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  #1  
Old 01-30-2005
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Bluewater defined?

Are Freedom Yachts considered bluewater? It seems that a "bluewater" boat is always judged on its'' displacement and full keel, yet I have seen some Freedoms with shoal keels. Am a I interpreting the word bluewater too loosely? I have a Beneteau that is probably considered coastal yet it displaces more than some of the Freedom Yachts. Help me to understand who defines the notation of a boat as being bluewater?

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dch
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Old 01-30-2005
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Bluewater defined?

The definition of a Bluewater boat is a controversial one. It really depends on the risks you are prepared to take, the level of comfort (energy), the crew (number) of your boat, the level of seamanship etc.

For me, if it is a boat under 45ft, an AVS of at least 130 is a basic requirement.

See this site, I think they provide good advice:

http://www.windpilot.de/en/Ra/rayacen.html

Paulo
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Bluewater defined?

In the final analysis, the capabilities of a boat (bluewater, coastal, inland, etc) are determined by the master (& crew) - and second guessed by everyone else.

STIX Categories:

“A” (Unlimited Ocean) STIX Value >32 - adequate to withstand up to a force 10 gale, with average waves of 7 m height and eventual wave heights of 14 m.

“B” (Offshore) STIX Value >23 - adequate to withstand up to force 8 winds, with average waves of 4 m.

“C” (Coastal) STIX Value >14 - adequate to withstand up to force 6 winds , with average waves of 2 m.

“D” (Local) STIX Value >5 - adequate to withstand up to force 4 winds, with waves of 0.5 m maximum.

References:
http://www.rorc.org/programme/stix.php
http://www.yachting-world.com/yw/stability/stability97.pdf
http://rorcrating.com/stix/stixpaper.pdf

FWIW,
Gord
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Old 01-31-2005
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Bluewater defined?

Bluewater: (noun) the overboard discharge after adding head deodorizer.
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Bluewater defined?

I said that it was controversial...

Some confusion (it is confusing) between RORC STIX and STIX as it is defined by ISO 12217-2 (and mandatory by Directive 94/25/EC of the European Parliament). The second is the one that is important, being actually taken with dynamic tests with the boat on the water.


The Classes stated by GordMay are the ones that are defined by the European Directive and every boat sold in Europe has to pass tests to conform to one of them.

Those classes are better than nothing but unfortunately the A class has (in the general opinion) too low standards for the definition of an oceangoing boat.

Almost all light construction European 36ft are A boats, I mean the Bavaria 36, The Beneteau 36, The Jeanneau 36, etc.

Fact is that the specialized press doesn’t call them Oceangoing boats or bluewater boats and I agree. They are basically good coastal boats. That doesn''t mean that they can not make passages, it only means that they weren''t designed for that.

On the other hand, Stix value and AVS ( or LPS) found by dynamic tests are very important to determine the seaworthiness of a boat.

"For ocean-going and offshore yachts one of the most easily seen and meaningful aspects of a GZ curve is the AVS.
But a GZ curve and its AVS are by no means the whole transverse static stability story. A boats mass (displacement) is also very important.

A lever, when multiplied by the force pushing it, becomes a moment. With a boat the lever is the GZ and the force is the boat’s mass. So by multiplying GZ by the boat’s mass gives a righting moment (RM) curve. As the area under this curve represents the energy needed to heel the boat, then for the same GZ curve, a boat of double the mass will need twice the energy to capsize (and twice the energy to re-right after capsize).

ISO 12217

It is for this reason that the recently launched International Standard dealing with the stability of monohull ballasted sailing yachts (ISO 12217-2) uses both AVS and mass as its two main static stability limits.
RCD* Category A boat limits are a minimum mass of 3.0 tonnes and an AVS greater than (130 – (2 x mass)) but always equal to or greater than 100"....

