Bosun Higgs
N/A
I'd be interested to know where you got those stix numbers from.
Which boat for Blue Water?
- Thread starter doug748
- Start date
I'd be interested to know where you got those stix numbers from.
doug748
Well-Known Member
Good, I am glad someone else is taking an interest.
The background I took from the RYA spreadsheet, available on the RYA site under:
Info & advice/Regualtions&safety/Stability data.
This is as interesting for the gaps, as for the information it provides.
I would love to know how come most of the Sigmas manage only Cat B? What makes the OVNI such a "seaworthy" design. Why is much of the data on Malo and Bavaria missing? What gives the Fishers an AVS of, wait for it,......180 degrees!
The information on the Nauticats I took from their website, the STIX figure was my guesstimate, based on a lead from an American design chat site.
The information on the Elan was from the recent article in Yachting Monthly.
Sans Bateau
Well-Known Member
I wasnt sure how provocative your original post was intended to be. It did, I suspect, not turn into the thread you expected, judging by your last comments.
STIX, AVS and ballast ratios dont get a huge exposure on the forums, but in the last few threads there has been a good conversation on the subject.
In response to your question, "is the STIX system potty or useful?" What do you think?
Incidentally, I had also been looking at the RYA STIX data, for another reason, about the time you made the first post.
STIX, AVS and ballast ratios dont get a huge exposure on the forums, but in the last few threads there has been a good conversation on the subject.
In response to your question, "is the STIX system potty or useful?" What do you think?
Incidentally, I had also been looking at the RYA STIX data, for another reason, about the time you made the first post.
scarebus03
New Member
As far as I'm aware Bavaria do not release their STIX values but obviously to be RCD Cat A they have to be minimum 32. The new Southerly boats have a high STIX value.
Brgds
SB03
Brgds
SB03
Blueboatman
Well-Known Member
Re Babylon
Quote -Can you explain this for me please? What is your boat? How small (length, displacement or category?) is the threshold at it would be 'illegal' for a French flagged boat to sail offshore? (I assume offshore means something like out of sight of land, 12 miles off land, and/or crossing from Cherbourg to Poole?)=quote
In France boats are deemed suitable for coastal or offshore sailing according to categories and inventory ( liferaft etc). And this is in law.
Typically there are many small boat owners having a smaller budget but wishing to sail anyway this year, without offending the authorities or waiting and saving for another 20 years to buy something with the correct category classification....So you sail off to the Caribbean ( say,)in your simple strong small boat that bobs along without fighting the waves, and then upon your safe return to Europe you arrive firstly in, say, Spain. From there one coast hops back to France.
Some would say that the current categories are actually a bit misleading and imply an assurance that ain't necessarily so for big new light sailing boats that sit 'on' the water rather than their narrower, more conservatively styled predecessors whose storage compartments were at least in part low enough down in the hull or keel or close enough to the centreline to actively contribute to the boats stability when laden for cruising. You might also be concerned about high freeboard, lots of large windows and inexpensively made spade (unsupported) rudders. On the other hand, at least in theory, mass produced boats 'should' have all the design problems sorted by the time they have built a few of them..Does that help?
Quote -Can you explain this for me please? What is your boat? How small (length, displacement or category?) is the threshold at it would be 'illegal' for a French flagged boat to sail offshore? (I assume offshore means something like out of sight of land, 12 miles off land, and/or crossing from Cherbourg to Poole?)=quote
In France boats are deemed suitable for coastal or offshore sailing according to categories and inventory ( liferaft etc). And this is in law.
Typically there are many small boat owners having a smaller budget but wishing to sail anyway this year, without offending the authorities or waiting and saving for another 20 years to buy something with the correct category classification....So you sail off to the Caribbean ( say,)in your simple strong small boat that bobs along without fighting the waves, and then upon your safe return to Europe you arrive firstly in, say, Spain. From there one coast hops back to France.
Some would say that the current categories are actually a bit misleading and imply an assurance that ain't necessarily so for big new light sailing boats that sit 'on' the water rather than their narrower, more conservatively styled predecessors whose storage compartments were at least in part low enough down in the hull or keel or close enough to the centreline to actively contribute to the boats stability when laden for cruising. You might also be concerned about high freeboard, lots of large windows and inexpensively made spade (unsupported) rudders. On the other hand, at least in theory, mass produced boats 'should' have all the design problems sorted by the time they have built a few of them..Does that help?
sighmoon
Well-Known Member
Does anybody know how the STIX values are calculated?
doug748
Well-Known Member
Good explanation (though not the formula itself) here:
http://www.troldand.dk/en/?The_Yacht:Stability
doug748
Well-Known Member
My motivation for the post was to be told a little about the STIX system. If you ask a plain question it tends not to stimulate debate, so why not post an extreme example:
1) A large comfortable motor sailer that most people would be happy to sail a long way in. Cat B ie Coastal
v/s
2) A small, fast inshore racer that most people would think twice about taking to the Channel Isles Cat A Offshore - Ocean passage
So the question is - How could the system come up with a result so at odds with "common sense" ?
