sentences:  As a result, many racing Olson 30s, in an effort to tweak performance and increase the longevity of an already very resilient boat, have had minor-to-extensive work done to maximize the performance of the boat within the class rules.Many boats have been upgraded to a Ballenger double-spreader rig, frequently using the original spar and a retrofit kit that includes new shrouds and two pairs of spreaders.This stabilizes the otherwise flexible rig.