▁at ▁least ▁ ▁from ▁do cks , ▁sw im ▁areas , ▁and ▁the ▁shore , ▁and ▁other ▁boats ▁should ▁ste er ▁clear ▁of ▁ski ers ▁by ▁at ▁least ▁. ▁Without ▁proper ▁space ▁and ▁visibility ▁ski ing ▁can ▁be ▁extremely ▁dangerous , ▁ ▁but ▁ski ers ▁should ▁wear ▁a ▁life ▁jack et ▁regardless ▁of ▁sw imming ▁ability . ▁Spe cially - des igned ▁life ▁jack ets ▁or ▁ski ▁v ests ▁allow ▁movement ▁needed ▁for ▁the ▁sport ▁while ▁still ▁providing ▁flo ation ▁for ▁a ▁down ed ▁or ▁injured ▁sk ier . ▁ ▁The ▁most ▁common ▁water ▁ski ▁inj uries ▁involve ▁the ▁lower ▁legs , ▁such ▁as ▁the ▁kne e , ▁because ▁a ▁fall ▁at ▁high ▁speed ▁can ▁create ▁irregular ▁angles ▁of ▁collision ▁between ▁the ▁sk ier ' s ▁body ▁and ▁the ▁water ▁surface . ▁Another ▁common ▁cause ▁of ▁injury ▁is ▁coll iding ▁with ▁objects ▁on ▁or ▁near ▁the ▁water , ▁like ▁do cks . ▁ ▁The ▁to w ▁boat ▁must ▁contain ▁at ▁least ▁two ▁people . ▁In ▁most ▁states , ▁the ▁observer ▁will ▁need ▁to ▁be ▁at ▁least ▁ 1 2 ▁years ▁of ▁age . ▁The ▁driver ▁maintain s ▁a ▁steady ▁course , ▁free ▁of ▁obst acles ▁to ▁the ▁sk ier . ▁The ▁observer ▁contin ually ▁obser ves ▁the ▁sk ier , ▁rel ays ▁the ▁condition ▁of ▁the ▁sk ier ▁to ▁the ▁boat ▁driver , ▁and ▁if ▁necessary , ▁ra ises ▁the ▁" sk ier ▁down " ▁warning ▁flag , ▁as ▁required , ▁when ▁a ▁sk ier ▁is ▁in ▁the ▁water , ▁returning ▁to ▁the