Possible Class of Small Ocean Racing Sail boat

[sharpii2]

Hi sharpii2, I too have thought about a new class, much smaller than yours, to race home built versions of the Elusion and similar overpriced single handed micro yachts, inshore only, all abilities. While possibly irrelevant, I'll post my thoughts on rules and regulations I came up with for the class. I gave up on the idea myself, but if someone wanted to take it up, they're welcome to. It was all about development, and cheap fun. I am a novice, not a class rules lawyer, so it is crude and clunky, but may give you something else to consider in your proposed class definition or rules.

The DOOR 750
So named because it will fit through a standard household door frame wider than 750 m
One or two person racing sail boat. Beam maximum 750 mm
A developmental class with few restrictions, and simple rules, so as to make inexpensive but safe sailable models of variable design, and have fun. Fit two DOORS on a trailer, side by side.

The boat can be built indoors, in a normal house with a standard door frame exit, in most cases; unless you are married or have a landlord.
Built strong enough to withstand at least 1m swell + 1 m seas + 30 Kn wind, and self righting in knockdowns in those conditions.
Hull shape and design is to be made public if the hull places in the top 5 finishes in any recognised race.

Dimensions
Length Over All is 6 m maximum
Generally as long a hull as you can get from 2 sheets of pywood end on end, scarfed or butted, plus some leftovers.
Prefer 5 m to 4 m long, since not many people have huge spare rooms, but unwieldy extravagance is ok if it's strong enough.
It can be long and sharp, or a more manageable practical length.
It can be a low and sleek, high aspect design, or it can be high sided with a cabin and flybridge, if you can work it.

Hull
Very simple shapes without torturing the plywood into compound curves.
Slab sides, and bottom, made of any plywood like, flat, flexible, similar behaving material.
Flat bottomed abeam front to back, with rocker and bottom contours fore and aft, made from 1 + 1 sheets of plywood end on end, with almost no bottom V angle, or slightly curved from flat, but warped un-cut plywood.
Sides with small angle to vertical, outward, or tumblehome, hard single chine < r 50 mm.
Sealed buoyancy tanks must be able to support a water filled yacht in an upright attitude, still with 8 inches of freeboard, to allow effective bailing out of water in rough conditions.
Steel centreboards can rotate to lift; or fixed shoal draft keels; or twin keels, may be used, all for easy trailering and storage, and fun in shallow waters. No 'deep keels'.
Any shape of monohull which can be produced from flat bendable panels.
Brackets for motors are allowed, and internal outboard motor wells.
A thick bottom thickness to take groundings at speed, and give stiffness (say 8 mm min); minimum 5mm thick ply or substitute of equal strength, everywhere else.

Mass
There will be a minimum weight eventually, based on the weight of an average plywood and metal build; but any materials can be used anywhere, if it is safe and durable.
Heavy ballast may be used, in any manner, within the rules, as long as still buoyant when swamped.
Water ballast may be used, but no side ballast tank pumping allowed. Keeping it simple.

Rig
Any that you have on hand, whichever works, is versatile and reliable, and copes with more than 30 Kn wind and knockdowns.
Whatever you have from other yachts that you can use, or adapt, or weave a crabclaw, or invent something - no shape is specified.
Un-stayed, or stays, or other, no mast restrictions, to support any design of fabric sails.
Only fabric type sails allowed, no metals, wings, rotors, or other contrivances.
Try to make it look a bit like some sort of big yacht, from a distance.

Rowable, or able to be paddled effectively and usefully for safety, like a canoe.
Simple light weight stitch and glue, or framed construction; framing in any material.
Cockpits can be placed anywhere, and two people are allowed, one behind the other, kayak style, or side by side if extremely emaciated. Gimballed seating is allowed, to sit upright.
Steering can be via foot pedals or wheel or levers or tiller, to inboard or stern mounted rudders.
Motors must be removed or stowed if / when racing; batteries can remain in place.

Or (My favourite) a Door 750 on wheels, to hand launch when I'm old and can't drive cars anymore.

ROLLER DOOR 750
Twin keels with steel, or water filled wheels, so it can be manoevred on land by hand.
Thinking weighted plane landing wheels, tough, broad, smooth, possibly roll on sand.

Steel frame holds keels, internal legs, and axles; sets chine width; can extend keels fore and aft.
Slab sides - 2 deg more angle than eg. a Heron
freeboard 1 - 2 inch more than eg. a Heron
long raked bow or square.

My idea didn't get much attention, and I didn't think too hard about it, but I thought restricting materials to hardware store marine ply and polyester resin, and flat panels with limited compound curves, would keep a 'level playing field' as far as folks with an unlimited budget goes. Reminding me of the 'hardware store sail boat' thread somewhere here.

