Spe­cial

SATUR­DAY NIGHT

Boating NZ - - Front Page -

En­ter Al­lan Roper, the de­signer and builder of rac­ing yacht Satur­day Night Spe­cial, named after the Lynyrd Skynyrd song. A life-long yachtie, Roper grew up build­ing and rac­ing Cherubs and skiffs, and now in his fifties, he was keen for some­thing more sub­stan­tial that still got up and boo­gied.

Some years ago, Roper scored a Ross 930 mast, rig­ging and main­sail, and while he would have pre­ferred some­thing around 12m long, prag­mat­i­cally Satur­day Night Spe­cial was de­signed around this rig.

This meant be­gin­ning with a cal­cu­la­tor rather than a pen­cil, the rig’s size de­ter­min­ing the yacht’s length, beam and dis­place­ment. Fur­ther­more, Roper’s care­ful study of Bruce Farr, John Spencer, Des Town­son and Mur­ray Ross de­signs showed fast boats used a 5:1 ra­tio be­tween wa­ter­line length and beam.

An­other de­sign pa­ram­e­ter was the width of Roper’s shed, which lim­ited over­all beam to three me­tres max­i­mum. These num­bers pro­vided Roper with a self­im­posed box rule in which to draw the fastest, light­est hull pos­si­ble. de­signs, Roper had no hes­i­ta­tion opt­ing for ply­wood con­struc­tion – it’s light, easy to build, and when sheathed with epoxy, rel­a­tively long last­ing. It’s also bet­ter than most ma­te­ri­als from an en­vi­ron­men­tal per­spec­tive, be­cause at the end of the ply­wood yacht’s life it’s much eas­ier to dis­pose of than, for ex­am­ple, one built from GRP.

Roper based Satur­day Night Spe­cial’s con­struc­tion on Spencer’s well-proven stringer-on-frames sys­tem. The hull has nine yel­low cedar frames at one-me­tre cen­tres, sup­port­ing yel­low cedar stringers on 200mm cen­tres. The Mer­anti ply­wood hull skin is mostly sin­gle-skin nine-mil­lime­tre, with 6:1 scarf-joins backed up with butt-blocks. How­ever, the lower for­ward sec­tions are di­ag­o­nally planked in two skins of six-mil­lime­tre Mer­anti.

The re­main­der of the boat is also Mer­anti ply­wood, the rounded tur­tle deck is two lam­i­na­tions – one of six, the other of four – while the cock­pit and side decks are sin­gle- skin nine-mil­lime­tre. The whole boat is sheathed in 600-gram DB glass and epoxy.

As Roper in­tended to keep Satur­day Night Spe­cial on the poles at Sand­spit, shal­low draft was a ne­ces­sity, so he de­signed a ver­ti­cal lift­ing keel. The lift-keel’s case – which is ply­wood, sheathed in­ter­nally with 600-gram DB glass and epoxy – ex­tends up­wards from the keel­son to the deck­head. The keel came from a Mini Transat 650 that never made it to the wa­ter and is lam­i­nated from

Newspapers in English

Newspapers from New Zealand

© PressReader. All rights reserved.