"STIX

STIX, which scores a boats stability on a scale of 1 to 100, uses a boats length as it’s prime factor adjusting this by seven other factors including assessment of a boat’s

• ability to withstand a capsize by considering the area under it’s GZ curve,
• recovery from inversion by looking at it’s AVS and mass,
• recovery from knockdown by overcoming water in the sails,
• displacement-length factor giving credit for a heavy displacement for a given length,
• beam-displacement factor recognizing problems associated with topside flare and excessive beam,
• wind moment representing the risk of flooding due to a gust and
• the risk of downflooding in a broach or knockdown.
STIX is arguably the most sophisticated stability screening tool yet available. The required RCD* STIX limits which are applied in addition to the above limits on mass and AVS are:-

Category A equal to or greater than 32"


http://europa.eu.int/smartapi/cgi/sga_doc?smartapi!celexapi!prod!CELEXnumdoc&lg=en&n umdoc=31994L0025&model=guichett

http://www.rya.org.uk/images/uploaded/3352ce73-ea82-4eb8-a0a6-865dfa94e88a/Stability_Intro.pdf


32 is not a big figure for Stix and it is very close to the figures that those light displacement 36ft(Benetau, Bavaria, Jeanneau) have, with normally an AVS that goes from 115 to 125 .

For instance a Malo 41 has 55,4 with an AVS of 132; a Southerly 135 has a Stix of 59,7 and an AVS of 150; the Regina de Vindo 38 has a Stix of 46 and an AVS of 134.

I would not call the first ones Bluewaterboats, but I think everybody would say that the last ones are (and they are referred as that by the specialized press) and they don''t have full keels.




Paulo
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Old 01-31-2005
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Bluewater defined?

It is hard to answer your question specifically. To a great extent this is a question of definition. Much of this is rather long discussion is exerpted from early discussions on the topic of what makes an offshore capable vessel;

As I have noted in prior discussions, the term ''bluewater capable'' seems to get bandied about as if it had some kind of fixed meaning that can be measured on some absolute scale. To some, this term seems to mean that the boat is safe to take on an offshore passage, while to others it seems to imply an ability to distance cruise to remote locations. This range of interpretations would imply a broad spectrum containing very different kinds of boats.

Most well constructed coastal cruisers are perfectly seaworthy for a carefully timed offshore passage. What they often lack is the kind of layout and design details that make offshore passages comfortable.

Where coastal cruisers fail as long distance offshore cruising boats is in the ability to withstand the large amount of wear and tear that long distance cruisers incur in a very short period of time. As I have noted before in these discussions, a heavily used coastal cruiser might sail something on the order of 1000 miles in a year with most boats sailing considerably less than that. A boat being used for distance voyaging can often sail well in excess of 10,000 miles in a year, with much of that passagemaking in the harsh environment of the tropics.

There is often a tendancy to focus on such items as the AVS (angle of vanishing stability, which by the way I personally prefer the older, more widely accepted, and more linguistically accurate term LPS- limit of positive stability)or STIX (CE Stability Index) as key elements of the overall safety of a boat offshore.

These numbers represent a very small snapshot of the real safety of a boat and as such can be grossly misleading. An extremely high AVS or STIX can be easily achieved simply by designing an excessively narrow boat with lots of freeboard, but with that excessively narrow beam and high tophamper, comes a greatly increased likelihood of a capsize or roll over and a deterioration in motion comfort and carrying capacity.

In following the research process that resulted in STIX, it should be understood that the purpose in developing the CE Directive for Recreational Watercraft, of which STIX is a component, was never to extablish an absolute standard for vessels going offshore. Instead it was intended to develop a minimum and easily quantifiable standard that all of the CE countries could agree upon. In doing so, key calculations and measurements were omitted from the standards because member nations considered them to be onerous. Instead simplified surrogate formulas were substituted for actual more sophisticated calculations resulting in very loose and sometimes missleading approximations. This is especially unfortunate since there was adequate detailed research to have permitted very accurate stability assessments to made.

