Optimist Prams [Archive] - The WoodenBoat Forum

Lulworth

02-07-2008, 01:48 PM

Yup. This one (and two others). It was a royal pain-in-the butt to build it so that it would measure in (it did, to my great relief). I'm more of a what's-a-few-mm-between-friends kind of builder but the tolerances on the plans are +/- 2 mm in some places and +/- 5mm in others. The boat came out nicely and is light, stiff, and fast and usually the only one (in RWB) at the large national regattas. Of course the coaches hate the thing-- don't know what to make of it!
http://im1.shutterfly.com/procserv/47b7cc27b3127cceb1331ef1400e00000035110AaOGTZmzaOW IA

Tom Lathrop

02-07-2008, 02:43 PM

Thanks Lulworth,

Your experience with the plans mirror mine. It is, by far, the worse set of plans I have built to. All measurements other than radius on the rudder is actually -0, +2mm which is the same as +/- 1mm. That is ridiculous. The only way I can see to meet that is to cut to a low measure, shape the edge and build up with epoxy and paint to the middle of the tolerance. They do not give a normal set of offsets, just measurements at various points and the plans do not specify the height of either sheer or chine at the ends of the boat. Bummer. I have spent the time to build a very accurate female mold so that all boats will come out exactly alike. The down side is that, if one boat is off anywhere, they will all be off. We will build 11 boats this spring to get a local fleet started.

I built a couple of the original Opti's in the 1960's and they were a pleasure to build and sail. My kids and wife learned to sail in them.

I guess that is what happens when a group of "concerned parents" gets into the game:( Europeans at that:rolleyes:

That is a really nice looking Opti. most of ours will be a bit downgraded since they will need to be used in a teaching class with beginners. I have seen what happens to other Opti's used for that. Rubber bumpers all round would be nice.

I wonder what Clarkie Mills thought of what they did to his simple little kids boat?

Stiletto

02-07-2008, 02:49 PM

Are wooden optis still competitive?

Lulworth

02-07-2008, 03:31 PM

Quote: "Are wooden optis still competitive?"

Yes. Funny that you, a Kiwi, should ask! I did a lot of research and found someone even nuttier than me living in ... New Zealand ... who shared some good ideas on how to optimize the hull shape. His kid, if I recall, won (or placed 2nd) the NZ Opti Championships. My kid here in the US does well in hers for the level of commitment that we are willing to make. She also sails a new, state of the art fiberglass Opti and her results are better in the woodie.

A funny (to me) story ... I was having a fairly animated discussion with a local boat builder of some repute about the use of tortured ply (intentionally adding compund curves -- within allowed tolerances of course -- to the sides and bottom) to increase stiffness when he paused ... looked pensive ... and said "... it's easy to get kooky about this stuff!" He's right!

And Tom, I actually built (or partially built) four of these damn things but only two measure in. It would have been easier if I hadn't been goofing with the limits (to match the 'glass ones) but the real hassle is on the bottom which tends to form a hollow where the trunk emerges. I added a bit of lateral curve to reduce this effect but from what other builders have said, its inevitable (there are some good solid-mechanics based reasons for it) and has to be filled with microballoons or something.

Cheers, David

David Tabor (sailordave)

02-07-2008, 04:11 PM

http://myboatyard.homestead.com/OPTILAUNCHING.html

This will show you pics of my boat (built for my kids; used twice:() On that page there is a link to a few pics of the building process... Wish I had put more up...

It's sitting in my basement. And yes I was very careful to build to spec. Of course the tolerances are pretty liberal.

Ian McColgin

02-07-2008, 04:36 PM

The plans we lofted from for the Setauket Yacht Club's first sailing program - was that 1964? - were pretty good but our building was not. I think there were about a dozen dads involved in the assembly. With the help of a local shop teacher, I'd made all the panels and battens and they were all just alike to very good tolerances. Nonetheless, no two boats were quite alike. Empiracle evidence suggests that rum and coke leads to a less fair hull than scotch neat.

Tom Lathrop

02-07-2008, 04:49 PM

Frankly, I don't think a boat can be built within the International tolerances that will be measurably better than any other. There is a whole lot of mumbo jumbo in any class about this and some classes allow some significant departure in shape. Usually though, something is given up for some other gain. In the Opti, about all that can be done is to change the rocker a little bit. At +/_ 5mm (3/16), you aren't going to make much difference. If you don't leave some cushion on the tolerance, the boat is bound to move a little bit and make it illegal somewhere.

