Dont go faster then the weakest link in the boat can hold on, or leave them at the dock. Full canopies are the safest, when wearing the appropriate 5 point harness. Canopies have to be carfeully engineered and insalled though, otherwise the seam can crack and break under pressure and rip the polycarp away and drown/crush the occupants. So dont just go buy some glass and cover your cockpit. An open boat has the same principles as a motorcycle, better to be thrown away from the accident then caught under it.