AVS suffers from another problem as well. As has been pointed out many times on this forum, there is no uniform standard for calculating AVS. It is not unusual to see very high AVS figures quoted in ads, but they mean little in an absolute sense because of the wide range of methods used to calculate a boat''s AVS. Some published angles are for boats in their most advantageous loadings (full water tanks and empty lockers) while other are at their worst (IMS calcs with empty tanks, and which do not include the volume of the cabin). None of these numbers take into account the weight distribution and buoyancy of the vessel in the inverted condition which can greatly alter the relative stability of individual vessels as the approach their limits of positive stability.

When I think of a coastal cruiser vs. a dedicated offshore boat, there are a number attributes that I look for:

-Accommodations:
On a coastal cruiser there should be good wide berths, with enough seaberths for at least half of the crew for that night run back to make it to work the next day. An offshore cruiser is often handled by a smaller crew and so fewer berths and fewer seaberths are necessary. The berths on an offshore boat should be narrower and have leeboards or lee cloths to keep the crew in place on either tack. On both types I would look for a well-equipped galley but the galley needs to be larger on a coastal cruiser so that there is adequate space to prepare meals for a larger crew or a raft-up. For coastal cruising large un-interupted counter tops are great for preparing elegant spreads and are easier to keep clean, but for offshore use can result in flying food. Deep sturdy fiddles that divide the counter into smaller segments work better for offshore cruising. Refrigeration is less important on a coastal cruiser although the case can be made for no refrigeration or icebox if you are going distance voyaging offshore. Large open cabin soles make coastal cruisers seem air and roomy, but offshore provide little foothold for crew moving around a heeled and bucking cabin.

-Cockpit:
A comfortable cockpit for lounging is very important on a coastal cruiser. It should be larger than an offshore boat to accommodate a larger number of people, which is OK since pooping is less likely to occur doing coastal work.

-Deck hardware:
While gear for offshore boats need to be simple and very robust, coastal cruisers need to be able to quickly adapt to changing conditions. Greater purchase, lower friction hardware, easy to reach cockpit-lead control lines, all make for quicker and easier adjustments to the changes in wind speed and angle that occur with greater frequency. There is a big difference in the gear needed when ‘we’ll tack tomorrow or the next day vs. auto-tacking or short tacking up a creek.

-Displacement:
Offshore boats need to be heavier. They carry more stuff, period. The traditional rule of thumb was that an offshore boat needs to weigh somewhere between 2 1/2 (5400 lbs) and 5 long tons (11,000) per person. A coastal cruiser can get by with less weight per crew person but generally is cruised by a larger crew. The problem that I have with most selection processes is that most offshore sailors and many coastal cruisers seem to start out looking for a certain length boat and then screen out the boats that are lighter than the displacement that they think that they need. This results in offshore boats and some coastal cruisers that are generally comparatively heavy for their length. There is a big price paid in motion comfort, difficulty of handling, performance and seaworthiness when too much weight is crammed into a short sailing length.

I suggest that a better way to go is to start with the displacement that makes sense for your needs and then look for a longer boat with that displacement. That will generally result in a boat that is more seaworthy, easier on the crew to sail, have a more comfortable motion, have a greater carrying capacity, have more room on board, and be faster as well. Since purchase, and maintenance costs are generally proportional to the displacement of the boat the longer boat of the same displacement will often have similar maintenance costs. Since sail area is displacement and drag dependent, the longer boat of an equal displacement will often have an easier to handle sail plan as well.

