Genua convex ?

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NED1417
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Blev medlem: mån 24 apr 2017 12:03

Genua convex ?

Inlägg av NED1417 »

About Class Rules (Because we have no recent translation in English)

In the old English text of the Class Rules 2001 it says under G4. (Genoa);

G4.e; A convex leech is prohibited.

In the newest of Sweden 2019, that rule is no longer there. This means that it is allowed to make the leech convex, therefore, rounder (outside) than a straight line.

Is that correct?
Important in case of new sails to be made

Adri van de Velde NED1417

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maja
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Re: Genua convex ?

Inlägg av maja »

The thought is still the same...

But, talking to the sailmakers, we have learned that it is almost impossible to make a genoa sail with a convex leech. Maybe it will stand without flattering in very light winds, but already in light-moderate winds the leech will begin to flatter. So such a sail will be torn quickly due to continous flattering, and tensioning the lech rope will cause a considerable hook to occur.

Even a straight leech will flatter and hook when the wind speed rises. So sailmakers in general make the genoas with a slight concave leech curve for lightwind genoa sails and a deeper curve för strong wind genoa sails. Note that this is not special for the IF-boat genua, but for any foresail without leach buttons.

So, due to the above, it was decided to delete this requirement, as the sails, in practical, will not have convex leeches anyway... And, when it comes to certification, there will be one thing less to measure.. 8) ..

For the jib the situation is different, as leech battens are allowed and making it possible to have a roach.
Marek, IF-båt SWE-829 "Ingela" från Lagunen i Malmö
Medlem i IF-båtförbundet sedan 1985
IF-båtägare sedan 1983

NED1417
Inlägg: 12
Blev medlem: mån 24 apr 2017 12:03

Re: Genua convex ?

Inlägg av NED1417 »

Thx for the answer, it is not prohibited, that was the question.
I`m aware of the risk-off flattering.
The goal is making a light weather genua and that is already hard enough with the min. of 190grams.....

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maja
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Re: Genua convex ?

Inlägg av maja »

See Class Rules Drawings, drawing Nr 1328 - 6 2010-04-04 (Sail Measurement Rules).
For the Genoa-Jib it states: " Convex curvature is prohibited in the leech".
Marek, IF-båt SWE-829 "Ingela" från Lagunen i Malmö
Medlem i IF-båtförbundet sedan 1985
IF-båtägare sedan 1983

NED1417
Inlägg: 12
Blev medlem: mån 24 apr 2017 12:03

Re: Genua convex ?

Inlägg av NED1417 »

You're right. It's that you notice otherwise I wouldn't have seen it.

Btw, are there newer ClasRules in English than the version of 2001?

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maja
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Re: Genua convex ?

Inlägg av maja »

No later translation is made by us from 2001.

However, the German IF-boat club ( Hermann Klimberg, Irene Stützel and Knut Stützel) have made a translation into the German language.
See >>https://www.if-boot.de/images/dokumente ... eutsch.pdf

Unfortunately, they seem to have misunderstood the contents of Section B.4 ("Vergleichsmessung"). This fact has been alerted to them by us. But in general, the other parts of this translation is found to be correct.
Marek, IF-båt SWE-829 "Ingela" från Lagunen i Malmö
Medlem i IF-båtförbundet sedan 1985
IF-båtägare sedan 1983

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