Good luck with your class, a fleet of affordable pocket global racers that can also possibly be cruisers, sounds great. Maybe even small enough to trailer.

I like your general idea.

But I see problems with a Beam of less than 3 ft (0.91 m). When considering the sitting ht of the typical adult, this could create significant initial stability issues. These issues would have to be solved by:

1.) a good amount of dense internal ballast (lead blocks), or
2.) external ballast.

With no draft limit, the faster boats are going to end up with deep, bulbed keels. Not limiting the sail area will also push the class in this direction.
Being able to get the hull out through a typical house door would be meaninless if the empty boat weighs several hundred pounds, and was so tall that it would be difficult to carry. This is the reason why, in my proposed class, I limited the draft. Limiting the ballast specific gravity would be a further improvement in this direction. Suppose you limited the draft to say 2/3 the Beam, or 500 mm. The boat would still be heavy, but two or three strong men would be able to carry it out of a house. If the specitfic gravity of the external ballast were limited to say 3.0, this would put a real limit on keel design. Bulbs would not be practical, and greater ballast to displacement ratios would also mean greater whetted area. To have a monster rig would mean having a very long, monstr keel. Swing keels and drop keels would be pretty much ruled out too. I think it is also a good idea to keep the builders out of the lead smelting business. Such a limitaion would make a grp incased concrete keel a practical option.

I think your length limit is far too generous. In this set of restrictions, longer boats would have the overwhelming advantage. I think 5 m is a far more realistic limit. Then the boat could be built in a typical garage (and stored there too). It could also be built inside a house, if it had a removable bow or stern section. But you better believe that whatever length limit you choose will be the length of the competitive boats in the class.

You will also need a rule against hiking out to keep this from becoming a athletic competition. Such a prohibition would definitely limit the sail area and perhaps the rig ht as well (as much as the external ballast specific gravity would) and may also help make sail types and rigs, that typically aren't seen as racing ones, competitive.

To keep the competition reasonably fair, I think you will need a minimum boat + crew mass limit of no less than say 400 kg (about 200 kg for the boat and about 200 kg for the crew). Short falls of this minimum can be made up with inside water ballast. This way, two crew and one crew boats could compete with one another. A sail area of around 11 sm would move a boat of this mass nicely.

Part of my initial intent was to create a class where the boats would be:
1.) less extreme in ability to sail competitively and less extreme in cost to to be competitive,
2.) useful for activities other than racing, and
3.) keep the "thous" and "thou shalt nots" down to a minimum by mandating strategic design limits.

Your limiting the Beam is an excellent example of one.

As much as I like the idea of a roller version one, I don't think it would be something you would be able to handle in old age. If you increased the Beam to say 1,000 mm, it may no longer need ballast and could therfore be lighter. Making wheels wide enough to roll on sand may not be practical. I think it would be far more entertaining to have the wheels double as twin keels. They would then work on just about any kind of pavement, such as a boat ramp.

You could still stipulate that the hull should be able to fit through a typical house doorway, but it would have to be on its side.

I am working on rules for a class of 0.91 m Beam scow skiffs that can be of different lengths, displacements, and sail areas, but can still race as equals. I am doing this mainly as an intellectual challenge.

 

[sharpii2]

My input to Sharpii2 is that your rules are a far short of defining a performance envelope. If a good velocity prediction program is V(l,w,h,m,....) then a good rule is fixing a couple variables and setting the whole thing equal to a reasonably high constant.

I too would like to see a class like the 2.4M but much much cheaper and easier to deploy and campaign. Replace the hundreds of pounds of lead in the fat keel with a bulb on a deep dagger and make the rig a main up with a symmetric spinnaker down.

The "hardware store" thread is New low-cost "hardware store" racing class; input on proposed rules | Boat Design Net
We really covered about everything possible for dingies.
Some good ideas that didn't get used:
-standardize parts that use uncommon manufacture and are unlikely to display major positive innovation. A laser rig and training (uncert) sail is cheap and hard to beat.
-rotate which parts are standard to open innovation in alternate seasons
-gain versatility by having a diverse season of competition -windward leeward, triangle or other shape, point to point, carry extra crew, start race with boats still strapped to roof of car 50m from the beach, race out to find a MOB dummy with only last known coordinates....

I think you have the ideas for a good salvaged Laser rig class.

The laser rig itself will really limit the design possibilities. This would make other restrictions, other than hull weight minimums, draft maximums, and perhaps hull length maximums, pretty much unneccessary. I would dispense with the downwind sail though.

 

[sharpii2]

It seems like we are kicking around several ideas here.

With so many sailboats, it is hard to get a new class off the ground.