It is important to understand that in and of itself, weight does nothing good for a boat. Weight does not add strength. It does not make for a more comfortable motion. It does not add stability. It does not make for greater carrying capacity. Weight only breeds more weight. Adding weight begins a design cycle that can make a boat harder to handle and more expensive to build with few if any improvements to the boat itself. To explain, as a boat becomes heavier drag increases. As drag increases the sail plan needs to get larger. With increased sail area, there is a greater need for stability. To gain that greater stability, ballast weight and drag increases which starts the another cycle of weight increases. With greater sail area and stability, hull structure needs to get heavier, and, rigging and spar sizes need to increase, and with that greater weight comes the need for still more sail area and stability. With the greater weight aloft comes greater roll angles, a reduction in AVS and an increased likelihood of capsize or knockdown. When the cycles stops, the larger sail plans of a heavier displacement boat makes them harder to handle and that weight increase is in places that do not add to weight carrying capacity. Weight does nothing good for a boat!
-Keel and Rudder types:
I would say unequivocally that for coastal cruising a fin keel is the right way to go here. The greater speed, lesser leeway, higher stability and ability to stand to an efficient sail plan, greater maneuverability and superior windward performance of a fin keel with spade rudder (either skeg or post hung) are invaluable for coastal work. Besides fin keels/bulb keels are much easier to un-stick in a grounding. In shallower venues a daggerboard with a bulb or a keel/centerboard is also a good way to go.

There is a less obvious choice when it comes to the keel and rudder type for offshore cruising. Many people prefer long or full keels for offshore work but to a great extent this is an anachronistic thinking that emerges from recollections of early fin-keelers. Properly engineered and designed, a fin keel can be a better choice for offshore work. Here though is the rub. Few fin keelers in the size and price range that most people are considering are engineered and designed for dedicated offshore cruising.

Full or long keels offer quite a few advantages when cruising off of the beaten path, such as the ability to safely dry out on a remote beach or haul out on an old style marine railway.

-Ground tackle:
Good ground tackle and rode-handling gear is important for both types but all-chain rodes and massive hurricane proof anchors are not generally required for coastal cruising.

-Sailplan:
At least along the US East Coast, (where I sail and so am most familiar with) light air performance and the ability to change gears is important for a coastal cruiser. It means more sailing time vs. motoring time and the ability to adjust to the ''if you don''t like the weather, wait a minute'' which is typical of East Coast or Great Lakes sailing. If you are going to gunkhole under sail, maneuverability is important. Windward and off wind performance is also important.

With all of that in mind I would suggest that a fractional sloop rig with a generous standing sail plan, non- or minimally overlapping jibs, and an easy to use backstay adjuster is ideal for a coastal cruiser. This combination is easy to tack and trim and change gears on. I would want two-line slab reefing for quick, on the fly, reefing. I would want an easy to deploy spinnaker as well.

More and more designers of offshore crusiers are turning to fractional rigs for distance cruisers as well. This switch seems to be especially popular in Europe rather in the States where the cutter rig still seems to the default answer for long distance voyaging.

-Speed:
I think that speed is especially important to coastal cruising. To me speed relates to range and range relates to more diverse opportunities. To explain, with speed comes a greater range that is comfortable to sail in a given day. In the sailing venues that I have typically sailed in, being able to sail farther in a day means a lot more places that can be reached under sail without flogging the crew or running the engine. When coastal cruising speed also relates to being able to duck in somewhere when things get dicey.

It is harder to make the case for the need for speed in an offshore or distance cruiser. Speed can be an asset to an offshore cruiser. More speed means fewer days at sea and less motoring time. That results in a greater range without restocking and so a reduced need for tankage and the need carry less supplies. Argueably greater speed allows an offshore vessel to strategically deal with weather patterns, which when coupled with better weather forecasting information can be a real safety advantage. That said, it is rare that even a very fast boat can ''out run a hurricane''.

-Ventilation:
Good ventilation is very critical to both types. Operable ports, hatches, dorades are very important. While offshore, small openings are structurally a good idea, for coastal work this is less of an issue.

-Visibility and a comfortable helm station:
Coastal boats are more likely to be hand steered in the more frequently changing conditions, and higher traffic found in coastal cruising and are more likely to have greater traffic to deal with as well. A comfortable helm position and good visibility is critical. Offshore, protection of the crew becomes more important.

