Boat Design Forums  |  Boat Design Directory  |  Boat Design Gallery  |  Boat Design Book Store  |  Thanks to Our Site Sponsors

Go Back   Boat Design Forums > Design > Sailboats
Register FAQ Members List Calendar Search Today's Posts Mark Forums Read

Reply
 
Thread Tools Search this Thread Display Modes
  #271  
Old 08-09-2012, 08:13 PM
CT 249 CT 249 is offline
Senior Member
 
Join Date: Dec 2004
Rep: 378 Posts: 1,313
Location: Sydney Australia
Quote:
Originally Posted by Owen423 View Post
Here my thoughts on the HardwareStore boat *challenge*... and I'm liking my ideas enough to (almost) want to build the boat...

Rule 1. No mast stays or shrouds

Why not? Stays and shrouds are cheap and effective. Why introduce the construction problems created by trying to maximise the height of an unstayed rig? Why prevent simple tall stayed rigs and instead encourage more complex, complicated and expensive multi-mast rigs, which may be a faster option under these rules (but not under the 'rules' of maximising speed for the dollar, square foot or construction man-hour).

Rule 2. Mast(s) must be stepped within 1 foot of Bow or Transom

Why? Why prevent sloop rigs? Why demand that rigs be placed in the bow, which creates wringing strains on the hull, encourages nosediving, and creates strange C of E issues?

Why demand that another mast be placed right aft where it cannot be sheeted effectively without a bizarre, complex and expensive boomkin?

Rule 3. Build materials - the boat must be built from 1 standard ply-skinned door and 2 8*4 sheets of 3mm plywood and 3 sticks of 1 1/2 by 3/4 clear timber 8 foot long

Sorry, are you saying that a door has to be purchased and then taken apart so that its materials can be used? Why create extra labour?
Rule 4. The boat will have a box-keel that the skipper sits in.


Why?

Why demand that this supposedly simple and cheap boat need to be trailer launched or craned, which must surely be the case with a box keel.

Can these materials stand the strain of a keel?

Define "keel".

Define "box keel"

Define "sits in".

Rule 5. Ballast will be carried on board to bring loading up to 150 kg INCLUDING the weight of the skipper - the ballast will be in the form of cast-iron barbell weights, properly secured - swedish rounding will allow a tolerance of +2 to -3 Kg of the target weight

So I have to go out and buy 75kg of weights that I have no use for?

I have to take the 75kg of weights from the back of my house, out to the car and load them up every time I want to race?

I then have to carry the 75kg from the car to the boat, lean over into the boat, and put it in the bilge?

I then have to spend time to secure the weight.

Depending on hiking rules, after all this I then have to suffer a disadvantage to a heavier skipper who can use his weight more effectively, or to a two-person crew consisting of one person stuck in the box and another trapezing.

Why?



Please note that I have a boat the same size as this, which has been racing hard since 1977, and has a hull weight of 64kg..... is this a dinghy or a steamroller?


Rule 6. The box keel will conform to an NACA profile

Which NACA profile?

What NACA profile will allow a 150kg skipper to "sit inside" in a small boat?

Why a NACA profile? Flat plates are surprisingly effective and vastly cheaper in construction time and money.


Rule 7. All Joints must be properly glassed

Define "properly".

Rule 8. all exposed timber must be epoxied and/ or painted

Why can't I varnish??

Rule 9. No composite or alloy materials to be used in the mast or hull, excepting rule 7

What is wrong with using cheap alloy for space frames etc?

Rule 10. All sails are to be made from Tyvek or equivalent, and sail battens can only be made from high tensile nylon crate packing tape
Rule 11. All sundry components are to be purchased from retail outlets, no materials are allowed from Chandlery supplies
Rule 12. All fixed joints on the boat are to be 90 degrees


And thats it. No limits on numbers of masts - or rigging format - so Cat, Ketch, Gaff are allowed - mast height without stays and shrouds will limit ultimate mast length, but no area limits on sails - clipper is a possibility, as is a big no.1 chute for the clinically inclined.

What is a "clipper" sail or rig?


Straight plastic is allowed, and I envisage alot of PVC used - curtain track for sail track, pipe fittings for rudder bushings etc etc.

So why not alloy too?

How the materials are used will be challenging - as it will ostensibly be a U section boat - single or multi - but those material limits will impinge nastily on multi's.. Yes, you could build a naca canoe with sails... but right now I have a *flat cat* pencilled out that would work in the rules... and thats what these suggestions are about - providing a material boundary to provide low cost sailing that is easily built in a garage, without lots of technical difficulties, with lots of scope for variety.

