- This topic has 17 replies, 9 voices, and was last updated 10 years, 3 months ago by
.
-
Posts
-
I was talking to a few people at the nationals about how we can make the wooden boats be more competitive against the FRP boats for longer. Sure when a wood boat is brand new the can take it up to the FRP, but after a couple of seasons they don’t seem to carry the same speed.
Why don’t we change the rules for wooden boats only, to use carbon fibre to strengthen the floors. The cost of this is probably on a couple of hundred dollars and far cheaper than a FRP boat. It would also mean the wooden boats would be more competitive for longer and you could rejuvinate some of the existing wooden boats.
Throwing it out there – any other ideas to make the wooden boats hold their speed/last longer?
Scott
Maybe the min weight is too low to make comparably stiff ,weight competitive, lasting hulls in timber?
There are a number of things you could do to engineer stiffness into ply but it will always add weight…even with carbon.
I think the bow shapes and rocker lines of most ply sabres need optimising, as they are in the foam boats, and the symetry and fairness will always be a challenge.
Not sure the stiffness is really the issue. For a single sail, low rig tensioned class it should be sufficient.Carbon doesn’t belong in sabres. Would probably be best to restrict the glass foam boat rules to bring them closer to ply boats.
I reckon that Scott is right about wooden boats being fine for the first year or so, but progressively less competitive after that.
What makes a hull fast or slow anyway? The main things are the shape, weight (and its distribution) and stiffness.
It can’t be the shape, since the dominant YMS is a mould off a (more than ten year old) wooden boat anyway. Glass boats are pretty hard to build down to weight (my new YMS only has 400g of correctors, not several kilos as mentioned in some other posts), so it can’t be that either. Distribution might matter a little in waves, but Perth was flat anyway so it wouldn’t have made much difference. Stiffness may be the issue, when the wooden boats get old. Two experiments are probably worthwhile – one would be to build a ply hull and sheath the floor in carbon (illegal – but just as a trial). The other would be to have one of the top sailors try a newish timber boat in a regatta.
There is one other thing that might make a difference, and that is stiffening the front of the centreboard case in the timber boats. Even with a new one, you can flex the front of the case quite easily. This can’t be good!
I have a few other theories though. One is that all the fibreglass boats are fast, whereas there is huge variation in the wooden ones. Building a wooden boat to the right shape is a bit of a black art, and its finest proponents are either not building boats any more, or building very few. As fewer wooden boats are built, we are increasingly comparing new fibreglass boats to 10-year old wooden ones. And the really serious sailors will always have newish boats.
This is largely a perception problem. Jack Felsenthal sailed a timber boat to second in the Victorian states, beating all of this year’s nationals top 5 except Scott (ask Scott if Jack was slow!), plus some other very good sailors.
Looking at the fleet in perth, there were so many things that differentiated the sailors. People starting on the third row, tacking into dirty air, not hiking properly, sitting like a pudding in the boat on the run and so on. None of these are the boat’s fault. Murray Smith was probably the only person in the fleet who was genuinely held back by his equipment. I think his hull would have to be 15 years old, and struggled downwind although he was often up with the leaders at the top mark (in fact, a leg in front in one race!)
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
Helter,
Which class would a composite boat be in?Gents,
Before a solution is identified for the currently perceived construction problems, the class needs to determine the scope of its target market – then – ensure the class rules are relevant.
For example – is price for a competitive boat a consideration? Home builders encouraged or not?Hi Slow Hand haven’t heard from you for some time and you are missed.
The composite Hull needs only the stiffening frames (final weight of elements and glue .30 kg) between the bulkheads to stop the possible flex in the top of the centre board case. I have tried a composite and the centre board case flexed but not a much as my wooden hull from the same builder. The hull on the composite is 8mm epoxy foam and very stiff.
I have been told that a forward frame is not necessary but it is easier to fit a frame and it will achieve greater stiffness than extending the floor runners as it ties all panel and deck elements together.
Another additional consideration is fitting a keel internally from the centre board case to the bow stem post. I hear people screaming weight but I have cut all elements for the keel and ring frame from syrian ceder (keel 19/19 mm frame supports 10/6) and 4mm ply and allowing for glue the weight is less than .550 kg.
All modifications can be retro fitted as it will be necessary to remove the front deck to modify the new mast step support.Slow Hand
The composite boat should be with the Glass boats as the hull is a lot stiffer than wooden hulls.
I agree with people being able to build their own boat which should be encouraged. My concern is that if these people do not have a real competitive chance then they will be discouraged and the fleet size may diminish.
Not every body can afford a glass boat or for that matter want a glass boat but seriously if you don’t go glass your chances of winning a Championship or competing competitively at club level are doubtful. Hence to have trophies for both is sensible and supportive of the class and its original ethos.
But
This is not a reason to attempt to make the wooden hull as competitive as possible.
HelterSkelterAnd as a nod to the original philosophy of the class, also a third category with all similar accolades: the builder/sailor who builds his own boat in his own shed in his own backyard. 😯
It’s not too hard to organise. The fleet races as usual but instead of divisions according to speed, you’d have a glass division, a wood division and a DIY trogs division. That might even tempt me to dig out the old wood plane
I am getting confused about what is a composite boat. Composite would usually mean built from more than one type of material.
I see 4 main types of sabres
Plywood
Plywood fibreglass sheaved (most common type of ply construction)
Foam and fibreglass or foam sandwich as it is commonly known.
Foam and glass hull with plywood deck.
The last 3 could all be called composite. There is also timber and plain fibreglass boats but are not common in sabres.Which one are you lot referring to as composite?
Hi Guys
At least this has given some great discussion – I think that there is somewhere less than zero chance to change the rules to make the fiberglass boats slower (and why would we want to??). The only option we have is to make the wooden boats faster. Maybe some of the other option people have suggested would improve the wooden boats, plus having carbon to increase the longevity.
What do we want – I’d like to see wooden boats that the back yard builder can make, be (nearly or ) as competitive as a glass boat. Currently there is a great divide…
Hi Seabreeze,
The best test to see if a new wooden boat is as quick as a new glass boat is for you to jump in one and see how you go.. If you use the same sail and set up, in theory (if the hull shape is good) you should be leading the pack.
So, once Fuse (New wooden boat build 2023) is completed the challenge is there for you..
From my point of view, the first thing that needs to be done to improve wooden boats, is update the association templates for all states (or make the plans available so they can be cut with a CNC router), and then expedite the update of the construction manual. This will significantly help the amateur builder.
More thought should go into the use of exotics on the amateur built wooden boat. I agree with your point of view that a wooden boat will not be as durable as a glass boat, and exotics such as using carbon instead of fiberglass could make wooden and glass boats more comparable over a longer period of time. However boat turnover is a good thing for a fleet, it helps to grow the fleet. And realistically you will continually update a glass boat if you plan to keep winning Nationals, as you will with a wooden boat.
To progress with your forum discussion, we first need to find out if a new wooden boat is as fast as a new glass boat.. Step 1, so the challenge is yours..
Cheers,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
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
- The forum ‘Boat Construction’ is closed to new topics and replies.