hey tad, scott again. i also had to do glass work on my contender. yours is a columbia 24 according to the pics. a challenger is a flush deck model with the same hull as the 24 as the contender is also the same hull with a shorter cabin and 4 in less freeboard. my boat was in a cradle when i bought it, and i used 4 screw jack stands to lift her high enough to do work on the bottom of the keel.sure i was nervous, but i chained them together so they wouldn't kick out from her. when i was finished i lowered her back onto the cradle. those screw jacke should be available at any boat yard to rent or borrow for a few days. have everything ready to go when you get started so you can complete asap. but before you do, let her set on the jacks for a day to settle in. good luck................
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