Phigit class

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The Phigit class was developed by Charles Détriché, Graham Bantock, and Lester Gilbert in 2006 with the support of Marine Modelling International under the editorship of Chris Jackson.


Class concept

From the Class rules forward:

The Phigit class is intended to provide opportunities for non-professional builders to design, develop, and race a radio controlled boat with very few restrictions to the hull and radio control equipment, while exploiting the free availability of sails, rigs, and appendages from the popular and established IOM class. Owners and crews may note that:

  • The two gauges (depth restriction, vertical centre of gravity) used for measurement control may be easily constructed, allowing an owner to carry out simple self-checks of rule conformity.
  • Sails may be certified either by an official measurer, or by the manufacturer if approved by the Class Management Group.
  • A boat may be issued with a certificate following an owner’s self-declaration of the measurements required on the measurement forms.
  • The major measurement controls of the boat are carried out at an event.

The late Angus Richardson provided a simple chine Phigit design, Arachnid.

My interest in the class derives from the four key ideas listed above, to see if they could be made to work, and to see if they might have some application to other radio sailing classes.  If they can work, they promise a profound simplification to the business and pleasure of racing classes with such rules at sanctioned events.

Depth restriction

In order to check the draught of a boat, it normally needs to be floated in a tank which has some convenient means of determining the distance from the water surface to the bottom of the keel.  Such tanks are time-consuming to build, awkward to fill, and difficult to transport.  The idea here, borrowed from the Marblehead class rules since 2003 or so, is a much simpler way of checking keel depth.


Vertical centre of gravity

After a class has decided upon the boat's draught, the most important aspect which many of the rest of the class rules constrain is the boat's vertical centre of gravity -- what materials can be used where, what weight can be positioned where, and how much of any of these things can be used.  Everything a designer does is intended to lower the boat's CG so that its righting moment is maximised.  The idea here, borrowed from full-size, is to do away with all the rules concerning materials and weights, and have a simple vertical centre of gravity limit instead.  The boat passes this VCG test if it balances on the gauge or if the hull side tilts down, otherwise it fails if the ballast side tilts down or if the boat falls off the gauge (ie it cannot be balanced, meaning that the CG must be somewhere on the fin).


Sail measurement

The third innovation in the measurement control of a boat is to allow the sailmaker to certify the sails.  An official measurer can do that as well, of course, but what is simpler than permitting the sailmaker to certify that what has been made meets the class rules?

Owner declaration

Once all the key boat measurements can be easily checked by the owner, it then makes sense to issue a certificate based upon an owner's declaration of conformance.  Of course, the boat must still be checked, since not all owners are scrupulous about refitting their battery packs in the same position they were when the VCG was first checked, or having certified sails.

Checking at an event

Because of the simplicity of checking the key boat measurements, this is now done at an event.  No need to make an appointment with an official measurer some miles away at some cost to both the owner and the measurer, and no need to lodge any measurement forms with a class secretary or registrar.

Phigit in Italy

Salvatore Cuomo ("avel30" at "yahoo" dot "it", you know to replace the "at" with "@" and the "dot" with ".") took over the class management for a while, and ran some events.  Thanks Salvatore!  Sadly, his site at no longer works, so I am re-hosting the Phigit class documents for the time being.

©2022 Lester Gilbert