Contests will be scored on appearance, ease of use and a slalom course - windward-leeward... so straight liners would live their lives in penalty...

Just my thoughts

Owen
Who judges appearance? Sounds like an easy way for judges to simply make sure that the boat and person they don't like is the winner, and a recipe for bias.

Who can score a contest on "ease of use"? "Ease" in what way? "Use" by who?

There's nothing in these rules that would stop someone building a low-tech and short-lasting old-style International Canoe. It would be costly, fragile, evil-handling, dangerous and slow compared to what other rules could create, but it would probably have little difficulty winning every race.

There is a vast amount of information about rule development out there if one wants to research, and one also learns a lot when you actually do it. The US sailing scene is very OD focussed so these lessons may not be as well known there. The big lesson (IMHO) is that rule makers (and those agitating for changes) have to respect those who have different opinions, or else any discussion becomes ugly and classes suffer. They should also try to keep discussions fact based. Implying that anyone who differs from you suffers from a defect of the imagination is not a good way to set up a rule set.

Development class dinghies are popular in some places. We already know what makes an effective set of rules and what rules have to cover. Completely ignoring 100+ years of work by hundreds of intelligent knowledgeable people, steeped in sailing cultures and often qualified formally and as champion sailors, is not a great way to create great rules. It's a bit odd that almost everyone on this thread is effectively saying to the many people who have been involved in the creation of many great classes "you have nothing to teach us" by their refusal to research other rules.
Reply With Quote
  #272  
Old 08-10-2012, 01:35 AM
Owen423 Owen423 is offline
Junior Member
 
Join Date: Aug 2012
Rep: 10 Posts: 5
Location: City of Sail
I've a huge respect for what is trying to be achieved on this thread, having read all of it - and the desire to create effectively a 'garage class' - but in doing so, please remember that I am that pop in the garage - my children (and I), periodically have absurd ideas and would like to enjoy a *class* that has design variety, but most of all, the build and materials are accessible (a sailing soapbox-derby if you like)

In my book, inexpensive and hardware store would be *just the ticket* for pop&son built in a garage affair - hence my straw man of rules. It was intended as an exercise in the socratic method, on the basis that yes, 90% of the population could get those materials from a hardware store, and build some kind of craft inexpensively that thanks to some simple rules wouldn't fall apart on the water first time out, and had half a chance of actually sailing (even if it was at 1/4 Knot).

Like all sets of rules, mine contained absurdities, but what I tried to do was focus less on the craft, and more on the source. The focus was deliberately on the amount of key materials and more importantly that pop in the garage who's son has had the latest brainchild for the series and is desperate to try it out. (for example the trimaran that is being developed for trans-oceanic rowing, that is a new swept shape)

Quote:
Development class dinghies are popular in some places. We already know what makes an effective set of rules and what rules have to cover.
Yup, there are lots of dinghy classes - and to be competitive, they tend to be compromised by those very rules - because to win, measures have to be taken that maximise the potential of the craft through the minutiae, either One Design (Laser, Opti) or experimental like the modern Moth class - what the vast majority of rulings cover is maintenance of a boat 'form' - a great example of which are the square meter classes. Rules also target restrictions on 'features' that are seen to have a performance connotation - Vangs, adjustable stays, movable mast steps and more...

Quote:
There is a vast amount of information about rule development out there if one wants to research, and one also learns a lot when you actually do it.
indeed there is - and in almost all cases, they pertain to the intention aimed at, here that is an inexpensive hardware store materials source.

Like all sets of rules, my straw man contained absurdities, but what I tried to do was focus less on the craft. The focus was deliberately on the amount of key materials, their type and more importantly anticipate the skills that pop in the garage who's son has had the latest brainchild for the series and is desperate to try it out, against his mate's and their dad's garage efforts.

Quote:
The big lesson (IMHO) is that rule makers... have to respect those who have different opinions, or else any discussion becomes ugly and classes suffer. They should also try to keep discussions fact based.
I couldn't agree more. I only sought to provoke a discussion on the rules as currently proposed, in relation to stated original intent - that of a low cost hardware store racing class, with hull form(s) and obvious design variety not enjoyed other classes.

But by implication the *We already know what makes an effective set of rules*, and *one also learns a lot when you actually do it.* is surely the academic equivalent of imagining a brick - a fair shot, as I've deliberately played the fool, but I most certainly meant no offence by my comments, and hope that none was taken.

However, no-one actually asked *Why*, I posted my straw man.

