Seaworthiness

Hi Folks,

On somewhat the same theme, I've started a thread in Sailing asking for opinions and experience with seaworthy headsail combinations.

I'd welcome the insights that the folk in this thread can provide.

Seaworthy Headsails

Thanks!

Randy

 

The pic on the right ("our" pic, ie the one we've been talking about for a while) can't have been 1993, because I have a solid copy of the 1987 Seahorse Admiral's Cup programme which definitely shows the boat in the pic.

There was no "Jameson Whiskey, (IOR 50)" in the 1987 team - there was Irish Independent Full Pelt (Dubois 40 1 ton); Turkish Delight (Castro 43) and Jameson Whisky, another Dubois IOR 40 1 ton. It's the latter that is clearly boat in the pic on the right.

I'm not at home, because a blown water main destroyed our phone and internet connections, so I can't scan that Seahorse. It goes into a few pars about how the boat was re-keeled for better upwind performance. It didn'
t do the trick because the Seahorse report ont he AC refers to it as a one tonner and says that it was "particularly disappointing upwind in the inshores". The boat is also listed in the results as a Dubois 1 ton.

Sorry, but there's no doubt it's a Dubois 40 1 ton.

I may have the '93 AC programme at home (or it may be in storage). I think the red boat may have been the Australian-owned Farr 50 Heaven Can Wait.

 

Thanks for that. Between my rickerty old brain and a mis-labelled website, I was getting confused. But it doesn't take much.

Now, where have I left my car keys / jacket / mobile phone / etc, etc...

 

These figures are very hard to read. Is it 3,048 m?

1,340 knots or 13,400 knots?

4,035 or 4,350?

you need to correct these!

 

hmm, djwkd, since when does thousands consist of only two digits after the comma?

It's a comma, and although americans use the "." – acting all backwards and unaware of the metric system, it ought to be understandable - especially seeing that there are only two digits.

So, it's 13 knots, and 40/100ths.

Noone needs to correct anything – except for the americans, and as that isn't going to happen soon, maybe just a little common sense and basic metric (al?) knowledge would go a long way.

 

The comma as a decimal separator is used in several continental European countries, including Germany, Austria, Switzerland, Belgium, Luxembourg, and - we think - also Italy and the Netherlands.
The notational convention of using a punctuation mark to separate the fractional part of a number seems to have begun with John Napier,a Scot, in his book "Descriptio" published in 1616. In this book he proposed using a decimal point (period) to separate the whole number part from the decimal part of a number. In the following year, 1617, in his book "Rhabdologia" he proposed a point or a comma as the decimal sepatatrix. In his writing he used both. To quote Cajori, "Napier vacillated between period and comma; mathematicians have been vacillating in this matter ever since", Florin Cajori, "A History of Mathematical Notation", 1974 page 324. By 1619 the decimal point had become standard in England.

Edit: quoted from a blog.

 

DB
Since when are knots metric? And for your superior European intellect Newcastle- upon-Tyne is in England, which does use the metric system. Its about commas and nothing else. It is confusing for someone who has never used or seen them used in that way.

 

Well, if people have never seen them, maybe it's about time.

Most of the world uses the metric system, so noone needs to "correct" anything in order for americans to udnerstand the basics. I will go as far as using feet/metres with one or the other in a parenthesis, but there should be no need to not use the metric system because some is confused by a comma instead of period – especially not when in order to misinterpret the metric system, he even moves the punctuation.

Even though knots aren't metric, one and a half knot, will be written 1,5 or 1,50 knots. Type it into your calculator. You would take one knot, and multiply it with? Yup, that's right.

Let me make myself perfectly clear: It shouldn't be necessary for everyone else to cater to anyone, merely because he is unaware of what the rest of the world uses. I find it ever so arrogant to even suggest something like that.

 

Once again...this IS an American explaining to you that it was a Brit that you were ranting about. And yes, arrogance is an issue here, just not where you think.

 

DG - it doesn't make it any better that it's a british fellow. That is even worse. And it hardly changes much.

Arrogance certainly comes all over, DG, but you would be hard pressed to find it arrogant that I _oppose_ using an american standard (no matter if it's a brit saying it) because some guy is ignorant about the metric system.

