IOR landfills?

LordBooster

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spennig

Member
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New Forest
I think they were just starting to get elliptical rudders back then but did IOR optimization ever allow a bulb?

207 Bulb Keels. No yacht shall be measured, rated or raced under this rule if the width of the keel increases with increasing depth unless, in all sections, below the point at which the width starts to increase with increasing depth:
207.1 The keel can be girthed without hollows below the point of maximum width, and
207.2 A straight line connecting the outboard point on the lowest line of maximum width and a point on the centreline a distance equal to the maximum width above the point of maximum depth lies entirely within the keel.


IIRC, this was introduced at the Nov 83 meeting after no one could come up with a way to 'rate' Australia II style winged keels.
 

12 metre

Super Anarchist
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English Bay
207 Bulb Keels. No yacht shall be measured, rated or raced under this rule if the width of the keel increases with increasing depth unless, in all sections, below the point at which the width starts to increase with increasing depth:
207.1 The keel can be girthed without hollows below the point of maximum width, and
207.2 A straight line connecting the outboard point on the lowest line of maximum width and a point on the centreline a distance equal to the maximum width above the point of maximum depth lies entirely within the keel.


IIRC, this was introduced at the Nov 83 meeting after no one could come up with a way to 'rate' Australia II style winged keels.
I get the impression these provisions were mainly to eliminate anhedral wings like AII rather than bulbs as we know them.
207.1 is rather straightforward and a true bulb would meet the unless condition.
207.2 is a bit more convoluted but my interpretation is that it would take anhedral angle over 45 degrees to not meet the unless condition. My interpretation may well be wrong. If anyone has a better one, please comment.

Either way, it is likely IMO that a true bulb fulfilled the unless requirements of these provisions.

Steinlager II certainly had a bulb as designed in 1987. Perhaps this rule was relaxed for IOR IIIA.

View attachment 559329
See my comments above.

Interesting how often times old is new and designers get caught up in recent trends.

Steinlager II and Fisher and Paykel both utilized ketch rigs which had been abandoned in IOR for maybe 10 years or more. Mainly because sloop rigs on Maxis (beginning I believe with Ballyhoo) had proven their efficiency and worth in Round the Buoys racing. But IOR greatly under rated mizzen sail area, making them ideal if there is little upwind work - like in the Whitbread and ocean racing in general. They seemed to have forgotten that Sayula II (Swan 65 ketch) won the first Whitbread.

Speaking of Ballyhoo and old is new, Bob Miller's early IOR designs (Gingko, Rampage, Ceil III) were at their best in offwind racing and they had quite full bow sections. Not as full as todays scows, but no where near as pointy as most IOR designs. So it was long known full bows aid offwind sailing.
 

spennig

Member
120
76
New Forest
I get the impression these provisions were mainly to eliminate anhedral wings like AII rather than bulbs as we know them.
207.1 is rather straightforward and a true bulb would meet the unless condition.
207.2 is a bit more convoluted but my interpretation is that it would take anhedral angle over 45 degrees to not meet the unless condition. My interpretation may well be wrong. If anyone has a better one, please comment.

Either way, it is likely IMO that a true bulb fulfilled the unless requirements of these provisions.
I agree, it's convoluted but it allows conventional circular bulbs. The intention was to disallow AII style wings. Anyone who "enjoyed" short tacking one of the later CHS winged "Collins" keels, e.g. along the muddy N Solent shore, would appreciate that. Touch, tack, suction, stuck. Better hope the tide's rising.
 
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DickDastardly

Super Anarchist
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Syderney
207 Bulb Keels. No yacht shall be measured, rated or raced under this rule if the width of the keel increases with increasing depth unless, in all sections, below the point at which the width starts to increase with increasing depth:
207.1 The keel can be girthed without hollows below the point of maximum width, and
207.2 A straight line connecting the outboard point on the lowest line of maximum width and a point on the centreline a distance equal to the maximum width above the point of maximum depth lies entirely within the keel.


IIRC, this was introduced at the Nov 83 meeting after no one could come up with a way to 'rate' Australia II style winged keels.
It’s hard going but in my reading it doesn’t prevent regular bulbs.
 




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