Seaworthiness

Paulo,
I think that's not a valid argument.
Fishermen have been dying by the thousands through the centuries by going fishing in small open boats well into the ocean. As you know, they are not allowed to do that anymore (at least in Europe), in spite 'Dornas', 'Traineiras' and many other traditional designs being wonderful seaworthy small boats. Safety is always first nowadays.

Fascinating guy, that Diogo Botelho Pereira (he was a cartographer, wasn't he?). Here what Wikipedia says about him:

"Diogo Botelho Pereira é uma das mais obscuras e fascinantes personagens da gesta dos descobrimentos portugueses. Homem de temperamento exacerbado como no-lo dizem as crónicas que o referenciam, por causa desse temperamento fortes dissabores sofreu.

É feito absolutamente fantástico o seu de ter vindo da Índia ao Reino numa singela fusta, navio de todo improvável para realizar tão longa e tormentosa viagem, razão pela qual Dom João III a mandou queimar para " que não se vulgarizasse a ideia de que era possível fazer a viagem em tão modesto meio". São escassas as informações sobre a sua vida e as existentes muitas vezes levantam dúvidas..."

"Absolutamente fantástico" (italics are mine) could be considered as totally fantastic? (from the term 'fantasy'). It seems the guy had an exacerbated temper and his life is not totally clear. Mmmm....

By the way: Sensible man, Dom João III, burning the boat to avoid other crazy people trying to emulate that kind of adventures. Maybe he sent him to São Tomé and then to Cananor not to see him anymore.... ("D. João III nunca confiou inteiramente na boa fé de Diogo Botelho Pereira e acabou por lhe confiar a capitania de S.Tomé, onde adoeceu, acabando os seus dias na Índia como capitão de Cananor....") http://indispensaveis.blogspot.com/2004_07_01_indispensaveis_archive.html

Cheers.

 

Paulo,
More on Diogo Botelho Pereira:
"Mulheres em trajos masculinos acompanharam uma vez ou outra os seus homens até à Índia e em 1505 Iria Pereira seguiu António Real e foi mãe de Diogo Botelho Pereira, piloto e comandante da fortaleza de Cananor, onde faleceu em 1554." (http://www.historiadamedicina.ubi.pt/cadernos_medicina/vol10.pdf)
So it seems his parents were both portuguese.

And here what Dom João III wrote about him in a letter to dom Antonio d’Atayde, Count of the Castanheira:
"Vy a carta que me escrevestes sobre Diogo Botelho Pereira. Muyto vos agardeço os avysos que de suas cousas me daes. Eu escrevo ao governador que o mãde poer a Recado."
Translation: I saw the letter you sent to me on Diego Botelho Pereira. I thank you very much for the advise you give me on the things he does. I will write to the Governor for him to put him (Diogo) in jail" (It's OK, Paulo?)

As said: a fascinating but conflictive guy.
Cheers.

 

Have you taken in consideration that the boat is unsubmergible?

The STIX paper I have is from the long keel version. The calculated ML STIX is 44.7 and that is the STIX of the long keel version. The ML STIX of the short keel version is 44.9 (the MOCSTIX of the short keel is 41.3 and the MOCSTIX of long keel is 41.9).

The first time they had sent stability data to me they have said the stability of the two versions was the same. Not really true, but close enough to be negligible.

Edited: MOC and ML STIXs were swapped.

 

Nope, thanks!
That adds another 5 points, so bringing my numbers up to 43,91 for the MOC, which is closer to the numbers you post.
(by the way: are you sure about MOCs and MLCs in your last posts? Aren't they swapped? I understood 44.7 was for the loaded condition)

Now, if we take off the effect of the unsinkability, Valiant seems to have a better STIX (around 38) than Pogo (36.3 = 41.3 - 5). Now this is making more sense. Thanks again.

Cheers.

 

The nowadays somewhat compulsive pursuit of higher speeds (shorter time passages) for cruising boats has not only chosen the way of extreme lightness and big sail areas. The other way is also lightness and big horsepowers. Have a look at the Mandarin 52 (http://www.mandarin52.com/) or Powersail 15 & 20 (http://www.powersail.co.nz/index.html). In this last case big sail areas, too.
I confess I do not like this solution either.

 

About the argument, I don't agree. There is no absolute safety at sea, at least in what regards small boats. If it is not absolute it is a relative concept and therefore subject to personal judgment. On Diogo's opinion, the seaworthiness of his 18ft boat was enough for the job and he proved to be right.

About your interpretation of the Portuguese language, it is good, but not precise on this case. Absolutely fantastic was used here colloquially and in this context it does not relate to its etymology; Does not mean a Fantasy story, but means: An incredible feat, a real feat that is so great that is hard to believe in it.