All sailing classes end up being a combination of the following things (let me know what I missed):
1. A sailing competition. One-design boats, theoretically.
1B. A body size/shape + sailing competition. One-design boats, at least in the Olympic dinghy classes...
2. A design competition. Development classes, theoretically.
2B. A spending competition. Development classes, realistically.
3. A used boat shopping competition (Will Gilmore's proposed class)
4. A whining-about-rating competition. PHRF.

So, whenever proposing a class, we should have in mind what kind of competition we are trying to create.

Of these four choices, I prefer choice #4. But I think choice #2 is viable with the right strategic design limitations. There are a limited number of design elements that make for a fast sailboat. I think they can be summed up with the following formula:

Speed = ((innitial stability) * (sail efficiency>1.0 * 0.25)/mass) - drag.

A flat-cut sail (and flat setting), for instance, would rate a 1.0. A super well shaped sail would rate a likely 2.0, so it would arguably be about 25% faster, if everything else were equal. Such sails are often a high component of the cost. So, certain short-lived, expensive technologies should probably be banned unless specifically permitted.

I think a good class design rule anticipates likely consequences of its choices.

Box rules, for instance tend to create boxy hulls. This is because average Beam can actually beat extreme Beam, if the average Beam of the narrower hull is greater than the average Beam of the beamier hull. So, if I limit Beam, I can expect to have winning boats having pencil-like top views, or even box-like ones.

Limiting draft can push ballast/displacement ratios way up on keel boats, unless those too are limited, directly or indirectly. If that is done, rig heights, in relation to sail area will be pretty much limited automatically.

limmiting sail area will likely bring about hulls that are as long and light as possible, so length limits of some kind are needed. If a hard-fast one is set, then all the compettitive boats in that class will be that length. Indirect limits on length are those that force trade-offs. One of which (the old 12 meter class) traded greater length for less sail area. Another possible trade-off is length against draft. Then the longer boats would be faster down wind, but slower upwind.

Trading rig height against greater length is an option I don't think has ever been tried. Such could have very instructive consequences. Longer boats with shorter rigs could well beat shorter boats with taller rigs, if all the sail area (including the down wind sail area) were equal. Even if this is so, a ridiculously long boat would end up with a ridiculously short rig. The shorter boat with the taller rig would likely be beamier. So, under these conditions, The boat lengths would probably be within 25% of one another. The easiest way to impose such a trade-off is to have a sum of the two combined.

This is my latest ammendment.

I now stipulate a 12 m sum of boat length plus rig height.

Now, the sail area is fixed, the draft is fixed, but the boat length and rig height are variably limited. More of one means less of another.

Other stipulations are added as well to limit more extreme design options within these four main design limitations.

 

[Will Gilmore]

3. A used boat shopping competition (Will Gilmore's proposed class)

Of course, simply stated, as I had, it might become a used boat competition, but my idea was to address the problem of rising construction costs that competitions like the America's Cup and (Whitbread) Ocean Race have suffered from. Only the super rich or corporate sponsored can compete.

The intent is to limit the value of the boat to that which can be built by anyone with a reasonable sailing budget. New design tech versus old, used boat, may not be a reasonable entry. However, if the entrant must meet a budget based upon the value of the materials, that is, can anyone have the entering boat built for the restricted price, then the only way to beat the competition is through innovation in design.

With no draft limit, the faster boats are going to end up with deep, bulbed keels. Not limiting the sail area will also push the class in this direction.

longer boats would have the overwhelming advantage.

You will also need a rule against hiking out to keep this from becoming a athletic competition.

Part of my initial intent was to create a class where the boats would be:
1.) less extreme in ability to sail competitively and less extreme in cost to to be competitive,
2.) useful for activities other than racing, and
3.) keep the "thous" and "thou shalt nots" down to a minimum by mandating strategic design limits.

I think it is hard to not get lost in a lot of specification rules to address some abstract concept of competition.

If it is to be a sailing competition that makes it easy for anyone to be competitive in a vessel that is restricted from exploiting extremes of advantageous design elements, yet, at the same time, encourage design innovation, the limits have to be broadly stated with the clear intent of their formulation written into them.

Simply restricting draft or sail area or ballast or beam without being clear what the goal is, means it becomes difficult for a race official to make a judgement on an innovation that isn't explicitly addressed.

-Will

 

[griffinb]

We are discussing at least 3 very different budgets:
1. America's Cup budgets
2. "Reasonable sailing budget" (whatever that is)
3. Hardware store budget

Used boats are cheaper than building new boats. So if budget is really a concern, we shouldn't even be talking about building new class of boats. We should be asking "how do we get people excited to spend time sailing all these cheap used boats"?

Kiteboards, sailboards, and now wingfoil boards are all much smaller and more portable than any sailboat. So if the criteria is fitting the boat through the door of your apartment, forget about boats, and switch to boards.

