Goolwa Radio Yachting Group

Phantom Specifications and Modifications

Click for sail numbers already issued for phantoms

Please note these are current ideas for defining variations within the Phantom yacht

There appears to be no detailed specifications that define the Phantom RC sailing yacht.  From discussions with our group t a standard set of guidelines about what can and can't be modified on the yacht have been determined.

• The hull should remain essentially as supplied by the manufacturer and re-moulding the hull in glass or carbon fibre etc would be not acceptable.

• The fin and rudder should remain as supplied by the manufacturer though if broken may be remade in timber, glass, carbon etc to the same dimensions and shape, matching the airfoil as closely as possible.  Replacing the rudder with a larger one is highly desirable for control and balance of the yacht and should be considered as an allowed option. The rudder may be repositioned further aft vastly improving control

• The ballast container may be replaced by a lead bulb whose max weight is ~2000g and whose vertical dimension is no greater than the original bulb. (Almost impossible to get 2000g in original bulb but is essential to get performance.  The bulb needs to be moved aft to prevent nose-diving as weight increases.

• The mast should remain as supplied by the manufacturer.  If broken this raises a problem of resupplying a mast of the same section.  It may be necessary to allow some replacement in the future but for now breaks can be repaired using a joiner similar to that supplied by the manufacturer.

• Booms may be replaced if broken though the main boom is quite strong.  If replaced then the boom lengths should not exceed those supplied by the manufacturer.

• Booms and vang may be modified to allow the vang to be adjustable and the boom to pivot at the gooseneck as it improves the setting of the sails and makes their adjustment much easier for skippers.

• The main sheet winch may be replaced by the same or similar model as they are available through model suppliers.

• The steering servo may be replaced with standard servos available at model shops.

The sails form a special case as those supplied by the manufacturer vary so much in quality and efficiency that modifications are a necessity in most situations. There are however statements made by the manufacture about the sail area being 0.4 m².  From calculations from a number of yachts this is the triangular area of the main and jib.  The triangular area is defined as the luff multiplied by the foot perpendicular (minimum distance from the clew to the luff) divided by 2.  Any modifications to the existing sail must not enlarge the existing sail but should allow for reshaping of the luff.  Seams can be used for additional shaping and battens may be used to assist setting of the sail.   Both the mainsail and the jib have a significant amount of roach whose area is not measured in the 0.4m².  Sails may be replaced but must conform to the maximum area above, made of a single piece of material and must fall within a standard set of dimensions.

Sails can be produced or purchased  meeting the following max dimensions  and can now be shaped with seams if desired.  Cut-down Mylar IOM sails is one way to go and perform well

Mainsail -  Luff: 1255mm, Foot perpendicular: 350mm, 3/4 point:163mm, 1/2 point: 250mm, 1/4 point: 313mm
Jib -  Luff: 1140mm, Foot perpendicular: 315mm, 3/4 point: 99mm, 1/2 point: 178mm, 1/4 point: 246mm.
The 1/4, 1/2 and 3/4 points define the max roach at those points.  The roach may be drawn in a smooth curve to pass through these points.  These dimensions define the area of the sail as 0.3992m² which lies within the dimensions of the supplied sail.

If in doubt about these dimensions then the sail outline must fall within those of the original sail.  NB this means that smaller sails may be made and used providing they meet these criteria.
NB sails MUST carry clearly visible numbers to identify the yacht. See Sail Identification document for size and position of numbers.  Sail numbers need a contrasting colour to be visible particularly on the dark blue jib.  Considering this difficulty, numbers only on the mainsail will be accepted.

• Fittings attached to the mast, booms and deck may be modified to improve their strength, assist in the setting of the sails or sheets.

• Shrouds may be replaced by better quality cord or wire.

• Deck modifications to reduce the ingress of water through the hatch area are acceptable.

• The steering mechanism including the servo, rudder posts, rudder steering arm etc may be modified to improve the handling of the vessel.

• Sheeting guides to direct the main and jib sheets are acceptable.

In general, other modifications are acceptable if they do not essentially change the yacht or its dimensions but improve its handling and seaworthiness.

page last edited on 08/09/2020