I redesigned the Windmill for composite building in a female mold, just like I did the Opti. These boats have been 100% competitive with the best fiberglass models and I see no reason that that would not be true in the Opti.

Lulworth, that is a great looking sail on your Opti. We will probably not go that route with our boats for economic reasons. Any parent who thinks their little star should race in sanctioned events will be "allowed" to buy from the best sailmakers for those races.

David, I'm looking through your site to see if I can find any tidbits to help our builders. Nice boat. Does you rudder fit the tolerances?

Wild Wassa

02-08-2008, 12:18 PM

"These boats have been 100% competitive with the best fiberglass models and I see no reason that that would not be true in the Opti."

Except there is all this black stuff now popping up on the Optis which is hard to match. A carbon Opti at 40lbs would be somewhat competitive.

The lose wording in the changes to the Opti, made in 2006, were only meant to allow carbon masts and spars but things haven't been so simple.

At the Canberra Yacht Club they settled on black bits for the junior kid's racing fleet, the emphasis is on racing. Toppers are the kid's sail training fleet.

http://i225.photobucket.com/albums/dd301/WildWassa/OPTI.jpg

Warren.

David Tabor (sailordave)

02-08-2008, 12:51 PM

David, I'm looking through your site to see if I can find any tidbits to help our builders. Nice boat. Does you rudder fit the tolerances?

I haven't done anything w/ that boat in years... but IIRC I did measure it out as complying. I knew the kids weren't going to race, but I did want it to be legal.

andrewe

02-08-2008, 01:32 PM

In La Rochelle and other places around here, they build the trainers out of aluminium. No problem with bashing about, though I doubt they would measure after a season.
Andrew

Lulworth

02-08-2008, 01:48 PM

Warren,

There may be a bit of a mix up here. Carbon is not allowed in the opti (certainly not in the hull or mast). The lay-up schedule for glass optis and the blades (unless wood, in which case they must now be ply) is also extremely tightly defined (type of glass, weave and weight) -- in any case there is a minimum hull weight and in the nationals every boat gets weighed. In fact, there were a few carbon tillers out there for a while but the rules were changed in 2006 to prevent their use (unless grandfathered). Similarly, the mast must be Al alloy or wood. Some of the kid's parents pay stupid amounts of money (guilty) for black anodized spars of 7075-T6 Al but no way is anyone using carbon. Yes, optis are stupidly priced and differences in equipment don't really matter when your a kid on a line with 100 other boats and can't get to the front row at the start.

As far as building a faster 'glass opti, there isn't much to work with except a few mm of shape, the orientation of the glass but not the layup, and the wieght distribution. A wooden boat (the one above) is marginally better in the wieght distribution (as measured by Finn-style swing test) but that requires absolute care in keeping the ends light.

Cheers, David

Dan McCosh

02-08-2008, 02:23 PM

Wasn't the point of the Opti to have the kids build the boats themselves, then go sail them? Why else a plywood box?

Tom Lathrop

02-08-2008, 05:24 PM

Wasn't the point of the Opti to have the kids build the boats themselves, then go sail them? Why else a plywood box?

That was partly the intent by the Clearwater Optimist Club which asked Clark Mill to design the boat as an alternative to Soap Box Derby cars. The original Optimist Pram did and still does offer great fun at a lower level of competitiveness that was first intended.

From my experience, it is more difficult to build a competitive small sailboat of fiberglass than one of wood. That is, if the class was originally designed for wood. When weight is restricted to a low minimum, wood offers greater stiffness (generally the ruling factor) than fiberglass. Most fiberglass boats resort to some kind of core material to achieve acceptable stiffness and meet the required minimum weight that buyers insist on.

When Opti's opt (pun intended) for carbon fiber, I will walk away.

The only significant concession my boats (11 Opti's at the last count) will make to being competitive is that I will be using 12mm ply in the bow transom. After looking at some other trainer Opti's, this is a concession to dock ramming.

Stiletto

02-09-2008, 12:14 AM

Lulworth, I asked because I sold the opti a couple of years ago, the kid is now 30 and I havent had anything to do with them in a competitive sense since he sailed her, the ads I have seen led me to beleive that the hot boats were glass, it is good to see that wood is still doing it.

jp4sail

02-09-2008, 03:31 AM

Some nice optimist pics...

http://bp3.blogger.com/_1CDZ7Ya8Ni0/R6iGTQegOCI/AAAAAAAACqg/J0zf8_Yuspg/s400/CAPIZZANO_2085.jpg

http://bp1.blogger.com/_1CDZ7Ya8Ni0/R6iGhwegOFI/AAAAAAAACq4/HEytAA-s43I/s400/CAPIZZANO_2081.jpg

JPaes

adampet

02-09-2008, 07:14 AM

Some people will surf anything!

