The Z H T A Challenge Proposed Technical Specifications and Rules for the First Zero-Handed Transatlantic Race Draft no. 1, Jan 5,1988 1) Maximum weight: The total weight of the model and all on-board equipment and supplies, including water ballast if used, shall never exceed 500 kilograms. 2) Telemetry and Communications: All telemetry and communications with the model shall be within specified radio frequency bands, except that the model may receive navigational radio transmissions that are available to all competitors. 3) Real-Time Control: Real-time remote control of the model shall only be permitted when the model is within a specified distance of the start or finish line. This real-time control shall be limited to steering only. 4) Means of Propulsion: The model shall be propelled only by the natural action of the wind on the sails or other passive aerodynamic device, and by the natural action of the water on the hull or other passive hydrodynamic device. 5) Electrical Power Generation: Electrical power shall be generated only by on-board devices that do not consume fossil fuel. 6) Collision Damage Control: The forwardmost cubic meter of hull volume shall be constructed entirely of polyeurethane or polystyrene foam having a density not to exceed 10 kg/cubic meter. A non-structural hard surface finish of specified thickness and material may be used over the foam. Each hull of a multihull model shall meet this requirement.