Basic information on boats

[Guillermo]

In post 116 (http://www.boatdesign.net/forums/showpost.php?p=112326&postcount=116) within the thread on STIX vs Old ratios, Crag Cay posted these very interesting thoughts:
To go further and eliminate the Categories all together is because they, (and the STIX numbers) are trying to convey too much information in a overly simplistic way. This is a disservice to the consumer as it encourages them to be simplistic in return. The information about the boats should be conveyed by a series of indicators without any direct inference as to their suitability for use. This series of values would portray direct information about strength, stability, comfort, range under power, environment concerns, recyclability, etc, and then the consumer would be free to match the demands of his particular use to a particular boat. Lumping all boats above a certain number as being suitable for some generic use, whilst eliminating others of better pedigree, is a nonsense as some of your examples have shown.
(Bolding is mine)
Although worried about the people really understanding what numbers are, I feel an strong affection for Crag's thoughts.
Some questions for everybody: Do you agree with Crag's point of view? If so, What's the minimum information you think should be included in the basic information on a boat? Should that info be mandatory? And down to what degree of detail?

[Willallison]

I'd concur, at least to some extent. The problem isn't just confined to the boating arena, of course. The reality is that, for the most part, the general public don't have the expertise to establish seaworthyness (or otherwise) of a boat. And perhaps more importantly, they're not interested in gaining that knowledge.
STIX, RCD, compliance with ISO and other standards, etc, can at best only give these people a general guide.
But of course, these things are all so significantly effected by weather, load, crew experience etc etc etc.
Dunno - it's a tough one....

[Frosty]

Thats if you choose a boat with your brain. If you choose a boat with your heart --who cares about anything, least of all some numbers or even solid advise from others.

To gain a competative edge the numbers could be embelished or twtsted, then they would become meaningless, unless coverd by law (now I really dont like where this is going).

It all very sensible,--If only human beings were as sensible.

[Willallison]

Thats if you choose a boat with your brain. If you choose a boat with your heart --who cares about anything, least of all some numbers or even solid advise from others.

To gain a competative edge the numbers could be embelished or twtsted, then they would become meaningless, unless coverd by law (now I really dont like where this is going).

It all very sensible,--If only human beings were as sensible.


The day people realise that there's nothing very sensible about spending a million bucks on a toy that might get used 30 days a year, we'll all be in trouble... the boating industry will end there and then!

[Vega]

The reality is that, for the most part, the general public don't have the expertise to establish seaworthyness (or otherwise) of a boat. And perhaps more importantly, they're not interested in gaining that knowledge.
STIX, RCD, compliance with ISO and other standards, etc, can at best only give these people a general guide.
....

Yes, I agree.

I have posted this on other thread, but it makes more sense on this one:



It always amuses me that boat designers have this fascination with these complex formulae and their inherent trade offs.

For all this information to be accessible to the buying public, it should be presented to them in answer to all the natural questions they have when looking for boat. The figures are available anyway, so wouldn't require more disclosure by the manufactures, but at the moment the relevancy of this information is lost when stirred together into the 'pot purri' of STIX or Categorisation.

It's also claimed to have began to help the consumer. So let's build on this second point by developing an information system that is accessible, meaningful, workable and allows the consumer to really make sound choices in the boats they want to buy. The consumer's needs should be the driving force for this process and not just to allow another oppurtunity for boat designers to fiddle with formulae.


Yes I agree with most of what you say. But far meaningless than STIX (regarding stability assessment) were what Guillermo calls “Old Ratios”. Those were very inaccurate tools that are only applicable (and very roughly) to a certain type of boat. They are meaningless if applied to modern bulbed sailboats.

The information that you say is available, is not. The sellers will not have a clue about what you are talking about and the boat manufacturers don’t disclose that information to the public. You have to ask for it, and sometimes they give it to you, others they don’t.