The other unspoken truth here is that people love different aspects of sailboat racing:
1. Actually sailing
2. Messing with boats (tuning)
3. Building boats
4. Designing boats
5. Thinking & arguing about designing boats

I only race a few days per year, so I'm definitely guilty of #5, and it feels like we are all operating pretty far down that spectrum...

The other truth is that even if we achieved the creation of a new development class, and convinced a bunch of people to join us, then eventually the designs coalesce around a few winning ideas, the boats all start to look and perform similarly. So then skill/athleticism/body-size take over ask the winning factors. Look at the history of the Moth development class (before they all started foiling). Basically, this entire discussion is about "how can we go back to the beginning of the Moth class, and go through that whole development process again?"

 

[CT249]

Of these four choices, I prefer choice #4. But I think choice #2 is viable with the right strategic design limitations. There are a limited number of design elements that make for a fast sailboat. I think they can be summed up with the following formula:

Speed = ((innitial stability) * (sail efficiency>1.0 * 0.25)/mass) - drag.

A flat-cut sail (and flat setting), for instance, would rate a 1.0. A super well shaped sail would rate a likely 2.0, so it would arguably be about 25% faster, if everything else were equal. Such sails are often a high component of the cost. So, certain short-lived, expensive technologies should probably be banned unless specifically permitted.

I think a good class design rule anticipates likely consequences of its choices.

Box rules, for instance tend to create boxy hulls. This is because average Beam can actually beat extreme Beam, if the average Beam of the narrower hull is greater than the average Beam of the beamier hull. So, if I limit Beam, I can expect to have winning boats having pencil-like top views, or even box-like ones.

Limiting draft can push ballast/displacement ratios way up on keel boats, unless those too are limited, directly or indirectly. If that is done, rig heights, in relation to sail area will be pretty much limited automatically.

limmiting sail area will likely bring about hulls that are as long and light as possible, so length limits of some kind are needed. If a hard-fast one is set, then all the compettitive boats in that class will be that length. Indirect limits on length are those that force trade-offs. One of which (the old 12 meter class) traded greater length for less sail area. Another possible trade-off is length against draft. Then the longer boats would be faster down wind, but slower upwind.

In dinghies there seems to be no innate tendency for box rules to create boxy hulls. Look again at Moths - the narrow skiffs had a waterline beam of just 300mm (1ft). In classes like 16 Foot Skiffs and 18s there was a very strong move to much slimmer hulls as rig technology allowed the development of lighter rigs.

Some "box rule" dinghies are chunky in some ways but that is almost entirely due to them having vast rigs or high crew weight (12 Foot Skiffs, although their waterline shape isn't fat) or other rule requirements (ie Cherubs, Merlin Rockets which have very wide gunwale beam but very narrow waterline beam).

Trading rig height against greater length is an option I don't think has ever been tried. Such could have very instructive consequences. Longer boats with shorter rigs could well beat shorter boats with taller rigs, if all the sail area (including the down wind sail area) were equal. Even if this is so, a ridiculously long boat would end up with a ridiculously short rig. The shorter boat with the taller rig would likely be beamier. So, under these conditions, The boat lengths would probably be within 25% of one another. The easiest way to impose such a trade-off is to have a sum of the two combined.

This is my latest ammendment.

I now stipulate a 12 m sum of boat length plus rig height.

Now, the sail area is fixed, the draft is fixed, but the boat length and rig height are variably limited. More of one means less of another.

Other stipulations are added as well to limit more extreme design options within these four main design limitations.

There's no way that a "super well cut sail" is 25% faster than a "flat cut" sail, as actual experience will show. There's a surprising amount of good sails that you can trim to have very little depth (in the case of a windsurfer sail you can actually have negative camber) and there is no way in the world that such a sail, set flat, is 25% slower than a sail of optimal shape. Heck, in light winds you can get many sails with negative camber (by not making sure full battens "pop" after tacking) and that doesn't slow you down 25%.

If you mean form stability by the term "Initial stability", then it has nothing really significant to do with dinghy speed, as the simplest look at fast dinghies will show one. Perhaps the best check can be seen in Moths; a narrow skiff has negative form stability and is the fastest non-foiling Moth. A "fat skiff" (early Magnum type) has a bit more form stability but probably negative real form stability, whereas a late scow has heaps of form stability - and is about as fast as a Magnum depending on wind speed. A really old US style skiff has far less stability than a late scow, but is slower.

Similarly, there's plenty of two-person boats that are similar in speed and length to an IC although the inherent stability of the two types is dramatically different.

 

[sharpii2]

There's no way that a "super well cut sail" is 25% faster than a "flat cut" sail, as actual experience will show. There's a surprising amount of good sails that you can trim to have very little depth (in the case of a windsurfer sail you can actually have negative camber) and there is no way in the world that such a sail, set flat, is 25% slower than a sail of optimal shape. Heck, in light winds you can get many sails with negative camber (by not making sure full battens "pop" after tacking) and that doesn't slow you down 25%.

