OK time for me to weigh in I have no GPS and the last nav aid I owned
was loran C. I believe that GPS is a great option and an asset for
most but if you do not know DR you can and most likely will get into
trouble. As nice of an aid as they are nothing can replace good old
seamanship! I only say this since we do have a few new sailors on this
talkring and would like to see what they can add in the future so by
all means get a GPS but also know dead reckoning it could save you
allot of headaches or worse Phil is correct that some companies will
use maps instead of charts witch is not that big of a deal on the S.F
Bay but should you get close to the east side there are alot of shoals
and shallows not to mention old piers and sunken boats. In other words
you don't always get what is advertised best of luck in your hunt for
a GPS.
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From: [EMAIL PROTECTED]
To: [email protected]
Subject: RE: catalina27-talk: GPS
Date: Fri, 14 Dec 2007 13:54:52 -0800
I tend to get on a rant when it comes to GPS. They are not all
created the same and it appears the most popular are the worst
functionality wise and many models represent an actual hazard to
mariners. The GPS suppliers get a little cagey by making up
terminology regarding what they supply that they get to define
reality leaving any collisions with uncharted islands the mariners
fault.
So what do I have and where is it mounted. Mine is a Standard
Horizon CP150 (no longer available, as far as I can tell) on a
fixed mount at the wheel. The current low end is a CP180. Since it
runs in either north up or forward up modes have it fixed gets
very handy. I know it’s a tiller boat question, so I’d say the
bulkhead.
The caveat mariners ran into in the past was the source of the
charts supplied in the non-marine professional marine GPS units
was from a map database not a chart database. They determined
position with good accuracy, did waypoints fine, would leave
electronic bread crumbs, and would direct you home down the return
path. When I warned Nicky, an avid ocean small boat angler, on a
Friday afternoon about his new Garmin GPS on his new boat he
scoffed (Nicky was a younger bright engineer at Intel) but on
Tuesday he was a little more humble. Nicky tore the I/O drive out
of his new boat Saturday. He set electronic bread crumbs at high
tide on the way out as he passed over a line of rocks that would
be shoaling rocks at low tide. On the way back in the uncharted
(uncharted on his, charted on mine) rocks waited for him just
under the surface.
When I taught an intro to navigation Nicky’s plight was always
included. I also included the story of three boats that didn’t
want to hang with the main group of boats on a whale watch cruise
out of Monterey, CA. They chose to sneak off to Stillwater Cover
in Carmel, lost track of time and returned well after dark. All
three skippers were running without charts and guessing their
position by shore lights. When asked they said it was no big deal
and estimated they were a good half mile offshore.
The good news is they all three made it back the bad news is their
path took them in close proximity to a rock pinnacle that shoals a
half mile off shore at low tide. It’s like 50 feet wide at its
base and 70 tall and only about 8 feet in diameter when it breaks
the surface. It’s not on any map based GPS. Map based GPS units
besides missing all depth data only show obstructions big enough
to contain a road.
The fun one around SF Bay was to have them look for Alcatraz
Island. Not there! After some years is was added so I had them
look for Red Rocks, again not there. Actually there literally
dozens of un-mapped hazards on SF bay that are clearly charted on
the real charts.
Besides a true marine GPS having charts, some of them are using a
chart database and not just a chart image. My GPS, and I would
assume the newer Standard Horizon GPS units as well, can have an
alarm set for depth out in front of the boat. Yes while you’re
giving instructions on the next tack it is looking at its internal
chart database and based on the depth and distance you preset will
sound an alarm before you reach the obstruction.
A chart reading forward looking alarm beats the heck out a dumb
straight down depth alarm. In the case of the rock pinnacle you’d
be telling your wife to grab the ditch bag if you relied on a dumb
straight down depth alarm.
It’s also pretty important since my GPS will directly send command
to my Autohelm. The more automated things get the more you can do
but the less oversight actually goes on. Here’s automation that
checks my work even when I get tired.
Another feature on Standard Horizon GPS units is they interface
directly with your Standard Horizon DSC VHF. When you hit the
digital Mayday key on the VHF it automatically sends your ID, GPS
location, and type of emergency. Actually most any GPS with a
NEMA0183 interface can do that, but on my boat if I receive a DSC
mayday is automatically plotted on my GPS as a waypoint and
highlighted. Before I even pick up the Ram Mic to reply I can plot
a course and estimate an arrival time on scene in the GPS.
Don’t you wish the CG had just bought the right GPS and radio
combo back in the 90s instead of the system we are all still
waiting to see deployed beyond a few test zones? Wow for under a
$1000 they can receive a DSC distress signal and plot it’s
position without human intervention and head directly there.
To review GPS is good, the right one will save your life, making
it great.
1. Fixed mount trumps hand held so the display can be used
forward as up. It helps keep you oriented correctly when
fatigued in low light.
2. GPS must be chart based, showing water depth, and submerged
obstructions. How about a field of submerged dols?
3. A great GPS can use chart data to sound an alarm on depth in
your path.
4. A great GPS will plot distress calls automatically so we can
assist mariners in distress, when we are in a position to do
so.
My brother was a real Garmin fan but when he prepped his IP38 for
Mexico I made him a custom mount for a CP150 at the wheel. It was
still performing flawlessly after a year when I joined him in Cabo
for the bash up to San Diego. I used it to steer around sea mounts
coming up the coast and we logged a consistently smother passage
than the boats we were traveling with us who ran straight lines.
So yes at the wheel not down below.
Ok, but I did warn you about the rant. I’m not saying it must be
Standard Horizon, but don’t buy a unit with less features today
than the one I mounted in ten years ago. And don’t trust a
salesman; have him show you the features. It’s your boat and
you’ll be the one out there when things go wrong.
Phil Agur s/v Wing Tip
Secretary/Treasurer Call Sign WCW3485
IC27/270A MMSI 366901790
www.catalina27.org <http://www.catalina27.org/> Vessel Doc# 1039809
-----Original Message-----
From: [email protected]
[mailto:[EMAIL PROTECTED] On Behalf Of [EMAIL PROTECTED]
Sent: Friday, December 14, 2007 8:49 AM
To: [email protected]
Subject: catalina27-talk: GPS
On a tiller C27, where do you all mount your GSP chartplotter ...
or do you prefer a handheld (my family is collaborating to buy me
something useful for Christmas rather than ......... well, I'll
leave it there).
Tom
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