I believe you are overestimating the average knowledge of the typical boat buyer. Fact is that even professional specialized press, completely disregard the information about safety stability in the boats they are testing for their magazines. Even the British press that usually publish the GZ or RM curves of the boats they test, don’t make any comments about them, neither when they are very bad, nor extremely good.

If these guys don’t really know how to interpret those data, how do you expect the average buyer to do it?

STIX has the advantage of simplicity in its interpretation, the bigger the better, and even if far from perfection, it can give you an approximate idea of the boat’s stability. Better than nothing, I would say.

[Guillermo]

Here my first tentative list for the basic information (brochures, web, etc) to be provided for all over 6 m sailing boats, from manufactures/designers:

Basic info:
(metric and imperial units)
LOA,
Lh
Displacement in MOC
Maximum load displacement
Ballast (fixed)
Ballast(movable)
Lwl at MOC
Bmax
Bwl at MOC
Body draught
Total draught (with and without lifting keels and the like)
Engine mark and model
kW or HP (DIN) and rpm at continuous duty condition
Propeller type, diameter and pitch
Fuel tanks capacity
Range at 1.1 (imperial) SLR
I,J,P,E (And mizzens' or other if it's the case)
Heeling arm for IJPE area + lateral hull & deck profile
Sailing areas upwind and downwind
GZ curve for MOC, indicating downflooding angle and GMo
Roll period at MOC
(indicating if measured or estimated for these two last)

Parameters and Ratios:
(imperial and metric units)
Cp
D/L
SA/D
SA/WS
CSF
MCR
Roll Acceleration
SI
Dellenbaugh angle
AVS (Although already constant at the GZ curve, also to be explicited here)
Negative/Positive GZ curve areas ratio

RCD info:
RCD approved Category
STIX and its Factors.
Watertighteness degree of hatches, etc.
Notified Body
Assessment Module used.

Structure & Construction
Rules and regulations used and level attained
Hull & deck type of construction and materials
Basic scantlings
Mast & rigging type, materials and scantlings
Rudder type, material and attachement to stock
Stock material and diameter
Stock bearings
Steering system
Propulsion shaft material and diameter
Propulsion shaft bearings
Engine bed type. Mountings.


Basic equipment list and price,
with marks and models.
(Specifying water and retention tanks)

Optional equipment list
with marks, models and prices (mounted)

Plans/Drawings
Full profile with precise WL at MOC
Interior lay-out
Deck arrangement
Midships section.

Warranty
Type(s) and duration, for construction and equipments


This should be something like a 'Minimum Code of Practice' among designers/manufactures.
Now, your proposals.....

[marshmat]

Guillermo, if all manufacturers disclosed all of that, the number of boatbuilders would be cut in half. The crappy ones couldn't pass off CSM-covered putty as "advanced composites" if all of that info were available to buyers!
Granted, though, it's a good list and I for one would want to know all of that, plus a lot more, before dropping several years' salary on a big hole in the water.
I'm not sure, though, how buyers would react... after all, there are an awful lot of people who can afford a boat, and go out and buy one, and have no real idea how to use it. Let alone understand why it would behave as it would if it ever left its pier.

[Guillermo]

Let alone understand why it would behave as it would if it ever left its pier.
:D :D :D
Absolutely. But we have to try, at least, for the ones who really care.
Cheers

[SuperPiper]

I started to read the list syllable for syllable at the start. After a while, I was scanning and near the end, I was skipping.

Apply this rationale to automobiles. Half the time I can't remember what tire size I need.

Maybe the "condense it all to a single number" idea is not so bad for 99% of the planet.

[Guillermo]

Then, what should a basic spec list include?
Several people at these forums have complained here and there about the lack of info from designers/manufactures and the inadequacy of STIX to tell enough about a boat's seaworthiness (I'm one of those, as evident).
So, let's concentrate only in stability, seaworthiness and performance matters, to not do the list too long, as SuperPiper complains.

Alternative lists....? More opinions....?

