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Reply to: The annoying questions begin - (Nacra 5.2)

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[quote=erice]i always have problems finding this as it's in the technical gallery and i expect to find it in the downloads

it is downloadable pdf file of the nacra manual about 1985

it is earlier than the one on the nacra site which seems to be about 89-91

http://www.thebeachcats.com/performance/Nacra-printed-1985a.pdf

the 5.2 was made from 1975-1987-??? which were pretty much the glory days of beachcats and it went through quite a few changes before it was eventually replaced by the lighter/longer/wider/more sail area, nacra5.5

(the 5.5 being lighter than the 5.2 meant that nacra sold it in 2 versions. 1 for solo use without a jib and the other with a jib for crewed use)

one of the major changes over the 5.2's production life was the mast spreaders going from straight to swept

straight spreaders meant diamond wires, which allowed control of the mast's sideways bend characteristics. mast bend control in conjunction with mast rotation control  was at the time considered an important tuning option. BUT rotating the mast to anything less than the ideal aerodynamic position seems to have cancelled out any benefit achieved by controlling the jib slot size

so when in the early 80's the tornado guys discovered that by raking the spreaders and really cranking on the downhaul they could bend the mast backwards and depower the sail more efficiently than releasing mainsheet straight spreaders were history

pretty soon all the cat makers changed from straight spreaders to swept spreaders and redesigned their sails to cope with the huge downhaul forces required

so if you have a straight spreader 5.2 ignore all the books that say to depower the sail by hauling on downhaul. the stock downhaul system won't give enough pull and the stick sail won't cope with 15 to 1 systems  [email][/email]<em>edited by: erice, Jul 09, 2009 - 03:31 AM</em> [/quote]

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