An open 8 Footer for adults?

skyak and Whitedwarf,

I have thought about the same thing for a long time. In all urban areas there are many apartment dwellers near the water front, but it adds considerably to the cost and expense of owning a small sailboat if you can not keep the boat in your aprtment or car port. I have one friend in a beachfront condo that the association will not even allow him to store a kayak on the roof of his car in the parking structure. It either has to fit in a 3'x10' storage locker, or in his condo.

I have deigned and built him several hard shell take apart kayaks, and he owns many folding kayaks and canoes, most of which he does not use anymore (takes too much time to set-up). I have long thought that a skin-on-frame folding sailing dingy would be a fun boat just for such an customer, but he tended not to use his folding kayaks because they were just too much trouble to assembly/disassemble every time he wanted to use them. they are also much more costly and heavy for equivalent non-folding boats. So either it has to be very easy and fast to assemble, or almost "ready to use".

I think limiting size and weight is a good way to go, it keeps them simple. I would go a bit longer, like 10 ft, but that makes them that much more trouble to store. I agree that the performance of an 8 ft hull is rather underwhelming, and frankly disappointing. But there are many areas where boats under 8 ft do not need to be licensed and registered, so there is further economy for those potential customers.

I do not see the self-build issue as such an problem, many people build small boats/kayaks in their apartments, or they can go to the many local boat centers where they have classes, faculties and tools to use on building their own boats ( there are four such "schools" within two hours drive of where I live, and I am not that close to the Puget sound). But I think it would be best if the rules were open enough where people could buy a suitable existing boat within the rules, and either use it as is, or do some modifications to it to make it more competitive.

Some comments on your proposed rules:


Length - 8 ft/2.4M

I like it, but with just a bit longer its utility and performance would be better, like 10 or even 12 ft.

Max Spar Length - 4.3M – Fit in the roof of parking space

I would also limit this to a single, one piece spar. There are those that would assemble a mast of several smaller ones, making it more difficult to sail and cost much more. I would also limit the mast material to wood or aluminum, also to keep costs down. You might consider a standard mast, like one off a Lazer or something that is real common, should help keep costs down.

Min hull weight - say 35 kg. - eliminate the high tech/high capital designs

Max Hull weight – 55 kg – its got to be car-topable

I like it, you need to define it though, bare hull weight? Just to be clear.

Beam – unrestricted – effectively constrained by weight restrictions

you will have some that build really narrow hulls with very large "wings", so only very skilled sailors can use it, and most will drop out of the class. Like what happened to the original Moths. I would say limit it to 1.5 meters max, it also keeps it portable. do you want to control the hull shape in any way? I hate limiting creativity, but a developmental class always devolves into a few very difficult to sail but very fast designs, and all others drop out. Perhaps specify a required min displacement weight of 200 kg? this should keep the waterlines fairly wide.

Sail area – Would 6.5 sq M be too much?

You might keep at an even 6 sq M. that is a lot of sail for such a small boat, but it is meant as an adult class. the El Toro 8' dingy has only 4.55 sq M, so a full 6 sq M would be a real handful. You might consider an "entry level" fleet with a 5 sq M sail, and the "advanced" fleet with a 6.5, or even go for the Laser size sail at 7.06 sq m, to allow the class to use a Laser rig. But I would not limit it to a Laser sail, just allow it as an option.

 

WD

Somewhat agree with Petros on the rig selection, and appying the logic to Aus/NZ.

When John Spencer designed the Flying Ant in the 60s he used a P Class sail for the main, as these were by far the most popular junior racing dinghy at the time and cheap 2nd hand sails were plentiful. (All in New Zealand of course)
It almost looks like the fire Bug rig has similar dimensions to the P Class but with full length battens. Do you know if this is what Spencer did with the Bug as well? Many of his boats were designed with a mind to keeping the costs down.

If you can adopt a rig platform common to a racing dinghy in your area (flying 11, mirror, or whatever. That will alow the builders to buy used equipment and you will be able to keep the costs down and make it more attractive to families newcomers to the sport.

I read of the Bug building project at Lidsfarne Club in Tassie, in the Australian Boat Building Magazine a couple of months ago. Instead of running the normal learn to sail class that just turns into a child minding scheme. They asked the parents to pony up with $1500 to fund the build of their own boat as part of the group building scheme, where the parents and kids did all the building work themselves. It meant that the kids didnt just dissapear as soon as the classes finished due to not having a boat of their own. Great idea and seemingly sucessful for the club and class as well.

Good luck with your project

 

Reply to Petros

Thank you for your thoughtful comments, Petros.

The length of 8 foot is the height of carpark ceilings mandated by our local governments. If the boats are to stand on their transoms, in such spaces, that is the length we are stuck with. I wish it was a little longer too.