I want the whole process to be fun, and creative.

Heck, the racing could even be side by side booths, a pile of materials, a few tools and a marked course. Standing grandprix start - first round the marks in the the boat that they've just built wins - open teams fixed price of entry that covers material, perfect for boat shows and the like… and every team takes a boat home - Bill of provided materials and range of suggested plans provided on the confirmation of entry perhaps
Reply With Quote
  #273  
Old 08-10-2012, 08:52 AM
CutOnce CutOnce is offline
Senior Member
 
Join Date: Jul 2010
Rep: 331 Posts: 592
Location: Water's Edge
All:

It seems this party has reached that point where the fresh interesting discussion has repeated itself into boredom, many of the participants have gone home to relieve the babysitter and only the very late arrivals have the excited energy to keep CTRL-ALT-DELETE looping the discussion into reboot.

Although I very much hope the original poster (Petros) succeeds and gains traction with a new class of boat that lowers the bar and allows more people to build and sail, I fear from personal experience that reaching critical mass is almost impossible.

A summer's worth of time building has been lost. Prices at building centres have risen (they sure don't go down). Consensus amongst the interested but divergent parties is not neatly coalescing. Petros should just post HIS final class rules and ask Jeff (the moderator) to close the thread from further discussion. Analysis paralysis is a killer.

If I were serious about a concept like this, I'd have long ago been seeking sponsorship (Home Depot, Lowes?) and promotion assistance (National Sailing Associations, Boy/Girl Scouts, Woodenboat, Boatdesign.net, etc.) to get the idea out there to potential participants with a firm goal of the first regatta date and location.

Polls, forums and focus groups are NOT leadership. Sometimes you just have to let people vote by their action to join in or sit out the fun. Two real families building in garages is better progress than a nineteen page forum debate about minutia and details.

Just my thoughts.

--
CutOnce
Reply With Quote
  #274  
Old 08-10-2012, 07:40 PM
upchurchmr upchurchmr is offline
Senior Member
 
Join Date: Feb 2011
Rep: 316 Posts: 896
Location: Ft. Worth, Tx, USA
CutOnce for PRESIDENT!

Petros, get on with it, no matter what you do!
Reply With Quote
  #275  
Old 08-10-2012, 07:46 PM
Petros Petros is offline
Senior Member
 
Join Date: Oct 2007
Rep: 1260 Posts: 1,781
Location: Arlington, WA-USA
not to worry, we will get there. The plan was all along to have the first race in the summer of 2013, and right now everyone is busy with summer activities. I will be posting a proposed final set of rules within the next month or so.

Once we have rules and the kernel of an organization to execute it, I will be looking for sponsorship and sharing the idea with other boat building schools and organizations to see if we can get the contest going at several places around the country.
Reply With Quote
  #276  
Old 08-13-2012, 12:44 PM
sharpii2 sharpii2 is offline
Senior Member
 
Join Date: May 2004
Rep: 503 Posts: 1,135
Location: Michigan, USA
As for cooler size, I suggest 24 x 15w x 16h in inches. I think its better to have a little too much room than not have a quite enough. Especially if the boat changes hands and the cooler doesn't. As I think about this, I find myself designing the boat around the cooler.

I see nothing wrong with a stayed rig. I have sailed fiberglass boats that have been given up for dead and have found that a 3/4 sloop can sail up wind reasonably well with an incredible amount of slop in the rig. A three stay or even a five stay rig, with one pair of shrouds lined up with the mast, can be quickly set up with almost supernatural suddeness, if the shrouds have turnbuckles and the fore stay has a multi part lanyard.

I think stayed rigs are best for wide boats, as wide boats provide ample staying base and usually have greater initial stability, requiring a greater section in an unstayed mast than some might find reasonable.

Narrow boats (without deep, heavy ballast keels) are the opposite. They provide a miserly staying base and usually have less initial stability as well, making a stayed rig impractical as well as unnecessary.

A good way to limit rig height and complexity is to limit set up time and/or have a part of the race where the mast must be lowered then raised again. I think this is a far more practical and defensible limit to rig height and complexity than just about anything else I can think of, other than limity the size of the downwind sail.
__________________
I am highly suspicious of the terms 'perfect' and 'best'. I favor the terms 'inadequate', 'adequate', and 'better', instead, with the first of these closest to being an absolute.
Reply With Quote
  #277  
Old 08-15-2012, 10:27 PM
ancient kayaker ancient kayaker is offline
aka Terry Haines
 
Join Date: Aug 2006
Rep: 2130 Posts: 3,321
Location: Alliston, Ontario, Canada
Quote:
Originally Posted by CutOnce View Post
All:

It seems this party has reached that point where the fresh interesting discussion has repeated itself into boredom . . . Consensus amongst the interested but divergent parties is not neatly coalescing. Petros should just post HIS final class rules and ask Jeff (the moderator) to close the thread from further discussion. . . .
CutOnce
Well, let’s try to liven things up a bit. I like the purpose of this thread but stopped following it a while ago. I think we can still achieve a new and inspiring set of rules yet, we don’t want something that will lead to sterile design results.

