STIX numbers

[dom]

Sorry I'm being stupid here ...get the bit about word count and to be honest Snooks reviews are great ...once one gets over his stowage fetish

But "STIX: xx.xx" = two words to me, two words!

 

[snooks]

Looking again at the Dufour 310 (simply because it is there, before us). The boat test reveals it is a Cat B design, this is unusual in itself because boats of this length are normally massaged into Cat A by canny designers, as already pointed out. A similar process to the "rule cheating" in racing.
Thanks to Barr Avel we know that the STIX figure is 33.22 and AVS 128.3. Very respectable for a boat of this size and in the RCD cat A range. However it is a Cat B boat. We can only assume that the "light ship" figures give us the flattering figures and the simple addition of a crew pushes the craft into the lower category. This is very useful information. My inference is that it is not a boat you would want to put mainsail reefing on or put unnecessary weight on the rig or, indeed, overburden with payload.

There could be another explanation but it is the ferreting out of the figures that begs the question.

There are many things in the RCD which could make her Cat B rather than Cat A, just a simple thing like guardrail height is enough - although the guardrails on the 310 were high enough IIRC. But yes in some boats you'll see Cat A6/B8 but there may be many points where she didn't make Cat A, there may be few. As you point out the STIX number too can be tweaked by certain design parameters. Which, although legal, might not be in the spirit of what the STIX was designed to do. So where does that leave us?

The same is true for RCD and how manufactures interpret it and how much they surpass the minimum requirement for the RCD. There is a manufacturer, that, in their brochure states their 31 footer is (and this is a direct quote) "The only boat in this size with CE Category A" It's not. I know of at least three other boats that are the same size or smaller with CE Cat A. (Winner 9, Hallberg Rassy 310, Legend 31) But the mfg has made their boat Cat A and sees this as a selling point - whether I'd take this 31ft yacht, or any other (except my Sadler 32) across an ocean is an interesting point.

It reminds me of something my driving instructor said to me. "I'm not going to teach you to pass your test. I'm going to teach you to drive." It's the same ethos with boats, some mfgs will make a boat better than the RCD, or STIX numbers dictate, others will supply what they need to, and so it questions the validity of these numbers and categories if they can be massaged to the shape the mfg want them.

I don't know the RCD or STIX number of my Sadler 32, and I don't care if she were to come out with RCD Cat Z or a STIX of 1, I know what I'm capable of, and I know her inside and out – although she does have a few peculiar wiring gremlins – but like the guy we featured in YM many years ago who sailed his boat from Seattle (IIRC) back to the UK, only to be told she was only able to achieve RCD Cat D when he came to sell her, all these figures need to be seen in context and, as we've seen with brass seacocks, don't always lead to the best building practices.

 

[snooks]

Sorry I'm being stupid here ...get the bit about word count and to be honest Snooks reviews are great ...once one gets over his stowage fetish

But "STIX: xx.xx" = two words to me, two words!

Two words yes, but as I said above Used boats don't have STIX, and we wanted to make used boats and new boats the same so each could be compared.

However as also I said, the format allows for 20 figures which take up 1/3 of the page:

Price £
LOA
LWL
Beam
Draught
Displacement
Ballast
Ballast ratio
Sail area
SA/D ratio
Diesel
Water
Engine hp
Transmission
RCD category
Designer
Builder
UK Agent
Tel
Website

Which do we lose to add STIX? Or put another way, which one is less important enough to be replaced by the STIX number?

OK so we add STIX and AVS we now have a list of two columns of 11, or one list of 22, which no longer fits into 1/3rd of the page. So we could reduce the photos on that page making them smaller with irregular proportions which limits the Art ed's choice of images, as they now have to fit in long thin boxes, not ideal. OK so we move the layout and profile up, but then again, the page is no longer balanced, so the design looks untidy and the photo opposite has to be moved up too. On the plus side this gives me more lines of copy, but then all the boxes in the Key Features start infringing on the image of the yacht....So we have less key features or I have to leave more space around the boat when I shoot.

It might seem like "two words", but it has a knock on effect within the design of the magazine.

And that's of course if we can get the STIX and AVS out of the mfg in time to go to print in the first place. :0)

 

[TangaraToo]

Which do we lose to add STIX? Or put another way, which one is less important enough to be replaced by the STIX number?

Ballast Ratio and SA/D Ratio.
Both very easy to calculate using the other information given.

 

[noelex]

Has any thought been given to making the boat reviews an extra page?

I realise this means giving up a page somewhere else, but the boat tests are a feature of the magazine and it seems a shame to skimp on detail in this important area.

 

[snooks]

Has any thought been given to making the boat reviews an extra page?

Oh yes, almost annually.

New boats (test and new boat news) account for between four and six pages in each issue - which seems fair given the feedback from our annual readership survey. Obviously I'd like more pages, but it goes back to trying to please as many people with one magazine as possible and getting the balance right.

While some find new boat tests interesting, other don't – I know it came as a shock to me too!

