Plan B

International One Metre Racing Yacht

SHOWCASING - PLAN B - A HIGH PERFORMANCE IOM RACING YACHT FOR COMPETITIVE RC SAILING

DESIGN

Plan B is the culmination of more than three years of development, sailing with the very competitive Paradise Radio Yacht Club at Emerald Lake and at regional events in Queensland Australia.  We are fortunate, with our climate, in being able to sail throughout the year in varied conditions and in a full range of wind strengths.  The design is the third version of the concept, each version requiring a complete set of hull moulds.  Twelve yachts were built and evaluated before Plan B was offered for sale. 

This photograph shows one prototype, # 128, racing at the Eddie Cowell Regatta, Kawana.

 

The easily driven, chined hull has a long, fine entry to elliptical sections in front of the keel, a shallow Vee aft into a straight run at the rudder.

It floats bow-high at rest and uses the dynamic lift of the forward sections together with Bernoulli Effect from the aft sections to maintain this attitude downwind at speed.  The fine entry minimises 'tripping' and burying the bow.

When heeled, the hull presents a straight run with narrow cross sections.

The concave, raised fore-deck closely follows the jib-boom and positions the mast ram for effective mast control.

There is a large central hatch, recessed to be flush with the deck, for ventilation and access to the rudder servo, receiver, battery, switch, wiring and corrector weight.  This hatch gives adequate ventilation, without the need to remove the rear deck patch.  The layout is convenient and practicle. 

If needed, the flush, deck mounted RMG switch can be circumvented by simply exchanging the installed XT-60 plugs.   The waterproof Hitec HS-5646 WP, digital, precisely self-centering rudder servo and the RMG 290 EF winch can be removed and changed through the main hatch, without removing the rear deck patch. 

The rudder shaft, stainless steel tiller and also the winch are readily accessed through the rear deck opening, covered by the rear deck patch.

The winch, rudder servo, battery and corrector weight are placed to suit the hull displacement; alongside and behind the keel.

Above-deck RMG 32 mm. self-tensioning winch drum and lines give quick and easy access and no water ingress.  Sheets, winch drum and lines can be changed from outside the hull.  The winch drum is shielded with a smooth, rounded cover.  This drum and the Hales deck mounted, ball-raced deck blocks can be readily flushed.

The keel, ballast and rudder have fine entry, low drag laminar-flow sections.  The narrow keel profile is constant to give torsional stiffness.  The rudder profile with tubercles allows an increased angle of incidence before stalling, to improve steering and minimise drag.

Ballast centre-of-gravity is positioned at a calculated measurement forward of the keel null point, to give wash-out under heeled load.  

 

Plan B was drawn using engineering CAD.

Parameters were calculated and extensively checked before construction.

CAD enabled, for instance, the displacement distribution, wetted surface area and prismatic coefficient to be ascertained and optimised at incremental angles of heel.  The result is a well balanced yacht that can be readily trimmed to 'hands-off' sailing.

Plan B is an attractive yacht, both on and off the water.

A PERFORMANCE IOM DESIGNED AND BUILT IN AUSTRALIA BY PETER BURFORD
"Everyone needs a Plan B"