Originally Posted by codprawn
FLIR can be of use in fog - I would say that a FLIR set would be of far more use far more of the time than RADAR would on a small boat!!!
Codders, radar gives you much more information than seeing. You can view the positions of vessels relative to your own boat and relative to each other. You can see their distances from yourself and others and you can see their direction of travel with certainty. You can predict the likely movement of traffic based on its current movement and so plot you own course more effectively. Seeing comes a poor second. I've said it before but I'm going to repeat it; I've frequently seen vessels, during daylight, on the radar before I've noticed them visually.
If you're in an area when you are viewing discontinuous land, either islands or promontories, because of your low viewing angle it is impossible to discern with certainty the layout and the distances off, radar shows this clearly.
At night it can be very difficult, and sometimes impossible, to see navigation lights and the other displayed lights on vessels either because of the background illumination or simply because of your distance from them. Radar allows you to see them and make an educated guess at their likely movements. For example, if you notice a vessel following a curved path it is possible it's fishing and you may wish to give it searoom in a particular direction. Even if it isn't fishing, you're alerted to it being unpredictable and you'll be giving it that extra room.
I've no idea whether the devices you are advocating are able to discern colour, if not then you're not going to have much more information about vessels other than simply knowing they are there and that's only if you have spotted them in the first instance. If you're out at night and it's only slightly busy I'd doubt you could keep track of and make proper sense of what's happening around you by simply seeing in IR.
The notion that radar is only really of use in fog is wrong.
If you have radar and learn how to use it well, as I said to BruceB, it'll become your friend.