It doesn’t matter if you are sailing a 29er or TP52, space is precious. When it comes to optics, the last thing you really want is a  10 pound  clunker swinging back and forth below deck just waiting to give someone a concussion. That’s why we are big fans of the Barska Deep Sea Monocular ($80). It’s 7x magnification is perfect, just enough to get you a good view, but not so strong to make stabilizing your view impossible. Plus, the internal rangefinder and directional compass are a HUGE benefit when a sailor is calling a layline. All that in a 13 oz. package!