Storage and Tankage:
There is a perception that coastal cruisers do not need as much storage. I disagree with that. Coastal cruisers need different kinds of storage than an offshore boat but not necessarily less storage. Good storage is needed to accommodate the larger crowds that are more likely to cruise on a short trip. Good water and holding tankage is important because people use water more liberally inshore assuming a nearby fill up, and with a larger crew this takes a toll quickly. Holding tanks are not needed offshore but they are being inspected with greater frequency in crowded inshore harbors and there are few things worse than cruising with a full holding tank and no way to empty it. Offshore boats generally need larger and segregated fuel tanks with fuel scrubbing capabilities. Offshore vessels can tolerate more less convenient long term storage areas.

Respectfully
Jeff
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Bluewater defined?

DCH, I think you can see from the replies posted so far (Jeff''s being the exception...) that the terms ''offshore capable'' and ''bluewater boat'' are so variable in connotation that it''s pretty natural for folks to run to organizational specifications (RORC, RCD et al.) in lieu of anything more comprehensive and meaningful.

As one example, you''d no doubt agree that - by definition - any boat that is to be used for bluewater cruising (extended, offshore passagemaking) must also serve suitably as a home...yet you''ll find no govt''l specs on this important dimension, and so most folks definitions tend to omit it altogether. (OTOH you''ll notice that some of Jeff''s comments at least touch tangentially on this issue). A related example is the issue of ergonomics: it would be a pretty natural assumption that any boat intended to be sailed long distances by humans would fit the human body and the demands placed on it...yet you''ll often find huge disparities between the details of how a boat is built and what seems to ''fit'' and be comfortable at sea.

To get back to your basic question, your first challenge isn''t to figure out how ''bluewater-capable'' a Freedom is, but rather to determine what you think you mean by ''bluewater''. This ''first things first'' definition is often finessed (and therefore ignored) by folks who post questions like yours when they state something like ''I plan to head for the Caribbean and, who knows, maybe into the Pacific...'' Such sloppy, open-ended thinking results in one of two approaches to picking a boat suitable for its planned use: either the boat must be totally capable of all types of ocean sailing, and will consequently be more expensive and perhaps more extreme in design than is necessary OR the criterion is so vague and all-inconclusive that it serves no useful purpose in screening out some boats and certifying others as suitable.

I''d encourage you to do some basic reading about cruising boat design issues, as you''ll get a much better answer than any BB can offer. Examples include The Nature of Boats by Dave Gerr, the Cruising Handbook by Nigel Calder, and many many more.

Jack
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Old 02-01-2005
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Bluewater defined?

Wow! Thanks for all of this information. While some was a little cerebral, I understood the basics especially from Jeff. Thank you all very much.

dch
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Old 02-02-2005
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Bluewater defined?




Even if I agree with a lot of things that Jeff has said (about oceangoing boats) I consider that his opinions on AVS, Stix numbers and in Stability are in the least misleading. In many cases they are simply untrue and they don’t contribute at all for the general understanding and the importance of the issue in the global evaluation of a boat, with special incidence on safety.

Let’s see what I mean:

Jeff said:

“In following the research process that resulted in STIX, it should be understood that the purpose in developing the CE Directive for Recreational Watercraft, of which STIX is a component, was never to extablish an absolute standard for vessels going offshore. “

I say:

That, in my opinion, is not true. The purpose of that directive (that has the value of a law and is mandatory to all state members) was precisely to establish absolute standards that all boats have to conform to be classified in four different categories . Those categories are defined by parameters regarding the minimum safety characteristics a boat has to have, regarding uses in different sea conditions. From the Directive:

“Definitions:

A. OCEAN: Designed for extended voyages where conditions may exceed wind force 8 (Beaufort scale) and significant wave heights of 4 m and above, and vessels largely self-sufficient.
B. OFFSHORE: Designed for offshore voyages where conditions up to, and including, wind force 8 and significant wave heights up to, and including, 4 m may be experienced.
C. INSHORE: Designed for voyages in coastal waters, large bays, estuaries, lakes and rivers where conditions up to, and including, wind force 6 and significant wave heights up to, and including, 2 m may be experienced.
D. SHELTERED WATERS: Designed for voyages on small lakes, rivers, and canals where conditions up to, and including, wind force 4 and significant wave heights up to, and including, 0,5 m may be experienced.”