YIKES!

Adam

Tom Lathrop

02-09-2008, 07:43 AM

Many thanks for those photos. I will use them for recruiting parents to the program. NOT:eek::eek:

Hwyl

02-09-2008, 08:00 AM

I redesigned the Windmill for composite building in a female mold, just like I did the Opti. These boats have been 100% competitive with the best fiberglass models and I see no reason that that would not be true in the Opti.

Tom does this mean you are building plywood opti's in female molds (jigs).

and unrelated, isn't there a relatively recent change allowing a thicker bottom in plywood boats.

Tom Lathrop

02-09-2008, 11:33 AM

Yes, I use a female mold into which all hull panels are placed in accurate position before any fileting and taping is done. Other bulkheads and inwhales are also installed before the then rigid hull is removed for finishing.

The plans I have are presumably the latest and show that the bottom can be either 9mm or 6mm but that the total thickness under the stringers and hog must be a minimum of 15mm. These work out about the same but the 6mm bottom panel saves a bit of weight so that is what we will use.

If someone will give me a push on how to post photos to the forum, I will post some of the mold. I used the search thingy but did not find any of several posts that have done that.

Wild Wassa

02-09-2008, 12:39 PM

"Warren, There may be a bit of a mix up here. Carbon is not allowed in the opti (certainly not in the hull or mast)."

"In a vote sure to spark global controversy, the International Optimist Dinghy Association voted today at their annual meeting to allow radical changes to that most venerable of junior sailing classes : the Optimist.

Carbon fibre is now allowed as a recognised material... and through a loophole in the rule change, may be used for ANY part of the boat including the hull."

Tom, the above was grabbed from a sailing site.

I don't agree with the use of carbon unless the class allows it. Even some Sportsboats like the Elliot 7s have not allowed the stiffening of hulls with carbon. This has been done to keep the cost of the boats from blowing out.

Just imagine $25,000 carbon Optis for kids under 45kg. The kids could weigh twice as much as the boats. There are plenty of boats on the water racing that don't pass measurement. In general regattas excluding Nationals, no one measures boats, or not often, not even in State Titles here are all boats measured. The notification to Skippers just tell the Skippers to bring their boat and sail measurement certificates with them to regattas and they have not even been looked at, I notice.

Some guy here built 7 illegal Flying Fifteens after he made a mould off a British Championship boat when she was brought here to race, without the knowledge of the owner or the Flying Fifteen Association who limit the production of boats to 50 new boats a year ... so anything is possible. 7 extra boats is a big chunk above the 50. There is probably a fully carbon Opti already, if not several.

I've got access to 6 brand new Optis and I've already got a dozen metres of carbon ... now that would be rude.

Warren.

Hwyl

02-09-2008, 01:33 PM

Warren, I googled your quote and found it on a French site "Voiles". It must be a spoof that got away because of translation difficulties.
It goes on to say:

The rule change was supposed to just cover the boom and mast, this is an unintended consequence of vague wording, but the council has no intention of changing it. We are rather excited, frankly, about the prospect of a 40 pound all-up boat." said Optimist secretary Robert Wilkes. "Thanks to Viagra and other 'E.D.' medications, the average age of fathers with Optimist age children has increased by nearly a decade since the 80s. Boats are heavy. Backs are weak. Hauling an Opti hull off a roof rack loses its charm after the 50th time you've done it. I can't wait to see the first all-carbon hull, I'll bet I can lift it onto my Volvo wagon with one hand."

Said Opti parent Beaurigard McTavish: "Let's be perfectly honest here, all this happy talk about sailing being for everyone is balderdash. It's for the children of the gentry. So what if an all carbon Optimist costs £8000? The higher cost will keep some of the rabble out of our nice, Corinthian sport."

Very dry British humour to be sure, but humour nevertheless.

Wild Wassa

02-09-2008, 01:59 PM

"The higher cost will keep some of the rabble out of our nice, Corinthian sport."

Hwyl, well, I would hope it would Skipper. 10 year old rabble should not be encouraged? Although I think the high cost is already shocking and affecting, because some of us have ended up here as virtual sailors.