If you mean form stability by the term "Initial stability", then it has nothing really significant to do with dinghy speed, as the simplest look at fast dinghies will show one. Perhaps the best check can be seen in Moths; a narrow skiff has negative form stability and is the fastest non-foiling Moth. A "fat skiff" (early Magnum type) has a bit more form stability but probably negative real form stability, whereas a late scow has heaps of form stability - and is about as fast as a Magnum depending on wind speed. A really old US style skiff has far less stability than a late scow, but is slower.

Similarly, there's plenty of two-person boats that are similar in speed and length to an IC although the inherent stability of the two types is dramatically different.

CT. I may have been unclear on what I mean by "initial stability".

What I mean is the stability of a boat at small angles of heel.

There are atleast three ways to achieve high initial stability:
1.) Have a relatively wide waterline Beam,
2.) Have shifting ballast that extends even past the boat's maximum Beam, and
3.) Have a narrow waterline Beam with outward flailing hull above it.

If we were to include the crews bodies into the Moth's Beam, even just to their centers of mass, the Moth would be quite beamy indeed.

This was why I used the term "initial stability" instead of "form stability".

When it comes to keel boats, where the crew is a small fraction of the total weight, as in a single-handed ocean racer, hiking out is not so effective.

What I have noticed is that, with higher ballast/displacement ratios, it is often best to have a relatively narrow waterline Beam, but a greater over all Beam.

This way, in light winds, the boat behaves as if it is narrower than it actually is. When it breezes up, the boat heels over some, putting the wider part of the hull into the water, increasing its form stability. This design strategy works best when the sail area per displacement is somewhat modest.

As for hiking out on dinghies, I think it should be banned except for when it is originally intended. Such can be great fun, and it allows the boat to go much faster. There are lots of dinghy classes out there that allow this. I would not want to add to them. Instead I'd rather offer an alternative.

As for my comment on sail efficiency. A sail that forms almost a perfect airfoil section is far superior to one that doesn't, even though there are times that it is best to flatten this sail out. It sure beats reefing. It is quicker and almost as effective. Just tug on a few lines and the job is done. Or it even flattens automatically, as the higher sheet tensions bend the boom and mast, pulling the sail membrane flatter.

But in more moderate conditions, the airfoil sectional shape is indispensable for getting the optimal performance per given sail area. I think you would agree.

I have even thought of the idea of allowing boats with flat setting sails to have 25% more sail area than the boats that don't. But then I considered the likely abuses. One would be to put tension loops in strategic locations along the luff which could cause the once flat sail to form a curved section, once tightened. By putting in battens, that extend inward from the leach, it may well be possible to cause to cause this curve to form a more or less airfoil shape. Such devises would also have to be banned, lest they defeat the whole purpose of allowing larger flat-setting sails.

I am probably wrong in saying that a sail that forms a more or less perfect airfoil shape is 25% faster than a flat setting one. My figure is really a guess. The truth is likely that it adds maybe the square root of that to average boat speed. But I think we can both agree that even a 5% advantage, if it is consistent, can pretty much make a boat a perennial champion.

 

[seasquirt]

Keep at it sharpii2, I think your idea could be popular and work. There's no chance that a group of sailors could agree on a single existing yacht type to take up, and maybe modify minimally to suit the new rules. And even if a quorum did agree on one hull that did fit the rules, there probably quickly wouldn't be enough hulls to go around, the molds would already be old and possibly already modified (if glass); different build groups and batches; diff materials and thicknesses / weights, so inconsistencies and arguments. If the chosen hull wasn't already popular and in demand, thus an exceptionally good one, why bother with it anyway.

Start anew, with given dimensions, tolerances, and objectives, and mess about until someone finds the most sweet spots with their interpretations of the rules, and keeps winning. Spending caps will never work - it's a race ! : "My brother inlaw sold me it cheap for this much"! Workmanship, materials, care, and safety may suffer if one has to sell their winning boat at the end of the race; rescue boats recommended.
I like the idea of a 50 L / 50 KG bag of water to replace the crew, easy to get along with, and does what is expected.
Things I'd be interested in: Water filled centreboards are good I think, for trailerability, and long shallow lifting centreboards for shallow waters. I know u don't want c'boards, but not everywhere has a deep boat ramp. A cozy cabin minimum size like a 4 man tent = big enough for 2 in reality; family sized would be better. Able to take a regular short leg outboard. Light and small enough with all gear to not need a breakaway trailer, or any permits, or signs, or night restrictions. Amenable to all manner of accessories, like autohelm, mast top aerials, solar panels, anchor winch, cooler and stove, head, etc., to make it useful beyond racing, and still be within whatever the rules are.
Plywood builds would give the easiest hull tweaks, and a glass molded hull might limit hull variability, and allow highly stressed rigs, but also be a production bottleneck. What are your proposed materials / methods so far ? All comers, ply, glass, foam sandwich, steel, ally, ferro cement, rotomolded plastic, 3D welded plastic ? It seems like glass molded is your preferred idea, so far.

