An alarm set to a CPA distance might be fine in the open ocean ... but
some fine tuning would make it also useful in a bay or close quarters
(when there are many other many boats within 1 nm), to alarm when the
danger is very real, rather then someone just being in my proximity

For example #1, if the software could determine if there is a real
collision potential. If a freighter is on a direct collision course
with me, and we are head on, I would want the alarm to go off at a
greater distance then if we are at right angles. It could take me
several minutes for me satisfatorylly (to my wife) get out of the way
if a freighter is coming right at me, vs at a right angle 30 seconds is

all I would need (I could just stop and wait)


For example #2, if the software could determine how rapidly another
boat and I are closing to each other, or a "time duration until
collision (TDUC) - i made this up" then it could allow another sailboat

my speed running behind me and won't catch up for 20 minutes to get
much closer then a 40mph speedboat five times as far away but will
reach me in 2 minutes. By setting TDUC = 120 seconds, it would alarm on

the speedboat. If I can easily change TDUC based on being at the helm
already, or longer when I step away from the wheel, that would be
useful ... or have two different settings for TDUC (autopilot = on or
off) that would be useful too, but I would still want to easily adjust
based on what I think my reaction time is, and how much traffic is
around me.


This is not a complete thought, I see I have to go and cannot finish
this now, if there is an interest let me know and I will ...