[Stephen Ditmore]

I'm afraid you're using abbreviations I'm unfamilliar with, Guillermo. What are Lh and MOC?

It's interesting that angle of vanishing stability, area under the righting arm curve, and area under the inverted righting arm curve are not on your list. Why not? Roll accelleration is there, but not roll period or roll period constant...?

[Mikey]

MOC = minimum operating condition
Lh = the distance measured from the forward end of the foremost outside surface of the hull shell to the aft end of the aftermost outside surface of the hull shell

Mikey

[Guillermo]

It's interesting that angle of vanishing stability, area under the righting arm curve, and area under the inverted righting arm curve are not on your list. Why not? Roll accelleration is there, but not roll period or roll period constant...?
Mikey correctly explained the first part of your question.
AVS is there. Twice. One with the GZ curve and a second and explicit time in 'parameters and ratios'
Roll period is at the end of 'basic info' as 'Roll period at MOC'
I did include the GZ curve, but not the areas (Which anyhow may be explicited at the graphic) because I'm trying to get here a basic specification only as this is info for customers, not NAs. If an NA or other interested people wants to know the areas, well, he/she should work out that from the GZ curve. And I have included the negative/positive area ratio, which is the most relevant info to be known for a customer, not the areas themselves.
Cheers

[RHough]

In post 116 (http://www.boatdesign.net/forums/showpost.php?p=112326&postcount=116)

Some questions for everybody: Do you agree with Crag's point of view? If so, What's the minimum information you think should be included in the basic information on a boat? Should that info be mandatory? And down to what degree of detail?

I agree with Crag for the most part. The information should be available to anyone that cares, so they can make a decision based on their priorities.

Designers and builders of "safe" boats should be free to use the information to promote the "safety" of their boats. Volvo sold cars that don't interest me in the slightest based on "safety". (funny that that they also sponsor the VO70's)

I do not agree that the designers or manufacturers of boats should decide what is best for others. I think fools should be allowed to be fools, and everyone should have choices.

I think that most owners of series production boats are basically clueless. That more of them don't die every year is testimony to the integrity of the designers and builders.

If we want to save lives, we should make boating less attractive to the masses. If we could remind people that their are dragons at the end of the earth they would be less tempted to leave the dock. We can sell them pontoon boats dressed up to look like ocean racers (but with 6 heads and three wet bars) and they can still enjoy their boats as they do now.

I think that many things that have been done to make boating attractive to the masses have done more to make boating unsafe than any hull form. My background is sail boats, but I'm sure the power guys have some of the same thoughts.

Rant:
The great hue and cry for safe cars over better drivers came from the insurance industry. That's what has given us cars that have thousands in extra cost, in order to limit the insurance company liability. If/when insurance companies decide that they are paying out too much money for dead or injured sailors we will see "safety" sailboats.

Do we really want regulations that demand passive safety on our boats?

The requirements might look like this:

"The boat must survive a 4 knot impact with a submerged container. The boat must be unsinkable after the impact. If children are carried, they must be restrained in positive flotation devices and tethered so they cannot go overboard. Any vessel that carries restrained children must be capsize proof or self right from any angle within 90 seconds. In the event of impact of capsize all crew shall be restrained form hitting anything that can hurt them, or all surfaces and structures that could kill or injure a person shall either absorb or deflect energy. No person in any unrestrained position shall be subject to a force exceeding 50g's for 1 second during impact from a speed equal to S/L = 1.1 or a capsize event."

It has been my observation that the level of driving skills has gone down as cars become "safer" and less dependant on driver skill (ABS brakes, traction control, etc). I have no doubt that the skill of sailors has gone down since the introduction of mass produced plastic boats. As more systems and "features" are added, the number of clueless sailors increases.

