Harken gross-trim/fine-tune mainsheet systems are easy to install and use. These optimized systems decrease overall line clutter because they use less line than traditional gross-trim/fine-tune systems. For fast trimming, pull both tails of the mainsheet. To fine-tune or to trim using a higher purchase, pull a single tail.

Two-speed mainsheet systems come in three configurations for boats from 6.5 m to 11.8 m (22 ft to 39 ft), with mains as large as 32.4 m² (350 ft²).