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Producing a 'B' rig for the Phantom

Rudders Chain Plates Mast fitting for shrouds forestay Mainsheet fairlead Water proofing the hatch Improving Ballast Replacing Shrouds 'B' rig sails Radio Setup Clew/Tack Adjustment Improved sheeting system Gooseneck repair

These sails certainly allow the Phantom to sail in conditions where normally the yacht would wallow and be very difficult to control.  The yacht is sailable to 20+ knots and under control at all times.  The rig suffers against the full rig in winds below about 8 knots - holds its own at 10 or so knots and starts to become a winner above that.
 

The members have now produced about 15 'B' rig sails for the Phantom.  These are about 75% of the area of the standard rig with their average area much lower than the standard rig and allow the phantom to sail in winds up to about 18 knots or so.  Note that in keeping with the specifications of the sails for the phantom, no seams are used just a flat sheet of Mylar film (50 micron).  The dimensions of the sail are based on the standard rig with the foot of both main and jib being about 10 mm less than the standard rig and the luff measurements 75% of the standard rig.  I will give these dimensions more accurately soon. 

The process of producing the sails involved drawing out the shape of the sails on stiff paper, taping this to a bench and laying the sail cloth over the outline, transferring the outline to the Mylar film other than the luff then drawing a curved luff with a flexible wooden stick.  The luff curve was made about 5/6 mm for the main and about 3/4 mm for the jib.  These correspond to the accepted value of about 0.5% of the luff length (assuming a mast which is not very flexible).  See photos in 'Images' menu

The luff is taped with 8/10 mm Mylar tape on both sides while the foot and leech taped with 4 mm Mylar tape on one side.  This helps prevent the Mylar film from tearing, supports the luff and help develop a little shape in the sail when the leech tape shrinks on release ever so slightly.

The result is a set of sails that are aerodynamically clean and efficient.  This is evident by the way the Phantom continues to drive in the stronger gusts yet remain competitive against the original sails to 8 knots or so, becoming clearly more effective above 10 knots.

See Photos and videos of 'B' Rigs in action in gusts over 20 Knots at

 https://picasaweb.google.com/114231195882915542478 and find album 'Phantom B Rig in action'

Attaching the sails for quick change

I will outline methods of rigging these sails below to make sail change quick and easy.  The key thing here is to make the change of sail easy to do so it can be done quickly.  This means that the sails need to be able to be removed and replace readily and maybe the jib sheets attached easily. 

Looking at the mainsail first it makes sense to leave the boom where it is and have an easily removed clew, tack and head attachment.  Richard's clew attachment is the simplest (see clew/tack adjustment heading at top of page) while Ben's method see same page is also fast and give complete adjustment.  The tack is easy as the original line will work tho again Ben has a way to improve this at least for speed of changing.

 The head also can use the original phantom method tho feeding the line through the small hole on the fitting is fiddly.  A small permanent ring attached to this point can make it easier to feed the cord through.  Feeding the sail with its slides into the sail track requires either removal of the masthead fitting or perhaps better, filing away the top 12-15 mm of the track from the mast so the sail slides can be fed into the track without removing the masthead fitting (and rigging!).  see picture at right

The jib is most easily set up on a new separate boom.  An arrow shaft or carbon fibre tube from model suppliers (~6mm is best) is the best option.  In this way, the sail can be permanently setup with tack and clew adjustments similar to the ideas in.  The forestay needs attaching to the mast using a hook in a 1mm hole somewhere just above the mast joiner.  The jib sheet attachment is most easily done by making a loop in the end of the sheet and having a sliding fishing fitting attached by a short strop to the boom using a cable tie.  See the clew/tack adjustment pages for images and more description.

 

 

 

page last edited on 13/05/2012