” Boats in each Category must be designed and constructed to withstand these parameters in respect of stability, buoyancy, and other relevant essential requirements listed in Annex I, and have good handling characteristics.”


So category Class A means unrestricted ocean going boat.


Jeff said

“There is often a tendancy to focus on such items as the AVS … or STIX (CE Stability Index) as key elements of the overall safety of a boat offshore. These numbers represent a very small snapshot of the real safety of a boat and as such can be grossly misleading………….”


I say:

For practical effects, what provide the real separation of boats in class are the stability requirements. Many of the boats in other classes can satisfy all requirements of ClassA except Stability requirements as they are defined by ISO 12217-2:

RCD stands for Recreational Craft Directive, an EU Directive setting down minimum safety standards for the construction of recreation craft .

“RCD Category A boat limits are a minimum mass of 3.0 tonnes and an AVS greater than (130 – (2 x mass)) but always equal to or greater than 100º.

RCD Category B boat limits are a minimum mass of 1.5 tonnes and an AVS greater than (130 – (5 x mass)) but always equal to or greater than 95º.

.The required RCD STIX limits which are applied in addition to the above limits on mass and AVS are:-

Category A equal to or greater than 32

Category B equal to or greater than 23 “


“STIX, which scores a boats stability on a scale of 1 to 100, uses a boats length as it’s prime factor adjusting this by seven other factors including assessment of a boat’s

ability to withstand a capsize by considering the area under it’s GZ curve.

recovery from inversion by looking at it’s AVS and mass.

recovery from knockdown by overcoming water in the sails.

displacement-length factor giving credit for a heavy displacement for a given length.

beam-displacement factor recognizing problems associated with topside flare and excessive. Beam.

wind moment representing the risk of flooding due to a gust and
the risk of downflooding in a broach or knockdown.”


STIX number was made from and by :

“ It was from work on these two screening formulae (The RORC Triple S Numeral developed in the 1980s and the RYAs own STOPS number used for smaller MCA Code vessels since the 1990s) that the ISO working group drafting the new stability standard developed its own stability index screen known as STIX. The RYA played a major part in this work.”

RORC stands for Royal Ocean Racing Club, RYA for Royal Yacht Association and MCA for Maritime & coastguard Agency.


I say:

These technicians, (the ones responsible for the technical safety stability requirements that the boats need to fulfill to be to classified in each one of the four EU categories) the naval architects that work for RORC and RYA, know a lot more about stability and safety than me or Jeff or any amateur.

They are professionals that have been working in this field since that race of bad memory, and have been responsible for the previous systems used to make offshore racing and small commercial vessels (including commercial sail boats) safer.

If they consider AVS , STIX numbers and Mass as the key elements of the overall safety of a boat , it is in my opinion very misleading to say , as Jeff has said: “These numbers represent a very small snapshot of the real safety of a boat and as such can be grossly misleading………….”

They say about the previous systems used for measuring stability (for ocean racing and used in Commercial vessels), the:

“RORC Triple S Numeral developed in the 1980s and the RYAs own STOPS number used for smaller MCA Code vessels since the 1990s start to approach the problem but both in a very rudimentary manner (nevertheless both are very successful).
It was from work on these two screening formulae that the ISO working group drafting the new stability standard developed its own stability index screen known as STIX. The RYA played a major part in this work..”

With a curriculum and a background like that, you can believe them when they say about the STIX system:


“STIX is arguably the most sophisticated stability screening tool yet available”


Jeff said:


“AVS suffers from another problem as well. As has been pointed out many times on this forum, there is no uniform standard for calculating AVS.”

I say:

This is not true, at least to boats sold in EU.

