I've got a small Ritchie on one kayak, a dozen years old, and an Aqua Meter Sailor II on the other that's 23 years old, and they both work just fine. The key, though, is to adjust the compasses so that they read as accurately as possible. I carefully laid out a magnetic north-south line on my driveway with a good Silva orienteering compass; then, with each kayak on a cart so I could move them easily about, I went through the adjustment drill that's outlined on any compass's instruction sheet to ensure that the readings were as precise as possible at all orientations of the kayak. So far, neither of the compasses have let me down, nor do they show any signs of wearing out.