But really that's precisely what they're not allowed to do, since once they've had their 30 days in 6 months they're done. That's why the rule seems a little goofy to me. Preventing them from building more than two seems completely reasonable as a way to limit costs and keep a level playing field. How much you achieve beyond that by also limiting testing time is less clear to me. In fact you could argue that it works against the teams who have less money for design development but would benefit more from time on the water 'making the boat tick'.