Here’s my take on objectives, and comments on some of the rules so far:

A. Limiting costs can handicap high-price regions or result in unsafe boat entries.
B. So can specifying materials like plywood which is not available World-wide.
C. I don’t favor mandating design choices which limit ingenuity.
D. I favor encouraging designs for amateur builders and day use by families.
E. Rules must be expressed so they can be policed simply and effectively.
F. For clarity, let’s have one rule for each aspect’ e.g., material, size etc.
G. I favor monos for the reasons given in post #18.
H. The type of race should favor design over crew skills and strength.
I. The race should be held in a manner that favors family-friendly designs.


Here’s my suggestion for an effective and minimalist rule set - if it seem’s a complete departure from previous approaches, it’s meant to be:

1. Size: hull skin area, excluding any decks shall not exceed xxx square feet.

2. Permitted materials: the boat design must be capable of implementing entirely in wood, plus adhesive, fasteners and rig materials. For design evaluation purposes metals or thermo-plastics in sheet form may be used in wood-poor regions but boat builders are cautioned that the RC has discretion to disqualify any boat deemed given an unfair advantage.

3. Forbidden materials: the use of “High-technology” materials such as composites and extrusions is expressly forbidden (list to be appended).

4. Building: the builder must construct the entire boat from permitted materials including rig.

5. Cargo: during the race each boat carry a removable container of yyy capacity filled with water in a fixed location. Such containers shall start full and shall be emptied at some time during the race but may not be moved during the race for other purposes (this to eliminate water ballast and suchlike)

6. Crew: the crew shall consist of the builder and at most one other person.

7. Launching: at the start of the race the boat shall start in a condition in which it can be transported on or in a car, van or pickup, and be rigged and launched by the crew without aid. All devices used for rigging and launching shall be carried on board during the race.

8. Propulsion: the boat shall carry sails and may carry oars but no other means of propulsion may be used during the race.

9. Safety: crew shall remain inside the boat during the race. Any boat that sinks, capsizes, loses a crew member overboard or is swamped shall be disqualified. The boat must be stopped while bailing.


Note: I did not specifically exclude multis because this can be done effectively by rule #1.
__________________
"Boats are like rabbits; you can have one boat or many, but you can't stop at two" - A. Onassis
Boat designs: "a convoluted collection of discontinuous compromise" - Par
". . . ere the end, some work of noble note, may yet be done . . ." -Tennyson
Dances with Turkeys
Reply With Quote
  #278  
Old 08-18-2012, 12:15 AM
sharpii2 sharpii2 is offline
Senior Member
 
Join Date: May 2004
Rep: 503 Posts: 1,135
Location: Michigan, USA
AK, I like your Rules # 7 and 9 the best.

I have now come to the point where I might have an opportunity to build a boat of my own design. I have been figuring out the cutting layouts for all the parts, trying to put butt joints were they will add strength rather than subtract it.

Once the boat is built and sails successfully, I intend to create a developmental class around it.

Since I know the basic hull type I have in mind and what variances I think should be allowed to create, perhaps, faster (but hopefully not disastrously so) versions of said boat, I think I may well create a credible class.

I think too much design freedom is as bad as or worse than too little. Such opens the door to boats of this class being severely out classed by their competitors. That is no fun.

My goal is to have a situation where some boats will do better than others in certain conditions, but fair worse than those others in different conditions.

One way I thought of doing this is to limit sail area, basing it on the weight of the boat and crew, using a formula that gives a slight S/D advantage to heavier boats. Then, the theory goes, the lighter boats will win in windier conditions and the heavier boats will do well in lighter winds.

Due to the design rules I have in mind, longer boats will also have greater D/L ratios, making the shorter, lighter boats, lower S/D boats more likely to plane than them, when the wind pipes up.

I know this is a 'sum rule' where more of one thing requires less of another, to stay within the class. The more I think of this, the more convinced I am that this is the way to go.