 

[sharpii2]

Keep at it sharpii2, I think your idea could be popular and work. There's no chance that a group of sailors could agree on a single existing yacht type to take up, and maybe modify minimally to suit the new rules. And even if a quorum did agree on one hull that did fit the rules, there probably quickly wouldn't be enough hulls to go around, the molds would already be old and possibly already modified (if glass); different build groups and batches; diff materials and thicknesses / weights, so inconsistencies and arguments. If the chosen hull wasn't already popular and in demand, thus an exceptionally good one, why bother with it anyway.

Start anew, with given dimensions, tolerances, and objectives, and mess about until someone finds the most sweet spots with their interpretations of the rules, and keeps winning. Spending caps will never work - it's a race ! : "My brother inlaw sold me it cheap for this much"! Workmanship, materials, care, and safety may suffer if one has to sell their winning boat at the end of the race; rescue boats recommended.
I like the idea of a 50 L / 50 KG bag of water to replace the crew, easy to get along with, and does what is expected.
Things I'd be interested in: Water filled centreboards are good I think, for trailerability, and long shallow lifting centreboards for shallow waters. I know u don't want c'boards, but not everywhere has a deep boat ramp. A cozy cabin minimum size like a 4 man tent = big enough for 2 in reality; family sized would be better. Able to take a regular short leg outboard. Light and small enough with all gear to not need a breakaway trailer, or any permits, or signs, or night restrictions. Amenable to all manner of accessories, like autohelm, mast top aerials, solar panels, anchor winch, cooler and stove, head, etc., to make it useful beyond racing, and still be within whatever the rules are.
Plywood builds would give the easiest hull tweaks, and a glass molded hull might limit hull variability, and allow highly stressed rigs, but also be a production bottleneck. What are your proposed materials / methods so far ? All comers, ply, glass, foam sandwich, steel, ally, ferro cement, rotomolded plastic, 3D welded plastic ? It seems like glass molded is your preferred idea, so far.

Seasquirt.

I think keeping the construction method open is a good idea.

This is as long as it meets the minimum mass per square meter of hull and deck area.

Swing keels, drop keels, and center boards would be allowed, if they stay within the 1 m maximum draft when extended.

One must be careful not to create a one-course class. What I mean by that is a class that is good only going upwind and downwind, for example.

With my new length + sail ht sum stipulation, the boats are not likely to be all that beamy. 2.0 to maybe 2.44 m is likely to be a popular range for beam. Some might go narrower, but I doubt any would go much wider. We're talking only 19 sm of sail area here, plus we're playing hull length against rig ht.

A centerboard hull might have an advantage racing downwind. First, with the board up, it can reduce its
total whetted area. And, second, it can give itself a lee helm at a time when it's most useful.

A disadvantage is that it will likely need:
1.) A greater wl beam, to get the same initial stability, and
2.) It will likely need more ballast to get adequate ultimate stability.

Hopefully, it's advantages and disadvantages, over its fixed keel sisters, will cancel each other out.

The idea of shifting water ballast is far cheaper than that of a canting keel to get higher initial stability. But it comes with safety concerns.

Such ballast can create two somewhat undesirable design consequences:

1.) It could encourage very narrow wl beams plus very wide over-all ones, and
2.) By doing such, it can cause a higher effective center of gravity as well as higher inverted stability.

If allowed, it would have to be carefully regulated, which would add another list of stipulations.

One possible simple one would be that its CG can be no higher than 0.10 beam above the wl. Another would be to limit its mass to say 0.25 times the fixed ballast.

 

[griffinb]

Seasquirt.

I think keeping the construction method open is a good idea.

This is as long as it meets the minimum mass per square meter of hull and deck area.

Swing keels, drop keels, and center boards would be allowed, if they stay within the 1 m maximum draft when extended.

One must be careful not to create a one-course class. What I mean by that is a class that is good only going upwind and downwind, for example.

With my new length + sail ht sum stipulation, the boats are not likely to be all that beamy. 2.0 to maybe 2.44 m is likely to be a popular range for beam. Some might go narrower, but I doubt any would go much wider. We're talking only 19 sm of sail area here, plus we're playing hull length against rig ht.

A centerboard hull might have an advantage racing downwind. First, with the board up, it can reduce its
total whetted area. And, second, it can give itself a lee helm at a time when it's most useful.

