Related to the setting of way points, I have observed a trend for routes to converge based on each vessel using similar GPS routing software.
In the past a skipper could plot a course and expect to wander a bit prior to sighting a nav aid or landmark. Today the destination waypoint (be it a few miles or hundreds) is being set on a chart plotter or GPS with cross track error being corrected often. This practice leads to vessels following very similar routes to very similar waypoints. In my opinion this trend lends itself to a greater chance of what I call a "radar/GPS assisted collision". When inshore racing it is expected the fleet will converge on a turning or geographical point. The racing fleet has common expectations of how to approach crowded mark roundings or handle close crossings. When cruising or on a delivery, especially short-handed, variables in seamanship and skills make close quarters maneuvers much more entertaining. The result is I often use the same waypoint setting routing Dennis mentioned, having a waypoint in safe water a short distance off the intended arrival point allowing room to maneuver as actual conditions and traffic dictate. Martin Calypso 1971 C&C 43 Seattle From: CnC-List [mailto:cnc-list-boun...@cnc-list.com] On Behalf Of Dennis C. Sent: Wednesday, January 15, 2014 1:44 PM To: Cn Clist Subject: Stus-List Setting GPS Waypoints (long) I made a transit with a learning sailor who had just bought a new handheld GPS. It was a lower priced model with a map but not a true chartplotter. He wanted to see The Rigolets, the outlet of Lake Pontchartrain, so he wouldn't be intimidated should he ever do it himself. As we made turn after turn along the route, I noticed he wasn't setting any waypoints in his GPS. I mentioned it and he said he didn't need to because all the marks were in the pre-loaded database in the GPS. I suggested to him that it might be a good idea to have waypoints set in the middle of the channels where he wanted to turn rather than using the fixed marks that lined the channel. He thought about it and then the light came on. On another occasion, I helped a friend bring his new boat home from across the lake. It had a nice Raymarine charplotter. Imagine his amazement when, as we motored down the middle of Mandeville Harbor, the symbol for the boat on his chartplotter went through the middle of the seawall on our port side. What if the visibility had been zero and we were totally relying on the chartplotter? I have a waypoint set a hundred yards or so off the entrance. I can arrive at the mark then feel my way into the harbor entrance in low visibility once I have visual contact with the lights or seawalls. I have two fixed mount GPS's and 1 handheld (kept in a waterproof pouch with the batteries removed). The fixed mounted GPS's are at the helmstation and navstation and are routed through a switch so that one or the other is interfaced with the instruments and autosteerer. Anyway, relative to the subject line, ALL the waypoints in my GPS's are OBSERVED, That is, I took the boat to the spot where I wanted the waypoint and hit the "Mark" button on the GPS unit. If I'm not comfortable with it, I've been known to swing the boat around and go back and re-mark it. I always delete the other one. If I'm going somewhere new, I may enter a waypoint from a chart but once I reach that point, I may adjust it according to where I really want it when I observe the conditions at the waypoint. I'm always amazed at how many boaters use government marks, bridges, etc. for waypoints. For instance, I set a waypoint on either side of a bridge opening. I don't want to use the center of the opening. Never know when you're going to arrive in a thick fog or other adverse conditions. Government marks, buoys, bridges, etc. are things to be avoided, not to be used for waypoints. My mid-channel waypoints are set such that I am well away from points, shoals, etc. If I need more than one waypoint to navigate safely around a bend, I set them. I can always cut the corner in good visibility. So, the next time you enter a waypoint in your GPS, ask yourself "Is this REALLY where I want my boat to be in zero visibility?" Still, having waypoints you are comfortable with doesn't relieve you from maintaining a diligent watch or totally, completely trusting them. Remember, aids to navigation and navigational aids are used to help you, the boatowner, skipper, to properly navigate. I still have paper charts on board and, although I don't have a sextant, I do know how to determine my position by triangulation using a hand held compass and charted objects on the shore and waterways. The paper charts are always out for reference every time I make a long passage. Dennis C. Touche' 35-1 #83 Mandeville, LA
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