With this 'Hardware Store Class', I can see multi's becoming the best design solution. Especially when low cost speed, ample stowage space (on deck), and general user friendliness are concerned. Without lofty, high aspect ratio rigs, they need not have long set up times. Nor do they necessarily need to be all that Beamy Creating a Beam vs. Length trade off , by having a set sum of Beam plus Length, might give mono's a better chance. This would also help limit the amount of material used in the boat, effectively too.
__________________
I am highly suspicious of the terms 'perfect' and 'best'. I favor the terms 'inadequate', 'adequate', and 'better', instead, with the first of these closest to being an absolute.
Reply With Quote
  #279  
Old 08-18-2012, 11:32 AM
ancient kayaker ancient kayaker is offline
aka Terry Haines
 
Join Date: Aug 2006
Rep: 2130 Posts: 3,321
Location: Alliston, Ontario, Canada
Glad you liked those rules Bob. I wanted to get back to what I saw as the family and first-timer roots of the thread.

I still like the "skin area" limit which gets away from policing material cost and usage. Perhaps a 96 sq ft limit (3 ply sheets) would lead to boats around 15 ft or so with a range of different hull forms allowing experimentation.

Perhaps a sail area limit, if neccessary, of the same amount would be appropriate. We could call it the 96/96 class!

I thought there might have been more comment by now but perhaps the thread is getting too old and has lost most of its subscribers.
__________________
"Boats are like rabbits; you can have one boat or many, but you can't stop at two" - A. Onassis
Boat designs: "a convoluted collection of discontinuous compromise" - Par
". . . ere the end, some work of noble note, may yet be done . . ." -Tennyson
Dances with Turkeys
Reply With Quote
  #280  
Old 08-18-2012, 01:33 PM
sharpii2 sharpii2 is offline
Senior Member
 
Join Date: May 2004
Rep: 503 Posts: 1,135
Location: Michigan, USA
Quote:
Originally Posted by ancient kayaker View Post
Glad you liked those rules Bob. I wanted to get back to what I saw as the family and first-timer roots of the thread.

I still like the "skin area" limit which gets away from policing material cost and usage. Perhaps a 96 sq ft limit (3 ply sheets) would lead to boats around 15 ft or so with a range of different hull forms allowing experimentation.

Perhaps a sail area limit, if neccessary, of the same amount would be appropriate. We could call it the 96/96 class!

I thought there might have been more comment by now but perhaps the thread is getting too old and has lost most of its subscribers.
How do propose to measure 'hull Skin area'? That can be difficult and dicey. Especially if the builder ops for a material other than standardized sheet goods.

Something that might work as well but is a whole lot easier to measure is what I call a 'multiple rule'. It is different than a 'sum rule' in that, instead of adding Length and Beam together to get a sum, length are multiplied by each other to get a product. this would be very easy to check at the race with just a tape measure and a cheap calculator. I think you will find that, for general purposes, it would create results in the same range as you're thinking of.

With a 'hull skin limit rule', I'd be very tempted to design a board boat, which is almost all Beam and Length and has almost no freeboard. If it is decked over, it won't sink, or even take on water. I could then put a low toe rail around it, so, while sitting on the deck, I could claim I'm sitting 'in' the boat.

How about a 90/90 class? Or even a 96/96 class? Easy to check and very difficult to beat. if I went with a multi, I would have to settle for a considerably shorter length than with a mono, which, to stay in compliance with the other rules, especially the 'cargo' one, means I would be stuck with pretty fat, burdensome hulls. A six foot wide by 16ft cat, or single outrigger would be my best option then. I could then be faced with a 5 x 19.2ft sharpi or scow competitor.

I don't like your jettisoning the cargo idea. The whole idea of 'cargo' is that it get from port to port. If I knew I would be jettisoning the cargo in the middle of the race, I would make different design decisions. Also, as the class developed, there would be a temptation to arrange the race so the 'cargo' would be carried up wind, then dumped shortly afterward, or at least before the downwind leg got started.
__________________
I am highly suspicious of the terms 'perfect' and 'best'. I favor the terms 'inadequate', 'adequate', and 'better', instead, with the first of these closest to being an absolute.
Reply With Quote
  #281  
Old 08-18-2012, 06:51 PM
ancient kayaker ancient kayaker is offline
aka Terry Haines
 
Join Date: Aug 2006
Rep: 2130 Posts: 3,321
Location: Alliston, Ontario, Canada
Quote:
Originally Posted by sharpii2 View Post
how do propose to measure 'hull Skin area'? That can be difficult and dicey. Especially if the builder ops for a material other than standardized sheet goods.