We know that he has made that trip on that little boat, because when he stopped in Azores he had the bad luck to choose Faial for going ashore for supplies. He was trying to evade the Governor because he had been deported. He has chosen Faial, because normally the Governor was in Angra, but he was visiting the town and Diogo was brought to him. He managed to elude him, saying that he had a secret and very important information, to deliver only to the king and the Governor let him continue his voyage (I guess we was impressed too).

This encounter is a well documented one, and the only reason why in the end, the king believed that he had made that travel in that little boat.

About his origins (both father and mother were Portuguese), you are right. And with a mother like that it is not a surprise that the guy was courageous (his mother went to India as a sailor, disguised as a man , because she didn’t want to abandon her lover, the future father of Diogo).

 

Of course, you are right. I am going to edit that post.

 

Safety at sea is not absolute, evidently. As living is not either safe: we're condemned to death ....Seriously: The pursuit of safer boats and ships has been a constant trend since the first human being went sailing on a log, and has lead to numerous norms and regulations in all maritime activities, as you know. And those rules and regulations tend to be not subjective. On top of that, when you are obligued to comply with a norm, that becomes not subjective at all. Even on seaworthiness, an elusive matter, many efforts to quantify it on a as scientific as possible base have been done, as well as to enforce certain minimum levels. STIX is one example (As are structural norms, another important component of safety).

If you agree STIX is a good tool to measure seaworthiness (the best available, in your words), you have to admit it implies there is somekind of an objective approach to seaworthiness evaluation, and thus to safety. Talking on category A boats, a boat with an STIX of 50 should be intrinsecally safer than a boat with a 32 one, shouldn't it?

Cheers.

(P.S. See the correction of my post #599 on Valiant's and Pogo's STIXs)

 

Well, if it is unsinkable the delta factor is 5 and if we take out that from Pogo's MOC STIX of 41.3, we get an STIX of 36.3. That's not so high (In line with Beneteau 373) and not so far away from my estimated 38.475 (I confess I'm more confused now: which one is the mistake I make that leads me to estimate Pogo's STIX as being higher than the oficial one? Please, Paulo, scan and post the whole thing, even if it is for the MLC! I need to have a look at the thing to try find out clues!)

So, if we admit STIX is the best available tool to evaluate seaworthiness (or at least a nice one), may we say the qualified people that developed that nice tool think Pogo like boats are not that seaworthy/safe from a cruising point of view....? Are they wrong....? And if, on top of this, Eliasson, one of the four fathers of the STIX, thought category A should begin in 40 rather than in 32, may we (at least) be allowed to honestly have reasonable doubts on this boat as an open ocean cruiser...? And with that wide deck beam carried all the way aft, are we justified to think it may be even dangerous in certain circumstances....?

Cheers.

 

Of course, and a boat with a 92 STIX should be safer than a boat with a 50STIX. And what do this means? That we should stay safely on dry land unless we can afford a 140ft boat?

The disagreement seems to be about the minimums. For me the minimums are just that, minimums. If you want a maximum, you can go and buy a boat with a 100STIX, providing you can afford it and like to sail with a crew.

Do you really think that a boat like the Norborg 40 (STIX 34.5) should not be classified as a Class A boat? That it is not an oceangoing boat?

That seems odd to me. Of course, I understand that you personally demand for you a higher standard, but saying that boat has not the minimum requirements to be a class A boat, is a bit to much, at least in my opinion.

 

It is not me who suggests category A should begin at 40, but Eliasson, don't misunderstand me. I have repeatedely said relatively light, slender and bulbed boats (Like the Nordborg and others within the concept but somewhat heavier) may very well be the modern paradigma of cruising boats (without forgetting some other older paradigmas, still perfectly valid).

I agree with you that problems arise when judging the oceangoing ability of yachts with STIX in the lower figures of category A. It is very difficult to determine it when a yacht's STIX is in the 32 - 40 range, just judging by the STIX alone; and on the other hand it happens that some boats of proved oceangoing ability but with STIX figures under 32, are not A categorized. All this has been already thoroughly discussed at the STIX thread. It is such a difficult matter that there have even been knowledgeable people's opinions in these threads saying STIX is producing lethal boats.

It seems like we still need a better criteria to regulate seaworthiness than the STIX in it's actual form. We need (as I have been defending since the very begining of these debates) either to make STIX more accurate, taking into account other factors, like speed, inertia, dumping, negative/positive GZ curve areas ratio, etc, etc, as well as broadening the accidents/events database by a worldwide (huge) effort in acquiring more accurate data from real life, or then abandon and leave things to everyone's subjectiviness. (Or struggle for a new criteria system, but look what happens when we ask for ideas: See the several 'dead short' threads on the matter within this same Stability forum)

Cheers.

