Some thoughts on Instruments

Every now and then I like to make some comments about boat life for people reading this and looking for insight.

An adage that pilots learn is to trust your instruments. GPS may be off a few feet which in a narrow channel could be problematic but you can supplement with visual observation but at night offshore or in open water stress can be relieved with intelligent use of instruments.

Two absolutely indispensable aids to navigation in limited visibility is of course radar but also AIS. AIS is the Alternative Information System. While not every boat is on it, most offshore vessels are and that's where it is invaluable. On every one of our passages we tracked vessels miles away from us and followed them until we were clear. Coming up the Bay recently we talked to at least a half-dozen vessels either checking us out or we contacted to confirm their plans.

On a daily basis we hear radio calls to "vessel passing red 46" or whatever the local identifier. It is so much easier to call the vessel by name. Many times we came up behind a vessel not on AIS and no name visible that there is no alternative but to try to identify them.

At night especially I trust our instruments and watch our chartplotter for radar blips and especially AIS vessels approaching. Some boats have AIS receiving units but other vessels have no idea who they are.

Beyond AIS there is other information that is helpful. The knotmeter that can tell you the speed of favorable or opposing current. Gauges that can give you water temperature and of course depth all help pinpoint your location.

We also use radar to show us showers and squalls. It can help identify where they are and which way they are moving. On our recent offshore passage we watched a large squall on radar off to our east which was moving slightly southeast away from us and other cells moved behind us and gave us advance warning of rain and also potential wind gusts so on at least one occasion I pulled in our sails to avoid being rolled by gusty winds.

In the Army we used to talk about "situational awareness".   Being on watch is all about situational awareness. During the day visual may be good enough but in all conditions of restricted visibility know and trust your instruments.  They see more than you.