All systems that allow a novice sailor to think they can control a sail of over 150 sq ft should be banned on boats sold to novices. This includes winches and all forms of roller reefing/furling. All systems that allow jobs best done on the foredeck or at the mast should not be allowed to be lead back to the cockpit. Once a sailor has been certified in a basic type, they can add such systems or purchase a boat with larger sails and more complex systems. This seems to work for private aviation, why not boats?

Cars are sold to people that can't drive and we force them to be more crash-proof. We do little or nothing to certify the driver's ability. Large powerful boats are sold to people that have no seamanship skills. We do little or nothing to certify a sailors ability.

If you want to make boating safer, refuse to design boats that lull their owners into a false sense of security. If people are too frightened to leave the "safety of the cockpit" they are less likely to leave the dock at all, it no longer matters if the boat will capsize or not. :D

End of Rant

[Kaa]

I think fools should be allowed to be fools, and everyone should have choices.
...
Rant:

You understand that the first part of your post -- about people having the freedom to do stupid things -- directly contradicts your rant, which basically states that people who haven't demonstrated competence should not be allowed near anything bigger than a small, basic boat, right?

Kaa

[RHough]

You understand that the first part of your post -- about people having the freedom to do stupid things -- directly contradicts your rant, which basically states that people who haven't demonstrated competence should not be allowed near anything bigger than a small, basic boat, right?

Kaa

Yep, I don't think there is a reasonable or logical answer to the question.

If we (as a society) start removing choices to protect people from being fools, those that are not fools have their choices limited also.

The only way to show that you may not be a fool is to earn some sort of certification. As soon as you say that in the USofA you will get your head handed to you on a platter. Everyone *knows* that 50% of the drivers/sailors/pilots have below average skill (it's the definition of average). Yet hardly anyone will admit to being in the lower 50%.

This whole idea of making safer boats is suspect to me. If there ever was a universal truth, it is that fools can outwit designers any day of the week. The boat can't be built that a fool cannot capsize, set afire, sink, or fall off of.

Lets compare Airplanes, Cars, and Boats for a moment.

Designers know what conditions the aircraft are safe to fly in. Airplanes have a set of stresses above which they will fail. Pilots fly the airplane outside the envelope at their peril. The pilot must be educated and certified to fly airplanes of different types and in different conditions. No one expects airplane designers to create airplanes (except some ultra-lights) that a novice can fly with no training or certification.

Designers know what conditions cars are safe to drive in. Because there is no presumption of driving skill, cars cannot have operational limits in the same way airplanes do. Huge sums of money have been spent to make cars safer *when* they crash. They have to be, the operators have no demonstrated skills to avoid the crash.

A Designer should know what conditions the boats they design are safe in. Do we admit that the sea is almost as unforgiving as the air and place operating limits on our boats? Does it make more sense to lobby for programs to produce better sailors or to lobby for fool-proof boats?

I don't want to see more 27 foot boats with roller furling masts, shoal draft wing keels, standing headroom, and wheel steering. Looking at the new boats that get delivered here, 36 feet seems to be "entry level". The 25-27 foot boats are new to second, third, or forth owners. If you spend time in forums for "Joe Average" the questions that new owners ask are frightening. That the system allows some of these people to own boats is criminal. Someone is going to risk their life sooner or later to save these misguided souls. Not beacuse the boat didn't have a high enough Rolls'Knardly ratio, but because the fool has outwitted a sound design.

Bottom line, if you want to keep people from drowning after boats capsize, teach people not to capsize them. Teach them what conditions will capsize their boat and how to recognize and avoid those conditions. The only reason we are having this debate is because we can change the boats but we can't re-design fools.

[Frosty]

[QUOTE=RHough;116260]

The only way to show that you may not be a fool is to earn some sort of certification.


Or stay alive, those who stay alive pass on intelligent genes and help the world get smarter. Protecting fools will get us nowhere.

Evalution has worked well to get us here. What shall we do, live by rules made for the dumbest person on the planet?