Something that might work as well but is a whole lot easier to measure is what I call a 'multiple rule'. It is different than a 'sum rule' in that, instead of adding Length and Beam together to get a sum, length are multiplied by each other to get a product. this would be very easy to check at the race with just a tape measure and a cheap calculator. I think you will find that, for general purposes, it would create results in the same range as you're thinking of . . .
Any reasonable rule could be used, but the stating the limit as area was intended to prevent extreme hulls that try to take advantage of the measuring procedure.


Quote:
Originally Posted by sharpii2 View Post

. . . With a 'hull skin limit rule', I'd be very tempted to design a board boat, which is almost all Beam and Length and has almost no freeboard. If it is decked over, it won't sink, or even take on water. I could then put a low toe rail around it, so, while sitting on the deck, I could claim I'm sitting 'in' the boat . . .
No problem but rule #9 might make it diffcult to handle . . . simpler to put in a tiny cockpit for the crew’s feet. Several designs like that.

Quote:
Originally Posted by sharpii2 View Post
. . . How about a 90/90 class? Or even a 96/96 class? Easy to check and very difficult to beat. if I went with a multi, I would have to settle for a considerably shorter length than with a mono, which, to stay in compliance with the other rules, especially the 'cargo' one, means I would be stuck with pretty fat, burdensome hulls. A six foot wide by 16ft cat, or single outrigger would be my best option then. I could then be faced with a 5 x 19.2ft sharpi or scow competitor . . .
Multis would be banned but as you’ve noticed the area rule makes them uncompetitive anyway.

Quote:
Originally Posted by sharpii2 View Post
. . . I don't like your jettisoning the cargo idea. The whole idea of 'cargo' is that it get from port to port. If I knew I would be jettisoning the cargo in the middle of the race, I would make different design decisions. Also, as the class developed, there would be a temptation to arrange the race so the 'cargo' would be carried up wind, then dumped shortly afterward, or at least before the downwind leg got started.
OK, we’ll call it consumable goods instread of cargo! The point is to ensure there is useful storage space, it can be moved easily and got at while under way, so the container doesn’t become part of the structure or some such useless thing. It also ensures the boat can sail well with and without “cargo” and introduces an interesting tactical decision to the race.

I don’t know if any of the rules sound nicer with the explanations, I didn’t want to bulk up my earlier post too much.
__________________
"Boats are like rabbits; you can have one boat or many, but you can't stop at two" - A. Onassis
Boat designs: "a convoluted collection of discontinuous compromise" - Par
". . . ere the end, some work of noble note, may yet be done . . ." -Tennyson
Dances with Turkeys
Reply With Quote
  #282  
Old 08-19-2012, 11:52 AM
sharpii2 sharpii2 is offline
Senior Member
 
Join Date: May 2004
Rep: 503 Posts: 1,135
Location: Michigan, USA
LENGTH + BEAM vs LENGTH x BEAM

I've been thinking about my ideas of 'sum' and 'multiple' rules, where Beam is played against Length. I did some number crunching to compare the two methods.

For the 'sum' rule, I used Beam + Length = 20ft.

For the 'multiple rule', I used Beam x Length = 64ft.

Both yielded similar results with when I tried them with Beam Length proportions that are relatively common.

These are: 1:2, for multi hulls, 1:3 and 1:4, for most dinghies, and 1:5, for sailing canoes.

Here, I'll show you what I came up with, under the heading of each proportion:

1:2
sum B = 6.67ft, L = 13.3ft
mult. B = 5.66ft, L = 11.3ft
1:3
sum B = 5.00ft, L = 15.0ft
mult. B = 4.62ft, L = 13.9ft
1:4
sum B = 4.00ft, L = 16.0ft
mult. B = 4.00ft, L = 16.0ft
1:5
sum B = 3.33ft, L = 16.7ft
mult. B = 3.58ft, L = 17.9ft

Since the Beam will be measured from extreme outer hull skin to extreme outer hull skin, once the boat is set up, the multi hull is going to have to be significantly shorter than a mono hull with more or less typical proportions. Since the boats will have to carry at least one crew and 200lbs of 'cargo' and they are supposed to cost around $600 to build, I assume their all up weight will be around 600lbs.

With this number in mind, assuming LWL will match LOA, I did a quick comparison of extreme D/L's (Displacement Length Ratios), using just the longest and shortest proportions, to give a rough idea of the implications of both kinds of rule.