There is usually no shortage of comment on all matters here, but people seem to either know very little about it, or be bored stiff by the subject.
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Sans Bateau
Well-Known Member
Whilst searching for interesting subjects to print in the pages of Yachting Monthly, IPC would not go far wrong in having someone write some articles on this sort of subject.
STIX has certainly created some interest on a couple of threads here, maybe if we had a good insight into the way STIX is calculated we would all be clearer as to why a CO32 has only a marginally better STIX than a Bav 32.
STIX has certainly created some interest on a couple of threads here, maybe if we had a good insight into the way STIX is calculated we would all be clearer as to why a CO32 has only a marginally better STIX than a Bav 32.
Bosun Higgs
N/A
I can answer a couple of your queries cos I investigated the numbers when I was havering between buying an Ovni and a Southerly or Vancouver pilot.
This comes with a health warming since its now 4 years ago and my memory is cr*p. In the case of the Vancouver, the AVS was a calculation by the designer based on some inclination data and the profile including the deck saloon which gives a sharp buoyancy increase when immersed.The same applied to the Southerly. Thats why I asked about the Nauticat cos I reckon it would have an official avs of near 180 deg. But whether or not to include the deck saloon seems to be up to the designer.
The OVNI I was looking at had a STIX below 32 but was still classified as A because it was a design from before the 32 threshold came out. In fact its stiffness was well below that of the Southerlies ( ballast in wrong place)
In the end I calculated the AVS of my wallet and settled for a second hand Moody. Wish now I had gone for the then new 35RS cos the offer at £130k all in was well below what I could now have sold the boat for.
The Sigmas long predate the STIX system so I doubt that you would find figures in the RYA list. However, if you talk to the RORC rating office I think you will find they have the numbers since the Sigma still is raced a lot.
Tranona
Well-Known Member
When the RCD came in there was a whole series of articles in the mags on the subject, explaing its origin (and the politics) as well as discussing the technical issues.
However, it seemed to die a death, perhaps because it is here to stay and there is little anyone can do to change it. If you are an RYA member, there are fairly regular reports on the subject, mainly around reviewing the categories, and of course there is good background on the site.
There are many more aspects to ther RCD than just design principles and the emphasis on stability and builders have learned to live with it.
The issue that comes up here most is whether the categories are a true reflection of a yacht's suitability for a particular use - mainly whether the standard (particularly stability) to meet Cat A is too low and does not discriminate enough the differences between larger boats used for extended passage making. This leads to calls for a "Super A" category for "real" Ocean ready boats.
However, there seems little call from consumers for such a category, perhaps because most are intelligent enough to differentiate between boats for themselves when making their choice. Likewise there seems to be little pressure from builders who might think their boats need a higher category, again perhaps because their customers aren't bothered. So Nauticat are quite happy with some of their boats in Cat B because it does not put customers off.
Where there is perhaps concern is at the other end of the spectrum, as in the Elan and Bavaria 32 situation where they are designed to just get into A. However, that will always be a problem with standards set according to formula. Designers (supported by their marketing people) will always try to manipulate their designs to take maximum advantage of the rules. We see it in Formula 1, Yacht racing, CO2 emmissions on cars and so on.
The problem for some people, particularly it seems those who advocate the advantages of particular designs (usually old) is the meaning conveyed by words. "Ocean" is used as a label for the highest category because it is where the conditions (mainly wave height) are likely to exist. However, for many Ocean has a very different meaning, signifying extreme conditions in remote locations - whereas in fact most ocean sailing is actually in benign conditions!
As to whether STIX is really of much interest to the average yachtsman - other than to debate the seeming anomolies it throws up is a moot point. As with all composite measures you need to look at the components because the same number can come from very different constituent measures. Just as the debate about the Bavaria and Contessa that got virtually the same "score" on the YM composite measure - but for very different reasons (size of heads compared with windward ability - both equally weighted!). At least STIX applies weighting - but even then weights are often subjective. In my previous life I did a lot of research into how groups made decisions in complex situations and scoring grids and weighting were often used to arrive at the "right" decision. However when the grid and weighting did not arrive at the "right" answer - the first thing was to re-visit the weighting!
However, it seemed to die a death, perhaps because it is here to stay and there is little anyone can do to change it. If you are an RYA member, there are fairly regular reports on the subject, mainly around reviewing the categories, and of course there is good background on the site.
There are many more aspects to ther RCD than just design principles and the emphasis on stability and builders have learned to live with it.