P.S: If you do not want to post Pogo's STIX calculation sheet in these forums, would you be so kind to scan it and send it to me by e-mail? I will greatly appreciate that, as I'm writing a conference on these matters. Address: g.gefaell<at>mundo-r<dot>com

 

And in a way that's the crux of the matter- for all the talk of seaworthiness and STIX, the fact remains that boats in general are pretty darn safe. When things go wrong it's usually the result of a multitude of factors coinciding, the crew are usually too busy trying to survive to collect useful data on the cause of the failure, and in the event of a catastrophic failure there's usually nothing left floating to study later on.
A car designer in the USA has access to a wealth of data regarding vehicle performance in fatal collisions- some 37,000 a year in his home country alone. And the wrecked cars can still be inspected to see what failed and why. A naval architect in the same country can draw on statistics from only 700 boating fatalities a year, most of which are the result of operator error or booze. With any given make and model of yacht, there will rarely be more than one or two incidents in total from which sound conclusions can be drawn. In the US at least, the boater is some 52 times less likely to be killed on the boat than to be killed in the car.
The result is that it's very, very hard to get a good statistical basis for a seaworthiness comparison. There are so many factors that must coincide for a boat to fail, failures are rare, and major failures often leave nothing left to analyse.
(Stats from the US DOT, Office of Hazardous Materials Safety, http://hazmat.dot.gov/riskmgmt/riskcompare.htm )

 

There you go again. Honestly, sometimes I don't understand you.

Guillermo, the Pogo cruising STIX is :MOC 41.3, ML 44.9.

Saying that the POGO STIX is 36.3 is just not right.

The STIX is the result of the integration of a lot of things relevant to the boat’s seaworthiness being one of them the unsinkability of the boat (or not). Even if you consider that a boat’s unsubmergibility it is not important for a boat's seaworthiness (and if you think so, I find it odd) you can not take that away from the STIX calculation, the same way you can not, at your will, not consider or modify any of the other criteria, even if you find that you don’t agree with those criteria.

If you do that we are not talking about the ISO STIX anymore (and you can not talk about STIX), we will be talking about a Guillermo’s proposal to alter the STIX calculation. When we talk about STIX, we talk about ISO certified STIX and that one is for the POGO (cruising version) MOC 41.3, ML 44.9., and that’s it. You have no right to say otherwise unless, as a citizen, you want to accuse Jean Marie Finot of having miscalculated those numbers and the certification body of wrongly have aproved the calculations.

About Ericsson (do you mean Rolf Eliasson?) he is only one of the many fathers of the STIX and it is obvious that the majority did not agree with him. I have to say that I have thought once along the same lines (about the minimum 40STIX for the Class A certification), but I have changed opinion. It makes no sense that boats like the Nordborg 40, with a STIX of 34.5 should not pass the certification for a Class A boat.

Saying that : “ STIX is producing lethal boats” seems to me absurd. Today boats are more seaworthy than 15 year old boats. If you compare Swans, Bavarias, Beneteaus actual Stability curves with the ones from 15 years ago, you are going to find a better AVS and an overall better stability curve.

 

Paulo,
Being unsinkability an important safety feature, of course, we still can take its effect out of the equation (it is as easy as imagining a Pogo with no watertight divisions), just to compare the influence of the geometry and weight related factors in the STIXs of two given boats. For analyzing purposes we may consider a non-delta STIX. Why not....? This kind of comparisons are absolutely fair and easily understandable, and widespreadily used in NA and other many fields. I do not see a reason for you to become aggressive again. I'm curious: is it a weakness in your personality? Are you the 'STIX's High Priest' or something...?

 

Matt,
I'm not talking just about statistical accidents reports, but also about getting data from a representative number of actual cruising boats, by installing aboard adequate sensors and a 'black box' for a period of time enough to collect data for the different types of boats (and crews!) in a variety of sailing conditions. Tank tests and CFD simulations have been thoroughly done, but a real life check would be great. The idea is not so collecting data from extreme situations like 180º capsizings or the facing of rogue waves (I do not wish that kind of situations for the collaborating crews in the program!) but rather the response and behaviour of boats under very variable conditions. I'm inclined to think there are a lot of B1 knock downs and losses of control out there (from all kind of yachts) that are never reported as long as they do not imply life losses or major breakdowns. It has to be, because of the laws of probabilities.

Technology is fully available nowadays and this has been done at least once by a japanese university, to my knowledge (I have to find the paper on the matter I posted somewhere before in these threads).

Cheers.