I have already seen silica gell packets with 'do not eat' written on them. Jeeeeess

[Kaa]

Yep, I don't think there is a reasonable or logical answer to the question.

Well, I, personally, is very much in favor of freedom. As one of my favorite bash.org quotes goes, "The problem with America is stupidity. I'm not saying there should be a capital punishment for stupidity, but why don't we just take the safety labels off of everything and let the problem solve itself?" :D

In my view, this is one of those situations where the cure is worse than the problem. I'd much rather suffer incompetents bumble around in large vehicles than have another layer of bureacracy that decides what it allows me to do and what it does not allow. The sea is open and free. I would like it to stay open and free.

The only way to show that you may not be a fool is to earn some sort of certification.

In the same way that a driver's licence shows you are a competent driver? :-)

And, by the way, people who buy sailboats tend to look like shining examples of sanity and prudency compared to those who buy powerboats...

This whole idea of making safer boats is suspect to me. If there ever was a universal truth, it is that fools can outwit designers any day of the week. The boat can't be built that a fool cannot capsize, set afire, sink, or fall off of.

Don't think about absolutes, think about percentages. An unsinkable boat full of floation is safer than a lead mine because the fools' chances on it are better. Doesn't mean they won't find a way to sink it or die from exposure, or something else -- just means that a lesser percentage of them will die. And that means it's a safer boat. Not absolutely safe -- just safer.

Does it make more sense to lobby for programs to produce better sailors or to lobby for fool-proof boats?

It makes more sense to let things be and not introduce government regulation into this whole thing. The only thing I would force on designers/manufacturers is full disclosure of information. If there's nothing in your hull but chopped mat, everyone should know this. If people who know this still want to buy the boat, let them. Eventually natural selection will sort this out :-)

That the system allows some of these people to own boats is criminal.

To remind you, that system is called "freedom".

Kaa

[RHough]

In the same way that a driver's licence shows you are a competent driver? :-)

It makes more sense to let things be and not introduce government regulation into this whole thing. The only thing I would force on designers/manufacturers is full disclosure of information. If there's nothing in your hull but chopped mat, everyone should know this. If people who know this still want to buy the boat, let them. Eventually natural selection will sort this out :-)


To remind you, that system is called "freedom".

Kaa

Nice try. Every time you mention a certification program for boats that old horse gets trotted out. :D

I'm sure you know the difference between licensing and certification. Nice troll though.

The regulations that govern aviation don't remove the freedom to fly airplanes. "Freedom" is earned by showing responsibility. If you cannot act responsibly, your freedoms should quite rightly be reduced.

[Frosty]

[QUOTE=RHough;116271. "Freedom" is earned by showing responsibility. If you cannot act responsibly, your freedoms should quite rightly be reduced.[/QUOTE]

I remember my school teacher saying that,--- when I was 8 !!

[Kaa]

I'm sure you know the difference between licensing and certification. Nice troll though.

There is certification for sailing. ASA, for example, would be happy to give you a bunch of certificates in exchange for money and some of your time. The problem is, nobody cares much about these certifications, not even the bareboat charters.

"Freedom" is earned by showing responsibility. If you cannot act responsibly, your freedoms should quite rightly be reduced.

We seem to have a basic philosophical disagreement. I don't think that you "earn" freedom, certainly not by showing to the authority that you've been a good boy. You have freedom to start with, you are born with it.

Sure some of that freedom can be taken away as a consequence of your actions, but note -- consequence, not precondition. And you don't need any new system for it, a judge can perfectly well order someone to stay away from boats if he thinks that someone is dangerous on a boat.

But anyway, this thread is not about philosophy, but about information disclosure for boats. I am a big fan of full disclosure and that's the situation where I am willing to make an exception to my general dislike of government regulation. But after that, if you still want to sail out on that contraption that you know is likely to disintegrate when somebody sneezes into its direction -- it's your choice.