What do you suggest then? That we should cater to the lowest common denominator, because there might be someone out there that doesn't understand? Someone who, in this instance, are even moving things around, in order to make it even less likely for the person to understand?

I might have jumped too quickly about the americans, but then again, most people I meet who cannot understand the metric system are americans - and most americans I meet can't understand the metric system.

- Which is rather odd, if you ask me, since the monetary system is metric, percentages are metric and so forth ...

 

The 10th resolution of CGPM (General Conference on Weights and Measures) in 2003 declared that "the symbol for the decimal marker shall be either the point on the line or the comma on the line".

In practice, the decimal point is used in English, and the comma in most other European languages.

As I'm spanish, I tend to use the comma. But I have not problems at all in using periods, as I have also done in these forums. Just whatever is more convenient for the general understanding. For the time being, you're the first one to point this out, to my knowledge.

Cheers.

By the way: knots are speed units accepted for use along with the SI. See: http://www.bipm.org/en/si/si_brochure/chapter4/table8.html

 

If we are to be universally understood when we speak of measurements, it is best to stick with SI units. (http://en.wikipedia.org/wiki/SI_units for reference). Since we are dealing with boats, I would think the nautical mile and the knot are also acceptable; feet and inches may be used if that's how the boat was originally designed and sold. Nobody should be confused by this.
Arcane units such as the furlong, fathom, long and short tons (best to stick with 1 t = 1000 kg), gallon (unless you specify what type of gallon), etc. should be avoided if we want everyone to understand us, regardless of location.
Separating groups of digits is best done by spaces (eg. "12 000 000: for "twelve million") as using a comma ("45,005") could be read as "forty-five thousand and five" or "forty-five and 5/1000".
To the Americans- if you see a comma in a number, read it as a decimal point and move on. Both punctuations are in common use worldwide and there really is no difference.

 

The thing about all this is that no matter what, there was no need to confuse matters as DJ did - he moved the punctuation both ways and added a zero instead of merely thinking of a period. That's like saying: ""20,5 centrigrades" I don't understand that – do you mean "205" or "2.05"?"
Ridiculous.

Edit: WHat I am saying, is that this wasn't about using a period or a comma, it was a statement saying it was wrong to use whatever, and the "proof" was shown by adding a zero.

 

To convert other units to the SI:
http://physics.nist.gov/Pubs/SP811/appenB9.html

 

Just to come back to this thread's main purpose:

From a B. Deakin article at "Sailing Yacht Design: Practice" (Claughton, Wellicome & Shenoi, 2006 edition):

"Claughton and Handley ("An Investigation into the Stability of Sailing Yachts in Large Breaking Waves", 1984) present data for a selection of yacht forms which were studied using model breaking wave facilities. The tests revealed that narrow forms were a little bit less vulnerable than wide forms, being propelled sideways without sufficient inmersion of the deck edge to cause capsize in waves that would capsize wider models. This and other differences were eliminated by encounters with slightly higher waves however, and it proved possible to capsize all of the forms tested.

Independently other researchers reached similar conclusions and it has been concluded that there is little to be gained in attempts to reduce vulnerability of monohulls yachts to capsize. The important consideration is to ensure that a capsized yacht returns upright after the breaking wave has passed. To this end the yacht requires sufficient range of possitive stability, to right herself in the prevailing seastate. A range of 150-160º was suggested after finding that yachts with lower ranges could be left inverted after passage of a wave.

Many traditional cruising yachts had a range in excess of 150º, but that is rare for contemporary forms, and some of those who favour particular types of modern yacht designs put forward arguments against the requirement for a large range. At the "Safety from Capsizing, Final Report of the Directors" (USYRU & SNAME, June 1985), concluded that, to limit the time that a yacht would remain inverted to about 2 minutes, a range of 120º is required, and this formed the basis of their recommended minimum range, with more stringent requirements for yachts less than 12 m in length. In the UK, recommendations made by the Wolfson Unit to the Department of Transport also proposed a linear variation of minimum range with length. The proposal was adopted in the Code of Practice."

This Size-AVS approach was also used for ISO 12217.