1:2
sum D/L = 115
mult D/L = 139
1:5
sum D/L = 58.0
mult. D/L = 35.3

As you can see, the 'multiple' rule produced the most extreme results. For this reason, I think the simpler 'sum' rule would be sufficient. Even with the more moderate 'sum' rule, the D/L of a likely multi would be double that of a sailing canoe, which would negate most of a multi's chief advantage: low D/L combined with awesome sail carrying capability. Now it will be burdened with a D/L that is twice as high as that a sailing canoe.

The sailing canoe would have it's own burden. That would be most likely a mult mast rig. The 'heavy' multi would be better up wind and the 'lighter' canoe would be better reaching and down wind tacking.

The choices and dilemma's offered by this kind of rule give hope for a diversified fleet where members would be free to build the kind of boat they want and still have a decent chance of winning on race day.
__________________
I am highly suspicious of the terms 'perfect' and 'best'. I favor the terms 'inadequate', 'adequate', and 'better', instead, with the first of these closest to being an absolute.
Reply With Quote
  #283  
Old 08-19-2012, 02:11 PM
ancient kayaker ancient kayaker is offline
aka Terry Haines
 
Join Date: Aug 2006
Rep: 2130 Posts: 3,321
Location: Alliston, Ontario, Canada
I see how it works, but it is said that the more complicated the rule, the more loopholes it has. For example, where will the beam be measured? If it is to be maximum beam then multiple measurements must be made to located it, if midships, we may soon be seeing wasp-waisted boats.
__________________
"Boats are like rabbits; you can have one boat or many, but you can't stop at two" - A. Onassis
Boat designs: "a convoluted collection of discontinuous compromise" - Par
". . . ere the end, some work of noble note, may yet be done . . ." -Tennyson
Dances with Turkeys
Reply With Quote
  #284  
Old 08-19-2012, 08:40 PM
CT 249 CT 249 is offline
Senior Member
 
Join Date: Dec 2004
Rep: 378 Posts: 1,313
Location: Sydney Australia
Quote:
Originally Posted by ancient kayaker View Post
Well, let’s try to liven things up a bit. I like the purpose of this thread but stopped following it a while ago. I think we can still achieve a new and inspiring set of rules yet, we don’t want something that will lead to sterile design results.

Here’s my take on objectives, and comments on some of the rules so far:

A. Limiting costs can handicap high-price regions or result in unsafe boat entries.
B. So can specifying materials like plywood which is not available World-wide.
C. I don’t favor mandating design choices which limit ingenuity.
D. I favor encouraging designs for amateur builders and day use by families.

Boats suitable for amateur builders and families are typically yard chine and beamy with small rigs, yet your rule does not require chines or beam, nor limit rig size.

E. Rules must be expressed so they can be policed simply and effectively.
F. For clarity, let’s have one rule for each aspect’ e.g., material, size etc.
G. I favor monos for the reasons given in post #18.
H. The type of race should favor design over crew skills and strength.
I. The race should be held in a manner that favors family-friendly designs.


Here’s my suggestion for an effective and minimalist rule set - if it seem’s a complete departure from previous approaches, it’s meant to be:

1. Size: hull skin area, excluding any decks shall not exceed xxx square feet.

As noted earlier, this favours slender, low-freeboard designs, which are not family friendly and which are extremely demanding on crew skill due to lack of form stability.

2. Permitted materials: the boat design must be capable of implementing entirely in wood, plus adhesive, fasteners and rig materials. For design evaluation purposes metals or thermo-plastics in sheet form may be used in wood-poor regions but boat builders are cautioned that the RC has discretion to disqualify any boat deemed given an unfair advantage.

What sort of boat design cannot be built in wood, adhesive and fasteners? Foiling Moths, champion International Canoes, Tornadoes, winning Formula 16 type cats and successful 18 Foot Skiffs have all been built in wood.

3. Forbidden materials: the use of “High-technology” materials such as composites and extrusions is expressly forbidden (list to be appended).

Doesn't that mean that people cannot use a cheap, tough and simple alloy extrusion for tiller or spars?


4. Building: the builder must construct the entire boat from permitted materials including rig.

5. Cargo: during the race each boat carry a removable container of yyy capacity filled with water in a fixed location. Such containers shall start full and shall be emptied at some time during the race but may not be moved during the race for other purposes (this to eliminate water ballast and suchlike)

6. Crew: the crew shall consist of the builder and at most one other person.

7. Launching: at the start of the race the boat shall start in a condition in which it can be transported on or in a car, van or pickup, and be rigged and launched by the crew without aid. All devices used for rigging and launching shall be carried on board during the race.