Kaa

[Frosty]

You have freedom to start with, you are born with it.Kaa

Did any one ask you if you wanted to be born? did you choose your colour, your race ,your parents, your nationality, your religion, your name, or even your sex?

Not wanting to argue for arguments sake but birth can be a pretty bum deal with absalutely no freedom what so ever for a lot of people on this planet.

[RHough]

There is certification for sailing. ASA, for example, would be happy to give you a bunch of certificates in exchange for money and some of your time. The problem is, nobody cares much about these certifications, not even the bareboat charters.

I'm well aware of that program. Some of a the CYA instructors helped develop it. It is a start. I can say that the sailors that have passed the CYA intermediate course are more knowledgeable (not as experienced perhaps) than many sailors. I agree that people not caring about the certification process is a problem.

In the US, the trend seems to be to expect the people that use a service to pay for it. How about holding the seller or the charter company liable for SAR expense if they provide a boat to an uncertified user?

If you don't have a problem with forcing full disclosure, you agree that government/society has a right to require some action. Does not that lessen the freedom of the builders and sellers?

The model for private aviation seems to work pretty well. I doubt that you can charter an airplane without showing proof of certification and possibility taking an instruct for a test flight before they let you loose with the plane. What's the big deal?

I don't think that we disagree very much. With freedom comes responsibility.

If we don't choose to act responsibly our activity might get banned ... PWC's are a prime example.

[Kaa]

If you don't have a problem with forcing full disclosure, you agree that government/society has a right to require some action. Does not that lessen the freedom of the builders and sellers?

Generally speaking, I'm interested in the maximization of choices and limiting the power of the government. Forcing full disclosure does nothing to the power of the government (as opposed to e.g. a licensing program) and only limits the choice of lying or concealing information. I'm OK with that.

The model for private aviation seems to work pretty well. I doubt that you can charter an airplane without showing proof of certification and possibility taking an instruct for a test flight before they let you loose with the plane. What's the big deal?

The model for private aviation is entirely inappropriate for boating. The risks faced in these two areas are very different. Put crudely, if you seriously screw up in an airplane you're likely to die. If you seriously screw up in a boat, you are very unlikely to die.

And as to chartering, I have no objections to bareboat charters demanding whatever they want of their prospective clients. They are private entities and can do what they please. What I strongly dislike is any kind of scheme that effectively says "Unless you have this piece of paper you're not going out onto the water, period."

Kaa

[Guillermo]

Hey guys, love your philosophical approaches to the matter, but I would appreciate some specifical proposals on the technical 'basic info list' or on technical regulations, if possible.

like the interesting Randys' proposal:
"The boat must survive a 4 knot impact with a submerged container. The boat must be unsinkable after the impact. If children are carried, they must be restrained in positive flotation devices and tethered so they cannot go overboard. Any vessel that carries restrained children must be capsize proof or self right from any angle within 90 seconds. In the event of impact of capsize all crew shall be restrained form hitting anything that can hurt them, or all surfaces and structures that could kill or injure a person shall either absorb or deflect energy. No person in any unrestrained position shall be subject to a force exceeding 50g's for 1 second during impact from a speed equal to S/L = 1.1 or a capsize event."

More thoughts in this line, please.

By the way: personal freedom ends where other people one's begins. The problem is not the stupid or irresponsible ones killing themselves, which is probably desirable in the natural order of things, but killing or risking lifes of other people in the process (family, friends, third parties, rescuers, etc).

Cheers.

(P.S.: And stupid and irresponsible people's mistakes also involve all of us: We end paying higher insurance fees because of them!)

[marshmat]

On the whole licensing thing. Canada has this for pleasure craft now as well as commercial, it's almost fully implemented. And simply going out on the lake you can tell that those who have it so far- younger drivers and those in smaller craft and PWCs- have vastly improved seamanship and much more respectful behaviour than five years ago. Those who don't- mostly older folks with bigger boats, who still have some time before they must have the card- often show a remarkable disrepect for other boaters, and seem to do stupid and highly dangerous things a lot more than those who have it. The card costs very little and is good for life, and the test- if you know the rules of the road and a bit about safety and common sense- is easy to do well on. But the process of studying for it makes just about everyone a smarter, more respectful seaman. Not to imply that this is what you Yanks need, but it is working incredibly well up here as far as I can tell.

