A quick rule of thumb if I remember correctly is to take the distance they
have traveled in 3 minutes and drop two zeros and that is the ship speed.
For instance if the ship travels 1000 yards in three minutes they are going
10 Kts. On the radar you really need to do something when the contact has a
steady bearing and decreasing range. You are on a collision course,
regardless of how it looks to your eye.

Scott
"Karl Denninger" wrote in message
news:8vkWd.37539$755.36432@lakeread05...

In article ,
renewontime dot com wrote:


Fascinating. I'd like to learn more - can you point me at any web
sites? I can't find anything much over 25kts.

Our site has a news section, or try
http://www.marinelink.com/main/main.asp but I did a quick search on the
net and didn't find much. Better to get a subscription to "Maritime
Reporter" and "MarineNews", in the current issues there are several
articles about "high speed" vessels.

The only ships around here that run 30+ knots are the ones that are
painted
gray and have assorted pointy things sticking out from various parts of
their
superstructure.

Oh yeah, if you approach at a closing rate which they determine to be
potentially hostile, they will use the pointy things.

That will definitely ruin your day.

When I'm offshore my radar is up and operating. That's the best
visibility
enhancer that I've got.

I can see SHIPS out 8-10nm or so (visually) on a clear day/night, and on
radar quite a bit further. Land disappears 10ish nm around here, in no
small part due to the elevation of some of the buildings (which helps)

Small boats are usually not visible to the naked eye much beyond 4nm or
so,
although I will often tag them on radar significantly before that.

All this from my flybridge.

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