I used to sail at a club where a public road separated the boat park from the launching ramp. Sometimes, for some reason some people would tow their small keelboats and trailer sailers down the public road stretch with sails up. Following this precedent, anyone could start with their boat fully rigged.

Requiring launching devices to be carried while racing gives a vast advantage to those with strong crews (i.e. adult men rather than families) who can simply carry the boat down to the water. It also gives a major advantage to those who build light boats. Finally, it gives a big incentive to those who are prepared to damage their boat by dragging it down the beach, compared to those of us who don't want to have to spend the next week repairing gouges and scratches.

So the family man with the strong boat that he wants to keep in nice condition is now at a significant disadvantage to the all-male crew with the fragile boat that they don't mind scratching if need be. This may not be a good thing.


8. Propulsion: the boat shall carry sails and may carry oars but no other means of propulsion may be used during the race.

9. Safety: crew shall remain inside the boat during the race. Any boat that sinks, capsizes, loses a crew member overboard or is swamped shall be disqualified. The boat must be stopped while bailing.


Please define "inside".

Please define "swamped".

Please define "bailing".

Note that the early Canoe racers found that sitting inside could be extremely uncomfortable and required complex side-deck flaps.

You'd probably find that the last sentence in the rule gives an incidentive for people to try to get to the finish half-swamped, which is a dangerous state to sail in. See "When Dinghies Delight" for interesting accounts of the problems and dangers caused by racing before decent bailing was permitted.

A rule that DSQs boats that capsize will normally encourage less seaworthy and safe designs, because buoyancy tanks and bailing facilities like transom flaps cost weight and cash. If you can't use them, people don't put them in.

You therefore end up with people sailing around in tippy half-sunken boats, putting great strains on their rigs.....that's not particularly family-friendly.

Of course to avoid all this, people will simply create boats with no cockpit or minimalist cockpits a la Laser, which is not particularly family-friendly compared to the full size cockpit you can have on such a boat. So rule 9 has made for a much less family-friendly and safe boat than you would have without it.


Note: I did not specifically exclude multis because this can be done effectively by rule #1.
As noted earlier several times, there is over 100 years of experience in drafting rules that could be drawn from. Much of this experience shows that simple rules simply don't work.

Having a committee able to deem things is very hazardous, although much of the time impossible to avoid in certain situations. Reasonable people can come to different opinions, and allowing committees to make judgement calls too much can lead to some very difficult times.
Reply With Quote
  #285  
Old 08-20-2012, 03:31 PM
Petros Petros is offline
Senior Member
 
Join Date: Oct 2007
Rep: 1260 Posts: 1,781
Location: Arlington, WA-USA
I was away from the internet all weekend.

I like the concept however it appears your wood rule would exclude the use of skin-on-frame construction which is very light and inexpensive. The intend is to limit cost, and not creativity, it seems to me this rule would not limit cost but would limit low cost solutions.

I like the idea of a "le Mans" type launch, to start from "trailer ready" condition is a great idea, might change the way some rigs are designed. And making it more practical and useful.

I think a simple box rule of length, beam and height will both limit cost, is easier to measure (and qualify), and there is no ambiguity, so it is a better approach. I suspect any of those proposed changes would result is very long, narrow beam designs. Not really a practical day sailor.

My idea with the cargo plus crew weight crew was also to keep the boats practical, and with some races requiring the cargo box in place, and some without, you also get a measure of the performance at both ends of the gross weight spectrum. And I see no reason to require the builder to also be part of the crew. the object is to find the best performing low cost boat, not the best sailing skilled builder.
Reply With Quote
Reply



Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes


Similar Threads
Thread Thread Starter Forum Replies Last Post
About factor "F" of ABS ORY rules DUCRUY Jacques Class Societies 2 03-31-2010 02:43 PM
Getting Afloats' "racing" Sharpie Single-masted? Dunhill_BKK Wooden Boat Building and Restoration 11 04-27-2006 11:44 PM
CNC made "plug" or mold, cost and finish Raggi_Thor Fiberglass and Composite Boat Building 3 03-09-2006 04:26 PM
Drawing for Rhino of "Boat Racing Chair" and "Machine Gun" Vibtor Software 0 10-02-2004 03:03 PM
Bay City, Michigan "Racing" kaioken Open Discussion: All Things Boats & Boating 0 08-16-2002 01:03 AM


All times are GMT -4. The time now is 04:13 AM.


Powered by: vBulletin Copyright ©2000 - 2013, Jelsoft Enterprises Ltd.
Web Site Design and Content Copyright ©1999 - 2013 Boat Design Net