 

[dom]

New boats (test and new boat news) account for between four and six pages in each issue - which seems fair given the feedback from our annual readership survey. Obviously I'd like more pages, but it goes back to trying to please as many people with one magazine as possible and getting the balance right.

While some find new boat tests interesting, other don't – I know it came as a shock to me too!

No disrespect Snooks but I've heard that Scotland Yard quietly asked for your column inches to be cut -- I mean the Civil Guard almost had to be called out to quell the social unrest which followed your GT-35 review!

 

[noelex]

While some find new boat tests interesting, other don't – I know it came as a shock to me too!

But that is because you don't include the STIX number

Seriously, would a series of more detailed boat test rate much higher as a reason to buy/subscribe to the magazine? It would for me.

Perhaps some of the readership is expressing the view that in the current format new boat tests are not very interesting.

 

[Tranona]

Congratulations on the new yacht.

I too am in the process of looking for a new boat. My experience is different. Despite looking at boats on the expensive end of the spectrum there are areas where quality and best practice have been compromised.

Boats have to be built for a realistic price so some of the compromises are understandable, although for an owner that keeps the boat a reasonable length of time it would be cheaper to get the details right from the beginning. The use of brass rather than bronze seacocks is a classical example.

I don't believe the standards offer the buyer much protection. They set a very low base line. The fundamental construction of the boat is the area where the standards should should be most strict. For example, Without specialised knowledge a buyer cannot assess if the laminate thickness around the keel is adequate. Here the standards if they are going to achieve anything should protect the buyer and ensure a Cat A boat is fit for purpose as described.

There are failings of the standards even at this fundamental level. Look at the report on the Cheeki Rafiki for example. There are yachts with 100° AVS that have been certified as meeting Cat A requirements. Boats with spade rudders where the top bearing is secured to ply not even tabbed on to the structure etc etc.

The bottom line is do you trust a standard that allows the use of brass seacocks?

There are no boats with an AVS of 100 that would meet Cat A as the minimum is 120 - and most boats in the category exceed that comfortably. However, it is worth bearing in mind that many well respected older design boats would not meet Cat A if they were built now. I know of one design that in the first 20 years of its production run probably achieved more circumnavigations than any other single design - and yet needed substantial modification, including achieving the minimum 120 AVS when the builder certified it in Cat A.

As to standards and taking your example of hull thickness around keel attachment. The standards, both the earlier ABS and the current ISO are freely available and clearly show the minimum thickness - although thickness on its own is not a particularly good measure of structural integrity. It is interesting that the ISO was based on the ABS standard and was the result of significant work by the Wolfson Institute, but in most respects was little changed. You can find a good discussion on the standard and its application in the MAIB report on Cheeki Rafiki. Worth noting that the MAIB made no recommendation that the standard was inadequate, nor indeed that the boat was not designed and built to the standard with one relatively minor exception where the new standard had changed and the boat was built prior to the new one being introduced. There are of course other issues around the method of construction of that and similar boats, together with the way that they are used, maintained and repaired after damage. However that has been done to death on this forum already.

The point here, I think, is that despite all the doommongers there has not been a rash of modern boats foundering due to lack of stability. Most boats are used well within their capabilities and those of their owners. The handful of boats that have capsized in the last 30 years or so have almost all been in situations where no prudent skipper would want to be, and in many cases were easily avoided - that is the conditions were predictable and not just a case of being "caught out". Of course if one wants to habitually test the limits of conditions, survivability figures higher on the agenda, but for the average buyer it is of little interest as they never intend going there.

Much the same observation can be made about the use of plain brass for seacocks. Where is the rash of boats sinking? Why are insurance companies not refusing to cover such boats? The issue is very Anglocentric - European builders including such as HR have been fitting plain brass seacocks for years and literally hundreds of thousands are in use. Of course there have been cases of failures - although mostly fittings rather than valves, but hardly of epidemic proportions. It is wrong to think that builders used them just because the RCD set a minimum life of 5 years - they were in common use for years before that and I doubt any builders changed just because of the standard - bearing in mind that there was no previous standard. Builders fitted what they thought was appropriate and satisfactory.

All that is not to say that I don't support the fitting of more corrosion resistant fittings and valves, just pointing out that empirical evidence does not support the view that it is a major safety issue.

Getting back to the original point of where it is best to discuss these issues. Those of us with long memories will know that boat tests and reviews were much more comprehensive in the past, partly because new boat buying, particularly in the years before the economic downturn was a much bigger part of the boating scene. Indeed if you go back to the 60s and 70s there was a huge range of UK builders producing volumes of boats that you could only dream of now (in the UK at least) all vying for exposure and only too pleased to have journos crawl all over their boats. Nowadays new boat buying is very much a minority interest among private buyers in the UK as the feedback that Graham refers to shows. The majority of boat buyers now buy used boats and this is reflected in the magazine content where used boats get the same editorial as new.

So, I suspect the kind of discussion that happens from time to time here is really a minority interest. Indeed if you discount the "sensational" events such as Cheeki Rafiki the number of forum contributors to threads on new boats and design is very small, and often focuses on new vs old, perhaps because many of the contributors own "old" boats and few are in the fortunate position to buy new.

