▁r ider ▁and ▁are ▁used ▁more ▁for ▁doing ▁tr icks , ▁racing , ▁and ▁use ▁in ▁compet itions . ▁ ▁Both ▁styles ▁have ▁an ▁in board ▁engine ▁driving ▁a ▁p ump - jet ▁that ▁has ▁a ▁sc rew - sh aped ▁imp eller ▁to ▁create ▁thrust ▁for ▁prop ulsion ▁and ▁ste ering . ▁Most ▁are ▁designed ▁for ▁two ▁or ▁three ▁people , ▁though ▁four - pass enger ▁models ▁exist . ▁Many ▁of ▁today ' s ▁models ▁are ▁built ▁for ▁more ▁extended ▁use ▁and ▁have ▁the ▁fuel ▁capacity ▁to ▁make ▁long ▁cru ises , ▁in ▁some ▁cases ▁even ▁beyond ▁ 1 0 0 ▁miles ▁( 1 6 1 ▁km ). ▁ ▁Personal ▁water craft ▁are ▁often ▁referred ▁by ▁the ▁tra dem ark ed ▁brand ▁names ▁Jet ▁Ski ▁( refer ring ▁to ▁personal ▁water craft ▁manufact ured ▁by ▁K aw as aki ), ▁W ave Runner ▁( refer ring ▁to ▁personal ▁water craft ▁manufact ured ▁by ▁Yam aha ), ▁or ▁Sea - D oo ▁( refer ring ▁to ▁personal ▁water craft ▁manufact ured ▁by ▁Bomb ard ier ). ▁ ▁The ▁United ▁States ▁Coast ▁Guard ▁defines ▁a ▁personal ▁water craft , ▁amongst ▁other ▁criteria , ▁as ▁a ▁jet - drive ▁boat , ▁less ▁than ▁ 1 3 ▁feet ▁( 4   m ) ▁in ▁length , ▁in ▁order ▁to ▁exclude ▁from ▁that ▁definition ▁more ▁conventional - s ized ▁jet - bo ats . ▁There ▁is ▁a ▁wide ▁variety ▁of ▁" jet bo ats " ▁many ▁of ▁which ▁exceed ▁ 3 0 – 4 0 ▁feet ▁(