The issue that comes up here most is whether the categories are a true reflection of a yacht's suitability for a particular use - mainly whether the standard (particularly stability) to meet Cat A is too low and does not discriminate enough the differences between larger boats used for extended passage making. This leads to calls for a "Super A" category for "real" Ocean ready boats.
However, there seems little call from consumers for such a category, perhaps because most are intelligent enough to differentiate between boats for themselves when making their choice. Likewise there seems to be little pressure from builders who might think their boats need a higher category, again perhaps because their customers aren't bothered. So Nauticat are quite happy with some of their boats in Cat B because it does not put customers off.
Where there is perhaps concern is at the other end of the spectrum, as in the Elan and Bavaria 32 situation where they are designed to just get into A. However, that will always be a problem with standards set according to formula. Designers (supported by their marketing people) will always try to manipulate their designs to take maximum advantage of the rules. We see it in Formula 1, Yacht racing, CO2 emmissions on cars and so on.
The problem for some people, particularly it seems those who advocate the advantages of particular designs (usually old) is the meaning conveyed by words. "Ocean" is used as a label for the highest category because it is where the conditions (mainly wave height) are likely to exist. However, for many Ocean has a very different meaning, signifying extreme conditions in remote locations - whereas in fact most ocean sailing is actually in benign conditions!
As to whether STIX is really of much interest to the average yachtsman - other than to debate the seeming anomolies it throws up is a moot point. As with all composite measures you need to look at the components because the same number can come from very different constituent measures. Just as the debate about the Bavaria and Contessa that got virtually the same "score" on the YM composite measure - but for very different reasons (size of heads compared with windward ability - both equally weighted!). At least STIX applies weighting - but even then weights are often subjective. In my previous life I did a lot of research into how groups made decisions in complex situations and scoring grids and weighting were often used to arrive at the "right" decision. However when the grid and weighting did not arrive at the "right" answer - the first thing was to re-visit the weighting!
photodog
Lord High Commander of Upper Broughton and Gunthor
I dont think that is at odds with common sense at all...
That Nauticaat is a very nice boat... but a conservatory at heart... with the cockpit located very high.. in big seas she is not going to sail well... and you can only carry so much fuel... and that huge expanse of glass makes her very vulnerable to breaking seas... So I would not want to be out in her!
the Elan OTOH is a fine boat that goes well to windward... and activley sailed will probably be ok in a blow... the 2008 Fastnet... which saw some awfull weather.. had several modern light boats not dissimular (Ie Bene First's) of close size size do very well... She lacks most of the odvious faults of the Nauticat... and with a bit or preparation would be a better choice... in particular with a fairly strong crew.
I would still rather have the Rustler though thanks very much.
Tranona
Well-Known Member
Think you will find (as I noted at the beginning of this thread) that the Nauticat Cat B is not based on stability, but on the access to the wheelhouse being on the side rather than on the coachroof centreline. Does nt meet the downflooding angle for A.
tcm
...
A poster above comes close to mentioning catamarans, but then doesn't. Monohulls are for fab fun sailing. But "blue water" means that you're living on the thing. Stingo quoted a figure of sailing 1 day in 7 - i transat twice a year which takes a total of maybe 50 actual sailing days - almost exactly one in seven. The rest of the time I am interested in what it's like at anchor. So, I'm, at anchor flat and still , solid nights of sleep, loadsa space, whereas the mono's are lurching all over the place and living in a bucket. Or a very wam bucket if you ahave teak deck and dark blue hull - TK wisely wants someone *else* to buy that and let him come out for a day....
Oh and the nauticat rolls, urgh, plus big windows means it's great in northern waters, not if there's a palm tree within 1,000 nm.
Good option is what i'm hoping to do next year - take a catamaran and hook up with lightly barmy A35 racer to do the race weeks up and down the carib.
Oh and the nauticat rolls, urgh, plus big windows means it's great in northern waters, not if there's a palm tree within 1,000 nm.
Good option is what i'm hoping to do next year - take a catamaran and hook up with lightly barmy A35 racer to do the race weeks up and down the carib.
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Sybarite
Well-Known Member
http://www.prometa.fr/FR/PAGE_Cat45.htm
A 45' catamaran built out of heavy aluminium (Strongal). Not particularly fast but great for coral heads.
http://www.bretagne-info-nautisme.fr/Photos-du-Boreal-44-nouveau.html
If a mono-hull is called for. France's boat of the year - with inside bridge.
John
A 45' catamaran built out of heavy aluminium (Strongal). Not particularly fast but great for coral heads.
http://www.bretagne-info-nautisme.fr/Photos-du-Boreal-44-nouveau.html
If a mono-hull is called for. France's boat of the year - with inside bridge.
John