We’ve been thinking through the regulations for boat races using mini-motorboats made of concrete (mortar). The rules currently under consideration are as follows:
- The finished boat must have an outer outline that fits within the dimensions of an A4 sheet of paper
- The use of mesh or woven fibers in the boat’s structure is prohibited
- Both organic and inorganic fibers may be used, provided they account for less than 1% of the weight and are short fibers no longer than 15 mm.
- Apart from fibers, the only organic substances permitted are chemical admixtures. All other organic substances are prohibited.
- Cement, water, aggregates made of inorganic materials, admixtures, and chemical admixtures may be used. However, these must be limited to materials specified by JIS and actually used in fresh concrete.
- To enhance the excitement of the competition based on data, the weight (without suction cups) and time will be measured before and after the race
- Competitors may prepare multiple boats and switch them for each race. However, all boats must be registered and inspected in advance at the time of entry to ensure they meet the regulations.
- Submit 4–6 PowerPoint slides in advance explaining the mix design, dimensional drawings, and manufacturing process
- During the race, the boat must float in the U-shaped trough and have enough room to move freely
- If the boat sinks during the race and any part of it touches the bottom of the U-shaped trough, the competitor will be disqualified.
- The course will be a straight line with a total length of 5 m plus a 1 m buffer zone, for a total of 6 m. Since the length of the boats varies by competitor, the finish line will be set 5 m from the front of the boat.
- Only TAMIYA underwater motors are permitted, and the competition host will provide the motors and batteries.
- The motor must be attached using the suction cup included with the product. If the boat is damaged to the point where it cannot run during the installation of the suction cup before the race or during the removal of the suction cup after the race, the competitor will be disqualified.
- If a competitor is dissatisfied with their time or is disqualified, they may retake the race once using a different motor and new batteries. In this case, the faster time will be recorded.
- In the event of any other issues, a competition committee consisting of multiple members will make decisions on a case-by-case basis through consensus.