About the AVS, and we are talking about boats sold in the EU (including American boats), they all have to have their Dynamic Stability and Static Stability (the numbers that are later expressed in a GZ/RM curve that shows the AVS , and from where it is then calculated the STIX number) measured according to ISO 12217-2. This norm guarantees that all boats are measured exactly the same way, including specifications regarding weight taken from a boat in sailing condition, as defined by the rule.

Those measurements are not made by the builder but by independent, technical and very specialized private agencies holding a permit given by the EU that attests their independence and competence to do the job.

Obviously all the numbers of AVS and STIX that I have quoted in the previous post are all EU validated data, numbers that can be compared and that give reliable information on safety and stability of each boat.



Jeff said:

“key calculations and measurements were omitted from the standards because member nations considered them to be onerous. Instead simplified surrogate formulas were substituted for actual more sophisticated calculations resulting in very loose and sometimes missleading approximations”

I say:

This is, in my opinion, nonsense.

The Naval Architects and technicians that produced the stability requirements and the way to measure them were the most experienced in the field and based their work in the most meaningful work (and extended experience) on the subject, namely the RYA STOP numbers and the RORC SSS numeral system, both systems widely used with success for many years.


Jeff said:

Regarding to AVS and STIX numbers

“ None of these numbers take into account the weight distribution and buoyancy of the vessel in the inverted condition which can greatly alter the relative stability of individual vessels as the approach their limits of positive stability.”


I say:

This is not true.

As shown above the two first correction factors of the STIX are:

ability to withstand a capsize by considering the area under it’s GZ curve,

recovery from inversion by looking at it’s AVS and mass,

When you take into account the negative part under the GZ curve you are considering the inverted stability of the boat. When you consider mass and AVS in a recovery, you are considering global weight distribution. You are not considering only the weight of the empty boat( because all the data that permits those calculations were not taken from an empty boat), but the weight of a boat in sailing condition, as defined by ISO 12217.

Jeff said:

“An extremely high … STIX can be easily achieved simply by designing an excessively narrow boat with lots of freeboard , but with that excessively narrow beam and high tophamper, comes a greatly increased likelihood of a capsize or roll over”

I say:

This is not true.

As shown above the STIX calculation takes into account, besides length, seven different correction factors.

These three completely prevent that an easily capsizable boat could have a high STIX number :

ability to withstand a capsize by considering the area under it’s GZ curve,

displacement-length factor giving credit for a heavy displacement for a given length.

beam-displacement factor recognizing problems associated with topside flare and excessive beam.


Fact is that an easily capsizable boat, no matter its AVS, will always have a low STIX number:




Paulo
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Bluewater defined?

Paulo, that''s quite a lengthy post and I sure don''t have the time to dig into it chapter & verse...but I would like to offer one general observation. I think you place a huge amount of trust in the CE process, from when the draft rules were first created to how they are implemented today at a manufacturer''s plant, and as a result your points are building - at least to some extent - a house of cards.

These rules were heavily influenced by the manufacturers themselves, who participated extensively in the committee process, and were shaped for commercial concerns, and cedrtainly not solely safety-related concerns. Moreover, from personal experience I can assure you that a Notified Body, which is the entity that confirms ongoing compliance with the CE & RCD standards, is hardly the impartial body you describe. They are paid by the manufacturer, they have a commercial interest in continuing that relationship, and it''s much fairer to view this on-site inspection as an infrequent, imperfect, unfolding ''process'' than as some kind of absolute, non-stop compliance check. In fact, I''ll bet - admittedly a guess on my part - that a given Notified Body visits a given factory (e.g. consider a Bavaria, Beneteau or Jenneau plant) for perhaps two or three days in a two year period. One consequence of this is that these on-site compliance visits inevitably become paper & process checks and not nearly so much a real-world ''survey'' or inspection of the boats as built as the average consumer might imagine.

The RCD is a rating system which had as its original purposes the standardizing of build & trade practices within the EU and as a trade barrier to competition from outside the EU. That doesn''t make it worthless but it makes it far from an absolute guarantee of anything. IMO you are really inflating its significance.

Jack
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