 

[noelex]

There are no boats with an AVS of 100 that would meet Cat A as the minimum is 120 - and most boats in the category exceed that comfortably.

There are many boats with an AVS below 120° that meet Cat A. Have a look at the magazine tests when they publish a stability curve, or at least an AVS .
This is the stability curve of an Ovni 385. It is Cat A:

The handful of boats that have capsized in the last 30 years or so have almost all been in situations where no prudent skipper would want to be, and in many cases were easily avoided - that is the conditions were predictable and not just a case of being "caught out". Of course if one wants to habitually test the limits of conditions, survivability figures higher on the agenda, but for the average buyer it is of little interest as they never intend going there.

The purpose of Cat A is to certify the boat for offshore conditions. This can and does mean voyages that are of longer duration than available weather forecasts.

You can find a good discussion on the standard and its application in the MAIB report on Cheeki Rafiki.

Yes the report is well worth reading. The hull construction around the keel was in my view inadequate. This boat met the Cat A requirements, the highest standard available. This is the fundamental problem with the standards. The bar is set very low. Buyers assume the standard ensures all boats that meet this requirement are suitable for offshore conditions. I think they would be wise to make their own judgment rather than placing a reliance on the standard.

 

[doug748]

There are many boats with an AVS below 120° that meet Cat A. Have a look at the magazine tests when they publish a stability curve, or at least an AVS .
This is the stability curve of an Ovni 385. It is Cat A:

.

Yes, there are a number of boats in this category. Without someone giving out the information we would all be in the dark.

PBO used to be very good at printing the full story, with a stability graph. Do they still do that, I must check it out.

 

[Tranona]

The purpose of Cat A is to certify the boat for offshore conditions. This can and does mean voyages that are of longer duration than available weather forecasts.


Yes the report is well worth reading. The hull construction around the keel was in my view inadequate. This boat met the Cat A requirements, the highest standard available. This is the fundamental problem with the standards. The bar is set very low. Buyers assume the standard ensures all boats that meet this requirement are suitable for offshore conditions. I think they would be wise to make their own judgment rather than placing a reliance on the standard.

The "bar" may well be too low in that there are many boats that way exceed the minimum requirements. However the standard was defined in terms of being suitable for waves of particular heights - not specifically for "offshore", however that is defined. Such conditions can easily be experienced close to land, and in fact many of the capsizes (if we want to focus on that aspect) occur close to land rather than in the open ocean.

If you look at the empirical evidence - that is boats that are successfully used in offshore conditions, you will find a huge variety of boats, many of which like the example i quoted earlier would not meet the minimum cat A. The Ovni you mentioned has an excellent reputation for offshore passage making despite its low stability. indeed there are some who are of the opinion that shallow draft boats like that are better in extreme conditions.

The important thing to understand about the RCD was that it was introduced to provide a common framework of regulations across Europe, rather than to provide definitive advice of the suitability of individual designs for specific uses. It would be impossible to devise a simple set of rules that satisfies everybody's views on what is suitable and what is not - even if you could get some form of agreement!

As to the keel structure of Cheeki Rafiki and without going over old ground, there are thousands of boats using that method of construction in use without any problems, including several hundred of that specific design. The number of failures is very small in relation to the number of boats in use and in most cases failure was due to specific incidents. There are clearly issues that need to be addressed, particularly in understanding how to repair damage, but the report did not make any recommendations about reviewing the standards, which one might have expected if there was serious concern raised in the investigation. It is also worth remembering that keel attachment failures like the poor have always been with us, but mainly in production boats used for hard racing or pure racing designs, rarely in pure cruising boats.

 

[doug748]

There are no boats with an AVS of 100 that would meet Cat A as the minimum is 120 - and most boats in the category exceed that comfortably... .

I am not sure about this, could you expand on it?

 

[Tranona]

I am not sure about this, could you expand on it?

Now I am not sure - I always thought it was 120. Most of the boats I have looked at are in excess of this. Must make the time to look it up.

Anyway, the point that I was making is that using an arbitrary single measure as a bar for suitability of a boat to undertake ocean passages is less than helpful when the empirical evidence - that is boats which have done this successfully shows that many of them would not pass that bar. STIX, of course is an attempt to provide a composite measure, but it is heavily influenced by LOA so excluding many small well proven designs. Taking these sorts of measures and then creating broad categories and the giving them labels that do not have a universal meaning creates the confusion that underpins discussions such as these.

I expect if there was a "Super A" category (what label would one give it?) there would still be the same arguments but at a different level. You only have to look at the thread further down this page on the ideal boat for ocean passages to see how little consensus there is about what makes a good boat for the job. What people choose is heavily influenced by the budget they have available and the choice of boats within that budget. This applies at whatever price range, old or new boat. Same dilemma at £50k or £100k or a new boat at £250k or £1m - or whatever. Statistics (and to an extent minimum standards) have little bearing on the choice.