On Mon, 12 Feb 2007 20:03:48 -0500, "CGB" wrote:

I'm about to buy my first GPS for my boat because my LORAN finally died. I
boat in coastal New England. I am inclined to get a GPS that also includes
a depth sounder/fish finder. I know next to nothing and would appreciate
any help.

The manufacturers have the full descriptions of their products on
their websites, usually including down-loadable manuals and "what's in
the box" lists. These websites, or your local dealer, should give
more reliable information than you'll get from the random
recollections of newsgroup inhabitants.


1. Best brand? Garmin, I know is common. I saw a Lowrance (model
LCX-28C-HD) that looked very nice at the boat show.

"What's Best" questions can start religious wars! (However, I prefer
Garmin, because that's what I started with.)

2. Do I understand that when you buy a GPS it doesn't come with the charts
built in? That's an extra cost? I see some advertised as
"GPS/chartplotters." Is there a difference between a GPS unit and a GPS
unit with "chartplotter?" Without the charts, what does it do for you, just
give lat/long? How much extra to get the charts, typically.

A basic GPS receiver will give you position, speed and direction of
travel, and will be able to store waypoints, and give you bearing and
distance to them, and cross-track error while navigating to a waypoint
- in short, a basic (non-charting) receiver will do everything a
chartplotter will do, except actually plot your position on a real
chart. Most of the basic receivers do have a simple plot screen which
will show your track and position relative to your stored waypoints.

When I bought my Garmin 168 GPSMap/Sounder, charts were optional at
extra cost, but I think some models now include at least some charts
with the unit. Even if a plotter doesn't include detail charts of the
area you are interested in, it will probably have a "base map" that
will at least allow you to identify your position relative to the
larger islands - it won't be adequate for any real navigation.

3. If I have to buy charts, what brand do you recommend? How do I get
updates to them, via web, CD, flash memory, etc. Is this necessary (charts
do change). And, is this yet an additional charge?

In general, you have to but charts from the maker of your chartplotter
- Lowrance charts can't be installed in a Garmin chartplotter, for
example.

4. Depth/fish sounder needs a transducer. This is an additional charge??!!!
I would prefer a thru-hull but if I'm reading things right, these are
expensive, like a couple hundred $. Are transom mounts OK? I'd like
fishfinding, water temp., and depth.

5. Internal vs. external antennae. I think some of the models I looked at
even charge extra for the antenna and bracket!! Mine will go on a flybridge
covered only by a cloth canvas top with minimal stainless steel support
work. Would an internal antennae be OK? (lady at West Marine told me it
was "line-of-sight" and the canvas top would prohibit reception through it
because you can't see through the top!!! That's gotta be incredibly stupid,
doesn't it?)

I would expect that a unit that requires an external antenna would
include an antenna in the base price. Likewise a unit that includes
depth sounder capability should include some sort of depth/speed
transducer - probably transom-mount, with through-hull transducers
available at extra cost - again, see the maker's website, or a dealer,
for accurate information.

An internal antenna should be fine on the flybridge, even with a
canvas top, but I would recommend an external antenna if the receiver
is mounted in the cabin.

As long as I'm spending the money for this, is there a model
as described that would also serve in my auto, using a plug to the cigarette
lighter? Or, am I engaging in wishful thinking? But, I do spend far more
time in the car than I do on the boat here in New England.

You'd want to check on the availability of road maps, as opposed to
nautical charts, for that application. There are many GPS receivers
that are designed specifically for road navigation - they may omit
some features (particularly cross-track error displays) that are
useful in marine application, but include things like "lock-to-road",
and audible or visual warning of impending turns, intersections or
highway exits, which may be great on land, but are no use on the water
(and won't be available in the marine units).

6. In other words, I'm rather lost and would appreciate any help. I've
seen a lot of GPS units advertised for $500-$700 and thought I'd likely have
to spend in that neighborhood. Now thinking that I may have to buy the
bracket, the antenna, the transducer, etc. etc., all extra, it's getting to
look like maybe I ought to just get my LORAN fixed or get a new compass and
parallel rules and use them with my $12 digital watch. (for you youngsters,
that's called dead reckoning).

Thanks, in advance, for any help.

Chet


--
Peter Bennett, VE7CEI
peterbb4 (at) interchange.ubc.ca
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