As to the boats themselves. I don't think it's feasible to regulate every aspect of design. But I do think full disclosure is in order. The customer should be able to ask for, and receive, any information they want about the boat that's not proprietary. GZ curve, key ratios, scantlings used and safety factors, hull structure.... Educating the consumer is a big thing here, it's very easy to sell crap if your customer doesn't know the difference between crap and solid design. Perhaps the industry associations should be publishing (free) information for buyers teaching them how to evaluate a boat for their needs, what questions to ask, etc. in much the same way consumer organizations do for carmakers. Possible, you think?

[RHough]

On the whole licensing thing. Canada has this for pleasure craft now as well as commercial, it's almost fully implemented. And simply going out on the lake you can tell that those who have it so far- younger drivers and those in smaller craft and PWCs- have vastly improved seamanship and much more respectful behaviour than five years ago. Those who don't- mostly older folks with bigger boats, who still have some time before they must have the card- often show a remarkable disrepect for other boaters, and seem to do stupid and highly dangerous things a lot more than those who have it. The card costs very little and is good for life, and the test- if you know the rules of the road and a bit about safety and common sense- is easy to do well on. But the process of studying for it makes just about everyone a smarter, more respectful seaman. Not to imply that this is what you Yanks need, but it is working incredibly well up here as far as I can tell.

As to the boats themselves. I don't think it's feasible to regulate every aspect of design. But I do think full disclosure is in order. The customer should be able to ask for, and receive, any information they want about the boat that's not proprietary. GZ curve, key ratios, scantlings used and safety factors, hull structure.... Educating the consumer is a big thing here, it's very easy to sell crap if your customer doesn't know the difference between crap and solid design. Perhaps the industry associations should be publishing (free) information for buyers teaching them how to evaluate a boat for their needs, what questions to ask, etc. in much the same way consumer organizations do for carmakers. Possible, you think?

Don't tell Kaa about how well it works. :D

I agree about making the information available to those that are interested. The top three or four numbers should also have the range and median values for similar boats printed. Just like they do for energy usage on appliances and cars.

"This boat has a STIX of 30, the range of STIX values for other Category B boats of this size (27-30 ft) is from 21 to 45, the average is 27."

The buyer then knows that there is a very stable boat out there that has a STIX of 45, but 30 is higher than most boats that are similar.

[marshmat]

Agreed, a number on its own is useless without a range and average for comparable products.... do it like EnerGuide does, ya, that works well. Builder's marketing guy takes a look at the main competitors and buyer gets some statistically legitimate points of comparison between them. Again, though, you'll have a hard time getting the builders who sell CSM-filled junk to go along...

[Guillermo]

Randy's idea is nice, but people should be educated first about the meaning of STIX. And the actual tendency from manufacturers is to hide it, not educate. It seems they do not like at all the STIX idea. Even designers seem to be avoiding the thing. It's interesting to realize that very few sailboat designers around in these forums, even very collaborative ones in other matters, have written a single line on it at these related threads....Would I myself be so persistent with all this if I were a sailboats designer pretending to sell my designs to all kind of clients...? I'm not sure.
Cheers.

[Mikey]

Here my first tentative list for the basic information (brochures, web, etc) to be provided for all over 6 m sailing boats, from manufactures/designers:
......
Now, your proposals.....

Guillermo, I lack a way to measure hull asymmetry in a quantitative way.