Hwyl, did you read the bit about the 7 illegal Flying Fifteens? There is one of the boats at the Canberra Yacht Club, called 'Ziff'. She is so well made she has passed measurement and her Skipper and I came third in South Australia in the Flying Fifteen State Titles in her. This is not a joke, she is beautiful. She has a stunning quality finish on her hull. The guy that stole the design is no slouch as a boat builder. He has very fine quality skills for a boatbuilding criminal.

Warren.

Hwyl

02-09-2008, 02:10 PM

Yes I read that, I've seen illegal FF's too. I'm looking at one of Uffa Fox's less stellar, but most popular design for myself at the moment.

I got out of Cape Cod Frosty sailing because even in that class there was an arms race, the regulations specifically banned fibreglass on the centreboard, so buys were laminating in carbon, back in 1992. If I remember correctly, the rules said blades must be made of plywood, and people were laminating veneers and carbon and calling it "plywood".

I'm hoping you agree that the cabon Opti thing is a joke

Wild Wassa

02-09-2008, 02:19 PM

That is why I posted the "rabble" quote.

Anyone who would want to discourage rabble from sailing has obviously been sailing in Australia and has returned home suffering from both culture shock and remote madness and become a zealot wanting to clean up the sport. They will go to any lengths to do it after sailing here.

Here carbon used contrary to class rules, is very common, in many classes. I say to owners, carbon isn't allowed under the class rules, and they say to me, "I'm not class racing, do it." Then a week later they are regatta racing claiming on the race entry forms that they meet all the class rules. I can't dobb them in, it would break their client confidentiality. It is up to others in the Class to protest them ... and it is very hard to see well faired carbon under flowcoat or paint.

Warren.

Tom Lathrop

02-09-2008, 02:50 PM

A barf bag is never handy when needed:p

Sportsmanship has never been all pervasive. Is it now getting as bad as you say? Of course if the minimum weight limit is maintained and each synthetic boat is required to have a longitudinal and transverse moment of inertia test certificate, our wood boats are still equal in all but cost.:D

My test of photo attachments did not work.

Wild Wassa

02-09-2008, 04:51 PM

Sorry, Tom I thought that the changes were genuine to the class rules ... until Hwyl posted the article that ended in a joke. A weak effort by the original poster.

I raced during Scandia Geelong week last week and during the Melbourne to Geelong Pasage Race some boats were using their motors to advance their positions, being a handicap event. When we would come up to under 100m from them they would turn their motors off, not realizing that the sounds of their engines were travelling hundreds of metres on the wind. We would get past the boats by about 100 metres and they would turn their motors back on and sound would start again. We noticed this happening with 3 boats. One of the offending boats put us out of a place at the end of the week, in our division.

He could have been using his motor to charge batteries and not use the prop, but the givaway was how quickly we passed them when the engine sounds stopped.

Warren.

rbgarr

02-09-2008, 05:08 PM

Warren- Do you have a confidentiality clause in all your contracts? Is it at your insistence or theirs?

fair&fair

02-09-2008, 11:32 PM

HWYL, the rules for a frosty board do not state that it must be plywood. A plywood daggerboard in a Frosty is a stupid way to go, as it will flex way too much, especially given how high aspect the foil is in the first place and the need for stiffness being as paramount as it is. The rule is that the board has to be wood and that no glass/carbon/kevlar reinforcement can be added. The stiffest Frosty board I have seen is all wood and very clevely engineered with purple heart, ash and cerdar as a core. This board is markedly stiffer than an illegal one reinforced with carbon that was tested against it.

Now, on the subject of the Optis. I haven't read the newest rule, but I can't imagine them allowing carbon. When I was racing Optis at a very high level some years back, the boats we raced were far more refined than the boats of today. Different manufacturers were able to tweak the lines of the boat to a much greater degree than is now allowed, and consequently, varying manufacturer's boats were quite divergent from one another. Given that the class has essentially moved in the direction of class issued molds with their new measurement requirements, I can't see the introduction of carbon being something that they would do. Funnily enough, a carbon mast, if braided, would be cost competitive with what a souped up aluminum opti spar would go for. This speaks to the insane mark up of all things opti.

When I was racing Optis, I was always jealous of the kids with wood boats. This was not out of love for wooden boats, but rather an understanding that these boats were stiffer than the glass boats. There were few wood boats competing, but those that did...did fairly well If I had kid racing today, I would get him/her a pre 1995 boat, probably a Winner mark 6 or 7. These older hull shapes are far more refined than what is mandated these days, and they are grandfathered under the rule.