Radar Alarm zones/settings, Raymarine

[monte]

Hi, I've been getting friendly with my radar lately and wondering about the zone alarm settings. Last overnighter I set up an 8 mile zone all around and it worked pretty well except, once a vessel is inside the perimeter the alarm keeps going off. I then changed it to a 350 degree pie and put the other vessel in the 10 degree excluded part, but that required constant attention and was fiddly.
How do others set up their alarm zones? Can MARPA tracking be used effectively as well?
While we are on alarms, the alarm is a tiny bleep bleep coming from the plotter at the helm, hardly audible from anywhere else on board. Is there a way to connect another external alarm to a raymarine E90W, or even a way to make this one louder? I dont see any setting adjustments. It would be useless to actually alert you on passage and I want it loud enough to wake people off watch as well,.
Thanks
Monte

[JimM]

Did you get an answer, Monte? -- these are such good questions. JM

[monte]

None yet

[Talbot]

The most dangerous sector is astern - Boaters tend to concentrate on the problems ahead and looking behind needs to be done as frequently as in a car.

[jeremiason]

Unless your sleeping, an 8 mile guard zone is pretty large.

It also means you are setting your range pretty high. I normally keep my range at 3 or 6 miles and periodically range out to 24 miles to see what's out there.

I have found that when looking for small boats, like pangas, they don't appear on radar till your within 1.5 miles or less anyway.

I usually set guard zone to 2 or 3 miles and only if I am in reduced visibility like fog or no moon. Otherwise I just keep watch and monitor the radar screen every 10 minutes or so.

[chuckr]

i can only tell you what works for us

when we did the atlantic we set it at 24nm - but that does not count

on most overnight passages we set it up in 2 phases - an inner zone at about 2-3nm and an outer zone of 12-15nm - if a boat enters out outer zone we determine it's course via marpa and then try to give it a window to move through without setting off the alarm -
we run radar all night and have the radar screen up unless we are really close to the coast - we may occassionally switch over to the chart but rarely -
as for marpa -- well it is better than nothing on the course of the vessel -

we also run ais by the way

hope this helps

[sy_gilana]

We set up a torus shaped guard zone, from 2 to 4 miles, so radar clutter close by wont trigger. We leave about a 2° opening astern (at least the time to cpa is less there)
AIS and MARPA are also used religiously, as well as effective watch-keeping in accordance with COLREGS.

[monte]

thanks for the replies, sounds like we are kind of on the right track