Technical & theoretical aspects of RC yacht racing

Updated May 2025

I'm interested in radio-controlled racing yachts.  I campaign a fine wooden hulled Ravenna in the UK 6M class, shortly to be joined by an equally fine Romanza, both Bantock designs.  I have acquired a 36R Raptor and sail it approximately annually.  For some while I sailed in the International One Metre (IOM) class, most recently with a Pikanto, and hope to return 'real soon now'.  Previously I campaigned an Italiko IOM, and before that an Ikon, highlights being various mid-fleet placings at European and World championships.  In other classes, I have sailed a Marblehead Quark, a 10R Puzzle, and vane-sailed an A Class and a 36R.  For some years I also campaigned a Sword A Class, my highlight was 9th place in the World Champs at Gosport in 2005.  My "Bakers Dozen" A Class, built by Graham Bantock in Kevlar to Roger Stollery's design from 1983 and the RA National Champion of that year, has gone to a good home in Norway, courtesy of Øyvin Halle.

This site is aimed at technical and theoretical aspects of RC yacht racing. In particular, it has a number of spreadsheets to download. Although aimed at the IOM, they should be useful for any non-rotating fractional Bermuda sloop rig.

Site news & other interest

May 2025:  3D-printed boom band -- STL files for 10 mm Ø and 12 mm Ø booms.

May 2025:  Marblehead sail measurement gauge -- STL files for 3D printing, to measure Marblehead leech / roach profile and various other dimensions.

May 2025:  Starting line with onshore wind illustrates one possibility for setting a reaching start line to take the fleet out to a first mark which then permits a fair beat to the windward mark.

May 2025:  Interaction, part 1 (part 2 on its way...).

April 2025:  Rules of Order for online virtual asynchronous international business meetings, assemblies, and committee work developed while chair of IOMICA and IRSA.

April 2025:  A page titled "Protesting For Dummies", being a careful explanation of what actually happens in a protest hearing.

March 2025:  A page on the Three-way Anova now completes the "Psycho Stats & Interaction" series (for now).

March 2025:  Some pages in Other Topics illustrating the construction and use of a flotation tank and dry measurement jig for 6M boats with 3D printed equipment where possible, starting with 6M tank and jig construction, establishing 6M Waterline endings in the tank, 6M boat in dry jig preliminary measurements, Stern station measurements, and Bow and girth station measurements.

March 2025:  Some sailing events seem to have increasingly bad-tempered bickering over incidents on the water.  I thought a short 2-minute welcome from the Chair of the Protest Committee might help to lower the temperature.

Site content

The material is classified into the three major headings of Design, Build, and Race.  Anything not fitting that scheme goes into Other Topics (except for Links and Reports which have a place on the main navigation bar).

Other Topics include pages on International RC racing, Measuring, Classes, Sailing venues, Event management, Event scoring, Observing, Ancillary equipment, Bulb calculator, Plans, References & book list, and non-sailing-related pages on Alphard camper-van picnic units, Photography, Duplo train track layouts, Statistical analysis of data using analysis of variance, and biographical recollections.

Scans of some International Radio Controlled Model Yacht Championship programmes and results are in Gosport 1975 (plus an article on Radio sailing history by Norman Hatfield), Durban 1978, Ottawa 1980, Dunkerque 1982, Ullnasjon 1983, Gothenburg 1987, and Berlin 1988.

Articles originally published in the American Model Yachting Association's (AMYA) excellent "Model Yachting" magazine are now reproduced on the site by permission of the Editor.

Stiffness (AMYA MY #173) (Fall 2013)
Trim & Drag (AMYA MY #174) (Winter 2013) *
Bulb cant (AMYA MY #175) (Spring 2014) *
Canoe body yaw (AMYA MY #176) (Summer 2014) *
IOM History (AMYA MY #177) (Fall 2014)
Sheeting (AMYA MY #177) (Fall 2014) *
Lift to drag (AMYA MY #178) (Winter 2014)
Velocity made good (AMYA MY #180) (Summer 2015)
VMG & pointing (AMYA MY #181) (Fall 2015)
Weather helm (AMYA MY #182) (Winter 2015) *
Wetted surface area (AMYA MY #183) (Spring 2016) *
IOM bulb drag (AMYA MY #184) (Summer 2016) *
Boundary layer (AMYA MY #185) (Fall 2016) *
Balance, part I (AMYA MY #187) (Spring 2017)
Balance, part II (AMYA MY #188) (Summer 2017) *
3D printed sail box fittings (AMYA MY #195) (Spring 2019)
3D printed spreader (AMYA MY #199) (Spring 2020)
Kinked kicking strap (AMYA MY #208) (Spring 2022)
Scale models (AMYA MY #208) (Spring 2022)
Adjustable spreaders (AMYA MY #210) (Winter 2022)
2D flow simulation (AMYA MY #212) (Summer 2023)

* Article reports data from wind tunnel, towing tank, or other experimental setting

Commercial stuff

I previously manufactured an adjustable spreader.

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2025-05-21

©2025 Lester Gilbert