A disadvantage is that it will likely need:
1.) A greater wl beam, to get the same initial stability, and
2.) It will likely need more ballast to get adequate ultimate stability.

Hopefully, it's advantages and disadvantages, over its fixed keel sisters, will cancel each other out.

The idea of shifting water ballast is far cheaper than that of a canting keel to get higher initial stability. But it comes with safety concerns.

Such ballast can create two somewhat undesirable design consequences:

1.) It could encourage very narrow wl beams plus very wide over-all ones, and
2.) By doing such, it can cause a higher effective center of gravity as well as higher inverted stability.

If allowed, it would have to be carefully regulated, which would add another list of stipulations.

One possible simple one would be that its CG can be no higher than 0.10 beam above the wl. Another would be to limit its mass to say 0.25 times the fixed ballast.

If you are interested in a development class, single-handed, with water ballast, have you checked out the Mini 6.5, aka the Mini 650, aka the Mini TransAt?
Classe Mini https://www.classemini.com/?langue=en

 

[sharpii2]

If you are interested in a development class, single-handed, with water ballast, have you checked out the Mini 6.5, aka the Mini 650, aka the Mini TransAt?
Classe Mini https://www.classemini.com/?langue=en

My idea is pretty much a reaction to this class. Not to desparage it, but to supplement it. I'm thinking something simpler, more user freindly, and certainly less expensive.
This is why the sail area is limited, in my proposed class, and the maximum draft. Now, I have added a rig height + hull length sum limit to this. The idea is to create a competitiion where the boats look a lot like the ones ordinary people are likely to own. I feel that for generations tall rigs have dominated racing. This is for good reason. Taller rigs go to windward better. They also allow larger downwind sails.

But rig height and deep draft can be a PIA for ordinary sailing. The masts are harder to set up. And deep draft not only limits where the boat can sail, but also increases the likelyhood of keel strikes, as well as damage from such.

I figured that, since cruising boats tend to imitate racing boats, it might be a good idea to create a class of racing boats that are limited in such a way that that they better reflect the realities of cruising boats. Let's see what the fastest boat within these limits looks like.

In the near future, due to the interest this thread has attracted, I plan on coming up with a preliminary set of rules, including thous and thou shalt nots, complete with expainations of their purposes.

 

[griffinb]

My idea is pretty much a reaction to this class. Not to desparage it, but to supplement it. I'm thinking something simpler, more user freindly, and certainly less expensive.
This is why the sail area is limited, in my proposed class, and the maximum draft. Now, I have added a rig height + hull length sum limit to this. The idea is to create a competitiion where the boats look a lot like the ones ordinary people are likely to own. I feel that for generations tall rigs have dominated racing. This is for good reason. Taller rigs go to windward better. They also allow larger downwind sails.

But rig height and deep draft can be a PIA for ordinary sailing. The masts are harder to set up. And deep draft not only limits where the boat can sail, but also increases the likelyhood of keel strikes, as well as damage from such.

I figured that, since cruising boats tend to imitate racing boats, it might be a good idea to create a class of racing boats that are limited in such a way that that they better reflect the realities of cruising boats. Let's see what the fastest boat within these limits looks like.

In the near future, due to the interest this thread has attracted, I plan on coming up with a preliminary set of rules, including thous and thou shalt nots, complete with expainations of their purposes.

So you want to create a class of less-racy, normal-cruiser type boats? But you don't want them to be one-design? You want to be able to tinker with the design of normal looking boats to try to win the race? Also, you want to keep things affordable...

How is the answer not "PHRF"?

Instead of trying to outsmart the other designer-builder-sailors in this (non-existent) class, you can still tinker as much as you want with normal cruiser looking boats, and try to outsmart the rating committee (which already exists). In the meantime, you'll have plenty of people to race with you.

Is the dream: "I want to win the competition to build the fastest cruiser-looking sailboat, but not spend much money."?
3 possibilities:
1. the cost is not constrained, and the biggest spenders win (fails your affordability dream)
2. the designs are not constrained, and the least-cruiser-y designs win (fails the aesthetic of your dream)
3. the designs AND costs are constrained, but then the designs are already optimized enough that the sailor matters more than the design. (fails the winning-by-design part of your dream)

If you think you can build a cheap, normal-cruiser-looking sailboat that is significantly faster than what's already available on the used market, then do it. Everyone will be impressed enough. You don't need to create a whole new sailboat class.

 

[sharpii2]

So you want to create a class of less-racy, normal-cruiser type boats? But you don't want them to be one-design? You want to be able to tinker with the design of normal looking boats to try to win the race? Also, you want to keep things affordable...

How is the answer not "PHRF"?