... discussed by designer Cyrus Hamlin in his book "Preliminary Design of Boats and Ships", pages 195-197. His method is to calculate heeled LCF (center of the waterplane) at 30 deg (25 deg for flat bottomed/shoal draft hulls) without allowing the hull to retrim from static upright trim. He then takes the distance between the upright and heeled LCF's as a percentage of waterline length. Hamlin recommends that the LCF should shift aft as the boat heels, but the shift should be less than 1% of DWL

Marchaj discusses the same but doesn't quantify it, Hamlin does.

I would expect a Pogo 40 to show up way above 1%, if we ever get the possibility to check it, that is.

Mikey

[RHough]

Randy's idea is nice, but people should be educated first about the meaning of STIX. And the actual tendency from manufacturers is to hide it, not educate. It seems they do not like at all the STIX idea. Even designers seem to be avoiding the thing. It's interesting to realize that very few sailboat designers around in these forums, even very collaborative ones in other matters, have written a single line on it at these related threads....Would I myself be so persistent with all this if I were a sailboats designer pretending to sell my designs to all kind of clients...? I'm not sure.
Cheers.

I like to think of myself as more knowledgeable than most sailors (don't we all?).

I had never heard of STIX until I saw it on this forum. Not wanting to feel like an idiot, I searched for "STIX" ... and got "Did you mean STYX?" ... STYX? The river to hell? I don't want much of that on my boat! ... Oh STIX? Like Pick-up STIX? ...11 pages in I still know nothing about STIX in relation to boats ...

If I search "boat stability index" I start getting some information including this page "Estimating Stability" (http://www.johnsboatstuff.com/Articles/estimati.htm) ... now I'm found some terms I've Heard before ... D/L ratio; SA/D; ...;Capsize Risk (from the 1979 Fastnet study); Comfort Factor ...

Four or five ratios and numbers that I'm semi-familiar with ...

If the range and median values for other 30 foot boats were compared to mine I would know at a glance what to expect of my boat.

STIX? No thanks, I'm not ready to cross to the underworld just yet ... :)

Perhaps others have the same initial reaction to the name STIX as I?

Perhaps STIX doesn't favour the boats that keep the factories busy building boats?

Before the industry and designers will embrace a new evaluation formula it can't favour 40-50 year old designs over what sells and what has been proved to be "seaworthy enough".

[Kaa]

Well, speaking of full information disclosure for boats I think something like this should be OK.

I envision three levels of information available to boat buyers.

Level one is very simple. It is, basically, the statement of the fact that the boat is certified to fit a certain standard and should be depicted as a logo. The certification (and the creation of open, published standards) should be carried out by non-government non-industry organization which should be set up for this purpose -- e.g. something like the Underwriters' Labs.

As to the standards themselves, there should be several of them (less than 10, though). One possible idea is to take the existing EU system (A, B, C, D) of suitability to certain type of sailing and within each specify two safety classes -- let's call them Gold (extra-safe) and Silver(normally-safe). Thus a standard might be, for example, B-Silver. A boat which carries a B-Silver logo is certified to be safe (but not extra-safe) for offshore sailing.

Note that I think this system should be voluntary -- that is, you should be able to sell boats which didn't pass the certification. However then you'd have no logo to display and would have to tell the buyers that the boat didn't pass any certification.

The whole point of level one information is to be simple. If your Aunt Mabel goes batty and wants to take up sailing, you should be able to tell her to just buy any D-Gold boat and try it out :-)

Level two is a couple of sheets of technical data about the boat. The usual basics, plus the standard ratios, etc. These sheets should come with a free booklet explaining what the words and the numbers mean and what kind of trade-offs are involved.

Level three is request for technical data from the builder which the builders would be obligated to answer unless it involves a trade secret. And no, making hulls out of pure CSM does not count as a trade secret, and neither does using cardboard as core X-). If this system comes to pass, I expect many websites with VERY detailed information about the popular boat models.

Such a system I would consider reasonable.

Kaa

[Guillermo]

Interesting contribution Kaa. Could you please develope and specify what you call level two?
Cheers.