Bill, We have a RL70CRC with an HSB to a Raychart 520. Curious about software upgrades (how does that occur) and your comment in another reply regarding tide software. Will have to try your suggestions regarding our speed transducer. We get a lot of growth on the boat here in the San Francisco Bay. The transducer seldom produces a reliable speed (or any speed) unless we clean it just prior to sailing and then sometimes it still does not work. We think this is because of growth on the bottom of the boat near the transducer. I really appreciate this forum. Achieving full utilization of our electronics takes some study and practice. Having someone here to bounce questions off is very useful. Dan Jonas (S/V Feije)