Weight would be specified as hull weight, the weight of the largest component to be lifted from the roof of the car.

Beam - My thinking is that should a guru sail a narrow gutted shell; well on an eight footer, all he will achieve is a deeper furrow in the water and perhaps go slower than a less radical design. Part of the fascination of this project is to drive towards an optimum in this dimension. 200 kg sailing weight would never plane, so I would not encourage that concept. Let's see if the thread develops any other solutions to this one.

Sail area, again, lets see what develops.

Thank you for your interest.

 

Reply to JRD

Reading the Firebug website, I believe I read that John Spencer thought one of his better decisions was to move away from the P Class rig. The 'Bug has one full length top batten, and two partial ones.

Your right about extra cost for negligible benefit, if another classes rig fits, well why not, but here is the problem, none of the eight footers, apart (arguably) from the 'Bug have a rig big enough for adult racing, and the next size up, that I can think of, is significantly larger.

Do you have an example in mind.

Thank you for your feedback.

 

8 foot skiff and a good old aussie 10 footer...... too much sail maybe?

A flying Eleven has a 6m2 mainsail according to their website. You may just have to recut the sail a little as you would sail it without the jib. It really depends on what is local to you but a racing class is good as they tend to replace sails often which makes second hand ones available.

 

I think you misunderstand me, not that sailing weight will be 200kg, but that the hull must support 200kg. At 8ft long, that would pretty much set the waterline beam to something that your typical low time recreational sailor can handle, and it makes the boat useful for recreational sailing as well. to make them practical sailors you need to set more hull parameters.

with no beam width in the rules you will have people designing very narrow hulls, like a single hull on a catamaran, with 8 ft wide wings to put their weight as far out as possible. this is a fast boat, but not a very practical one that few have the skills to operate. like this;



this kind of boat is not very practical except for racing, and takes a lot of skill to operate. I also think this is far from your intended purpose. You need to have a beam limit, if anything else to keep them practical for car topping. I think 1.5 meters is good for cartoping, you could go more 2 or even 2.44? Max beam.

One other thing is you need to keep sailboards from dominating the class by putting a rule that all lateral loads from the sail must be transmitted thorough the rigging or mast to the hull. are you going to allow trapezes?

 

Reply to Petros

I quite understand the desire not to create a smaller International Moth, and agree strongly. I used to race a Intl Moth, it was built to a design called a Stockholm Sprite, by Chris Ayers. Multiple designers, in one class, not a one-design.

While not allowing the extremes of foils, or windsurfer rigs, I hope to see various designs and designers competing. Some will go for skiffs and some scows.

Again refering to International Moths, they need to craft their rules carefully to prevent the creation of catamarans, and the eight footers will need similar careful drafting. How would you prevent wings achieving a minimum beam measurment, while the hull below is extremely narrow?

If you impose a minimum weight that must be supported by the hull, does that preclude a double bottom, self-draining design?

The project becomes more interesting as you dig into it.

The rules would clearly not be finalised until after the regatta in March 2014.

Please keep the feedback comming.

 

Would the best arrangement be to have the four foot section at the bow? Interested.

 

It seems you have a preference for planing ; ie a scow design.
-For simplicity sake the bottom would be limited to a 4x8 sheet of plywood. Since the whole game is getting on plane and staying on plane I think it best to put it in the rules.

-When it comes to rig your primary limitation is 4.3M mast height if you don't go to 2pc. It seems your dissatisfaction with the bug is that it is small, and what you want is a small boat that sails big. 6.5 SM is the size of the spiral sail -but you don't have the mast length of a spiral. A 4.3M mast would have about 3.3M luff so it would need to be square top to get to the maximum on a ~2M boom. Before you rule out the 2 pc mast, why not try a spiral rig on a bug and see what you think?

Your dimensional limits are based on a parking space, but you don't consider diagonals? An 8ft wide by 8ft high space would fit an 11ft hull on the diagonal with narrow ends. A solid mast could be 4.9M. With a removable bow sprit that might make a proper skiff.

This thread looks to me like a rehash of Petro's hardware store development class. You don't admit it, but you are more 'budget' than 'open'. I suggest you use Petro's HS rule as a boilerplate and read the blog when you wonder why. For an open class dingy on a budget, that's as good as it gets.

 

Hoyt; the bow section takes more beating than the aft section. So it seems logical to place the joint nearer the stern. Also there is a lot of twisting and racking of the forward sections when they are exposed to the forces of the mast.

The two foot extension attached to an eight foot foreward section is only a small lever. Actually the aft section contains only a small portion of the total displaced volume of the boat. In fact the transom is likely to be above the waterline. A boat that I have on my drawing board is ten feet long. It has a joint at the 8 foot section. The aft two foot section has a normal displacement of less than 700 cubic inches for an upload of about 25 pounds.

