Thanks everyone ...

I was at Cabala's yesterday and looked at some units before reading Phil's 
post this morning. I was wondering, cause I wasn't seeing the data that 
shows up on my charts. I didn't realize that someone would be 
irresponsible enough to market such crap to boaters. Thanks for clearing 
that up. I think I'll go ahead and mount it on the bulkhead by my other 
instruments. I was thinking that swing-out mount sounded like a good idea, 
and then I thought about how most of the time I'm doing DR anyway, and 
really want the thing when visibility goes down, which probably also means 
I have the companionway closed.

Anyway, thanks, all, for the responses. Appreciate your input. 

Merry Christmas,
Tom






"Phil Agur" <[EMAIL PROTECTED]> 
Sent by: [email protected]
12/14/2007 03:56 PM
Please respond to
[email protected]


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Subject
RE: catalina27-talk: GPS






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    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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