Depending upon the number of entries in each sub-section the organisers retain the right to combine sub-sections during qualifying heats and finals.
No more than 2,4 or 8 (depending on the category entered) standard Plugging into the Sun® flexible solar cells are allowed on each boat. The number of PV cells on a boat may be altered during the challenge to allow a boat to compete in more than one category. The solar cells must not be modified in any way, for example by cutting away edges to reduce weight.
The age groups defining category sub-sections apply to the eldest member of a boat team. Entries in the younger classes should be from students who have received limited direct assistance from adults. Adults are encouraged to assist the students to think through problems, identify solutions, and to experiment with different arrangements for the boats and propulsion components.