We can anticipate a much larger load on the coupling because of waves and wakes that would momentarily influence the displacement on the aft section. Worst case scenario would be a beach landing in a breaking surf. The near verticle face of the breaker could increase the load of the aft bit considerably but not beyond the capability of the couplings.

To reduce the potential for high loads, the aft section could have a deck that is tapered sharply downward from the sheer at the coupling to somewhere near the waterline. The four bolts that hold the thing together are 8mm class eight cap screws. The boat itself will fail before the joiners do. The cone shaped joiner hardware makes alignment easy when assembling. I have in mind a short lanyard fastened to the middle of the aft section bulkhead. It will lead forward to a cleat so that the tightened lanyard will hold the parts together while you attach the bolts and nuts. SImple, quick, effective, storable in my garage.

 

That sounds like a good way to do it.

 

WD, maybe you can look back, the Manly Junior was created around a similar storage issue, there's plenty of them & an adult if nimble(you will need to be on an 8 footer) you can fit under the boom etc, can make for exciting sailing one up, I have taken the MJ my boys had out in 35-40 & had a ball until I dropped the stick, great fun setting the hanky kite one up too, maybe a turbo model with some extra area & assy might be the go.
Another contender might be the Vaucluse Junior, even with a removable bow, though there's plenty of these been hung up from the garage roof. Just sayin' these issues have been dealt with in history & might come at a much lower entry level with existing boats in the market, you'll be keeping history alive too.......

Jeff

 

Reply to Waikikin

Thank you for your suggestion.

The Manly Junior is 2.6 metres or 8ft 8inches. Too long to meet the requirement of standing on its transom in an underground carpark. It was designed in 1959. The Vaucluse Junior "VJ" is a realatively high performance boat with two sliding seats and a length of 11.5 feet. It was designed in the 30s. A "take apart" knock-off would not be competitive with existing class boats. Can we do better, after more than 50 years?

Respectfully, keeping history alive, has it's place, but we are trying to create something new.

 

Reply to Skyak

Our club races dinghies and few modern dinghies will not plane, we feel there is an imperative to have planing performance.

The PDRacer mentioned on the first page of this thread, comes close to creating the maximum planing surface from one sheet of ply. I had a bad experience with one, but their popularity appears to put me in a minority.

The Firebug is also a scow but with more shape than the PDR, but we are absolutely open to skiffs, just so long as they are 8 footers. Scow are, on the whole, better load carriers, so a scow may suit a wider range of weights, but that is up to the designers. Also, hydrodynamically, the scow appears to offer advantages on such the short hull, but it is acutely sensitive to trim.

The mast length is certainly in the "to be determined" category, but one factor determining its length, will be the decision whether it should be deck stepped and stayed (Firebug), or through to the keel in a tube, like the Spiral or the PDR (that I have seen). Probably the key dimension here is the position of the gooseneck above the deck.

I note your comments about diagonals, but put simply, our intention is to hold an 8 footer regatta, not to define a rule based on the theoretical dimensions of the back wall of a unit garage. I see no objection to a bowsprit, or a foretriangle, JRD kindly posted a photo of an 8 ft Skiff above, but remember, if the weight of the rig is forward, the risk of a nosedive is increased, and short boats have that tendency to a greater or lesser degree.

You are absolutely correct regarding Petro's thread, I posted to it initially. Petros has done a terrific job in pulling together the rules. I hope he gets many boats built. The core difference is that we are looking at a much smaller craft, dictated by the particular circumstances of our club.

Clearly, you have thought about this issue a great deal, we would be delighted if you would submit a design, but within the non-negotiable parameter of a maximum hull length of 8 foot.

Remember the adage, "the smaller the boat, the greater the fun."

 

Weight is about 64lbs from exterior plywood - no need for expensive gaboon, but the secret, like any boat, is getting all the bits just right.



http://www.youtube.com/watch?v=B3f7n1IWozg

I would strongly recommend not framing out rules for weights or sail areas or construction until after either seeing or sailing adult boats of this size. It is new territory for most.

A good idea would be to have an open rule so limits of hull weight, sail area, construction can be discovered. Otherwise the boat might be so much less than it could be.

For those suggesting weights around the 90lb mark ... why not see if basic materials can produce something much lighter (evidence above is they can - scores launched and durable) or those suggesting sail area limits ... how much can an adult on a four foot beam (or more boat) hold up easily? If you choose 65 square feet you might be unnecessarily hampering the boat.

Keep it open and find out what can be achieved. The idea of a rule for 8ft boats is very nice but don't restrict it at an early stage without data on real boats. And the best place for that ... is on the water.

Best wishes
Michael Storer