Instead of trying to outsmart the other designer-builder-sailors in this (non-existent) class, you can still tinker as much as you want with normal cruiser looking boats, and try to outsmart the rating committee (which already exists). In the meantime, you'll have plenty of people to race with you.

Is the dream: "I want to win the competition to build the fastest cruiser-looking sailboat, but not spend much money."?
3 possibilities:
1. the cost is not constrained, and the biggest spenders win (fails your affordability dream)
2. the designs are not constrained, and the least-cruiser-y designs win (fails the aesthetic of your dream)
3. the designs AND costs are constrained, but then the designs are already optimized enough that the sailor matters more than the design. (fails the winning-by-design part of your dream)

If you think you can build a cheap, normal-cruiser-looking sailboat that is significantly faster than what's already available on the used market, then do it. Everyone will be impressed enough. You don't need to create a whole new sailboat class.

First off, I am doing this as an intellectual challenge only. This proposed class will probably never exist. I certainly will never be able to afford to build a boat for it.

Second, I make no claim that boats built to this proposed rule would be inexpensive. I only say they are likely to be less expensive than the current 6.5 mini class.

Third, I have no idea of how to design a boat to the PHRF. Aren't boats that sail to to this rule rated only after they have been around long enough for their likely performance to be accurately predicted?

Besides, isn't designing to a handicap rule kind of like designing a mule to beat a race horse, by hoping the mule will be faster than the handicap system thinks it is?

If so, I'm not interested. I'm not that smart.

What I am interested in is creating a class that has different constraints than most classes have, and then trying to guess which design solutions will work best within them.

Wouldn't be some fun to come up with a design concept that would do well within this rule?

It could be as simple as an envelope sketch.

 

[griffinb]

PHRF does allow custom boats:
"A Custom or One-Off Boat or a Boat that has been substantially modified is reviewed as initially presented on a case-by-case basis, and handicapped “as Sailed” based on observed performance and other parametric data. It is documented to include configuration, equipment, appointments, and sails that are onboard during the period of observation. Subsequent changes may be treated as a Modified Boat per below. Boats that are new to the area without documented performance data, may benefit with certified weight data. ."
http://offsoundings.org/pdffiles/2021/OSC 2021 PHRF REGULATIONS.pdf

It's true, that PHRF is not a satisfying rule to try to beat, because if you consistently beat it in a custom boat they just adjust your handicap. But if you want to tinker with custom designs for normal-cruiser looking boats, PHRF is the best place to find a race.

Here's a list of cheap, competitive (advantageously-rated) used sailboats to race in PHRF:
16 Cheap PHRF Racing Sailboats https://www.sailingworld.com/sailboats/16-phrf-racers-fit-budget/

I'm all for trying to beat rules. I've spent lots of time dreaming of ways to beat the CRF (Classic Ratings Formula). I just don't see the point of inventing an arbitrary rule, and then thinking of ways to beat it, while still trying to stay within the "normal-looking" box. Some other interesting rules are: fastest trailerable (without a permit) sailboat, and fastest sailboat to fit in a 40' shipping container. Another classic source of design/shopping constraints are mooring/slip length limits, and bridge air draft limits.

If you aren't going to create a real racing class, and aren't going to build a boat, why do you care that it looks like a normal cruiser, or that it is affordable? Dreams shouldn't be constrained by cruising practicalities or budget.

 

[Will Gilmore]

The problem with a PHRF rule for a development class is, as sharpii2 says,

like designing a mule to beat a race horse, by hoping the mule will be faster than the handicap system thinks it is?

If the point is,

to have a wide diversity of design strategies that can all race together with each having at least a reasonable chance of winning

then a handicap rule would not be conducive to this idea.

The one hard rule from the very beginning of the America's Cup, even though it is raced on a limited, and protected course, is that all entrants must sail their boat to the course, from the origin of the competitor's YC or home port.

Most other rules have been implemented as a reaction to past races where a committee saw some unfair advantage. These new restrictions always led to designers designing around the rules, such as the meters of long overhang to get more length in the water under sail while still measuring the limited lwl to meet the rule. The AC has gone from vessels like 'America' to the giant sail areas and deep keels of the J class, to the controversial wing keels, to the Maxi cats, and now to the foiling monohulls. I haven't followed it in the last few decades, but I believe they still have to be sailed to the race from the challenger's port of origin.

This basic rule restricts these vessels in design and construction but not in expense. There is no restriction to the money spent on these boats. The race is all about the boats, but no club is going to put just any sailor in the captain's seat either.

If this new class is to be a development class and accommodate sailors who may not be as athletic, or fit to sail any small ocean capable boat, why not make it an RC class. Require a passenger/captain, but all sail controls are automatic and remote capable, then, take a basic, aesthetically pleasing hull and sail plan, then leave everything else opened?