now available. These 2 don’t even rate close to the 4:1 and 5:1 versions from West and SP for strength and useability. I think about half by memory but certainly a very noticeable difference.
In the past the ply boats were stiffer and lighter than the FRP boats. Plywood by its own structural sandwiching and glue joints is naturally and inherently stiffer than foam……just FRP builders have improved their techniques, while Plywood Sabres have been built with out the spare hours to chase each gram, heavier and lower quality ply, heavier and weaker epoxy resins and less warmth and higher humidity out in the “man cave” .
Even after taking a mould from Bates’y Hullabaloo (with permission) in 2003 and although this boat was a few years old already, our YMS boats didn’t win their first Sabre National till 2007…….so don’t believe the hype about FRP being faster. Plywood was still faster than even the YMS FRP boats till Hullabaloo just simply lost its “edge”…..ok and maybe Batesy was carrying more of an investment portfolio than a “six pack”….but its still a very fast boat…..underweight…..not glassed and 14+ yrs old…. so save your bickies and buy the expensive plywood (which is more expensive than same thickness foam we buy!!!!), get the good epoxy (which is 5 times the price of vinylester…who said timber boats are cheaper? not if you build them properly)….and send the wife off to the mother in laws so you can build in the dining room like all good timber boats were made in the past. Alternatively, to aid this experiment, maybe shush the naysayers but mainly for my own curiosity, I would love to build a plywood hull out of one of our moulds and will donate the use of my moulds, my time and factory overheads for someone also keen to do this and them pay for the plywood and materials etc. we would vacuum form the ply into the hull mould and crank our mould room up to give it a crisp cure.
the Sabre originated from Plywood. we need to ensure the very thing that brought the Sabre to this level of success is not lost by the original plywood shaped and built boat being uncompetitive. Consistency of design, competitiveness and resale value is the keystone to most successful classes and we have seen this in danger in recent times. Time for sensible heads and dialogue to turn this around……..
cheers
Hi Magic,
good work with building your timber Sabre………….
weighing time…….top measurers and the ISAF norm is to suspend your whole boat from a well calibrated digital set of scales in a room with no breeze, suspended by 3 or 4 points of your boat or in slings and these ropes and slings already zeroed off on the scales……blah blah.
now to the real world. if both ends of your boat are at the same height e.g upside down on two drums of same height, then if you put your scales at one end and then at the other end, then the added total will be pretty correct (if your scales are). Most digital bathroom scales are in fact more accurate than most people would think but are usually designed for best accuracy from 40 to 100 kgs…….one end or half of a Sabre is in the inaccurate range.
so even though this may seem a little inaccurate we find this gives us exactly the same result as the any of the top “official” methods. Place your scales on a nice flat solid base with a bit of padding on top. if possible check it with 40 kilos of something on top to calibrate.Get your sabre, on edge on its gunnale and ontop of your scales and test for balance point for and aft (so scale not confused) and then the balance point towards or away from you as you hold the top gunnale of the boat. you are looking for the exact point where you can literally let go of the boat and you are not exerting any load or force on it……..and that is your boat weight!
I laughed when I first saw this method………and we have so much faith in it now that we don’t bother with hanging any boats to check the weight anymore. Spring balance scales that most people to use to weigh boats are in fact notoriously inaccurate as the k-factor of the spring is effected by being banged or dropped,fatigue, temperature and humidity.
hope this helps.
regards
Youngi
Hi Daen,
why have official reps of that committee and the measurer reported on these forums and in emails that “a plwood strip” was used to check the measurements then? We can all only go on the facts reported and at no time ever has “2 full sized panels” been stated to me our anyone I know.
that’s why third hand reporting is always treacherous….and hence why I went in and saw that plug for my self and spoke to Jim face to face myself. It was in fact me that reported that the rumours of a “radical” hull shape was grossly incorrect but the look on Jims face told the story when quizzed about the methods used to change the shape and the precedent this set which allows all boats and moulds from that point on to exploit this.
the gang from YMS sincerely hopes so too. He and Doug Bennett are our satirically nicknamed “Grumpy and Grumpier” teams as they play off each other like the pairing in the movie but are always smiling and bring a laugh everywhere they go. My face always hurts from smiling too much whenever I spend time in their presence.
anyone that can bat that far out of his league to win his beautiful wife over like he did, insist on his Sabre to match his ol’ school rugby jumper and still hold his own on the race track to even beat all comers including past National Champions from time to time, all at the age that sees us reaching for calculators instead of using fingers……makes me feel he will win through what ever see’s him in there……and whatever higher power you believe in will hopefully be keeping a watchful eye over him.
best wishes John……
If the plug measured originally and the panels curve then flattened so then being narrower does it still measure with that much size change.
for 31 years FRP have all come from moulds from ply boats……all of them. I’ve been building FRP Sabres for 27 of those years and not once have we manipulated that shape.
for last 2 years all Ive been constantly asking for is obvious loopholes to be closed and the rules tightened so I can protect my financial investment to build 2 new moulds of exactly the same shape.
2 years later its still exactly what Im trying to do. close those same loopholes as people are trying to exploit them and build 2 new moulds of the same shape that we’ve had for 13 years.
During my last, and I thought productive phone call with the National Measurer I was told the FS2 plug would be checked with a sheet of ply. A sheet is still smaller than the full panel but hast vastly different bend to a strip.
for many many years 420’s, 470’s Finns and FD’s were all made with strips of cedar. The fastest Contenders from Italy still are. I think every one would agree they are a vastly different shape to a Sabre.
We both agreed that Rhino and AutoCAD could not post measure that the shape re emulating ply……. as falsely reported on another stream.
And when a panel is flattened, the angles at the chines changes and the panel spreads out past centreline and the line of the side chine as well so needs cutting down on the 2 edges and/or side panel moved out (which is too hard on an internally glassed plug)….so the panel effectively become smaller in width than when first taken from the templates.
I have been following this discussion and consider there are several issues to be resolved which were not properly addressed prior to the Rules Change.
In Wooden Boats it is necessary to stiffen the Centre case by allowing two frames 90mm each side of the centre line from the Centre Case Bulkhead to the Web Bulkhead. The twist in the centre case varies boat to boat but both of my boats have moved 15/20mm each way with the flex being in the Centre Case bulkhead.
Also a ring bulkhead should be allowed half way between the Web bulkhead and the inside of the bow stem post. This will assist resolving the construction issues and stiffen the bow and bottom panels forward of the Centre Case Bulkhead.FRP Boats by there very construction are much stiffer which gives them a substansal advantage which cannot be matched in wooden construction.
I consider it is time to stop the bickering and as the Association Rules have now clearly defined two classes of boat, have two Championships Divisions with equal prizes.
HelterSkelter 1906
I agree with Wand as far as glass boats having lite ends but I suspect there would be a corresponding lack of stiffness which would cause the boat to soften quicker but for one championship what the heck.
I have a wooden boat built by a reputable class builder and paulownia was used to achieve literness but cracked and split in ALL high stress areas glassed or not which has required the deck being removed and the boat framing rebuild this time with syrian cedar. To my surprise the weight only increased by 0.85kgs. Yes I was careful with measurements and not using excessive glue and I didn’t have to glass to achieve strength. My boat is noticeably stiffer and quicker upwind.
It is hard to know which is better but I don’t want to sail a one series wonder. I would like to see a Rule requiring a 41kg minimum hull weight with allowable correctors to 0.5kg equally attached the top centre of the bow and top transom bar. This would not make it worthwhile to build a lite hull.
To stop glass builders resetting the weight to the centre of the boat appropriate Rules can be introduced.
Alan Wilson 1906
