{Stus-List} Chart plotters

Steve Thomas sthoma20 at sympatico.ca
Wed Jul 21 09:32:04 EDT 2010

   I spent a week off of the west coast of Vancouver Island in June of this
year. The boat was equipped with a number of electronic aids to navigation,
including radar, but what we found most useful was openCPN, using Cmap
vector charts and an AIS receiver. AIS also works well with Seaclear, but
you are limited to raster charts. The value of an investment in a simple AIS
receiver is difficult to overstate in the heavy commercial traffic and often
reduced visibility of the west coast. We maintained a continuous watch and
checked for AIS (and radar in reduced vis.) traffic at frequent intervals.
Only at night with completely clear visibility did we reliably make visual
contact with traffic first. In all other conditions the AIS was first. The
radar had a useful range of about 6 miles.
   In one instance about 50 miles NW of Ucluelet, with reduced visibility
that I had estimated at 2 miles, an AIS target showed up on a collision
course. I do not recall the range when it was first detected, but 15 or 20
miles was about par. Anyway it was long before it showed up on the radar,
and the radar takes longer to establish what course the target is on once
you do see it. The target turned out to be a container ship, and after we
raised them on the radio and explained the situation, both of us altered
course. They gave us no reason to suspect that they had detected our
presence prior to our radio call.
   By the time the ship appeared out of the haze, it was 1.2 miles distant.
It really looked big. Their speed was over 20 knots. Nuff said.

   An AIS receiver can be had for about $400, and they are getting cheaper.

Steve Thomas
Port Stanley, ON

-----Original Message-----
From: cnc-list-bounces at cnc-list.com [mailto:cnc-list-bounces at cnc-list.com]On
Behalf Of ross and bev
Sent: Wednesday, July 21, 2010 3:15 AM
To: list cnc
Subject: {Stus-List} Chart plotters

Within a month my boat will be sailing the water around the islands off
Vancouver Island .

I'm beginning to shop for a chart plotter and wonder what the list would
recommend .

Ross MacLennan
C&C 24, Tobermory
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