Need some Recommendations

[Captain Smollett]

I did a search for this a while back (earlier in the summer, I think), and found numerous references Garmin GPS's using a proprietary protocol. This protocol has been largely reverse engineered, and there ARE F/OSS products using the protocol.

cf, for example: Linux Aviation How To

and the quote therein:

Unfortunately, interface software that runs under Linux is not available for many commonly available consumer GPS receivers, mostly because the early years of GPS were not particularly Linux friendly. When low cost consumer GPS units first became available, none of the manufacturers provided any documentation for their proprietary communication protocols. This ... made life difficult for those that wanted to develop their own software for these units. They had no choice but to reverse engineer the interface communication protocol using the manufacturer provided software for Microsoft Windows, serial port monitors, and lots of hard work. The first public specification for the Garmin protocol was done this way (and as you can see below, the Garmin units are pretty well supported under Linux).

Fortunately, the future looks much better for the development of open source GPS software. Many GPS manufacturers have since ... chosen to show some respect for their customers right to fair use. Many now publish the specifications for their communication protocols.

So, maybe the info I saw before was dated.  I cannot lay my hands on the specific reference now, but it seemed to suggest that one COULD get Garmins to work, but they were not really "open."  I also remember seeing on Garmin's own web site areference to their "proprietary" protocol, so even if they've opened the specs up for third party developers, their code itself may still be closed.  I'd have to research it more than I have time for right now.

Given that, as a consumer, I have a choice between 'closed' (Garmin) and 'open' (Magellan), and they both offer good, usable products of similar quality, I will choose the one more friendly to open standards.  I know the Magellan works with the software I already use (Sea Clear II and Chart Navigator).

[AdriftAtSea]

Yes, the Garmin units do have a proprietary protocol...but the GPSMap 76, 72, 60, 27x, 37x, 398, 498, and quite a few other models also can be configured to output NMEA 0183, using a standard serial cable.

[Ol' Coot]

FWIW...

GPS

My Garmin 38 handheld (over 10 years old) sends a one directional 4800 bps NMEA data feed via dedicated serial cord.  Its still in my emergency bag with fresh batteries if need to drive a connection to my PC, drop the newer one overboard,  or, God forbid, I need to ditch.

My (newer) Garmin 76 Map does the same (with different $35 wire), but has a 12 channel receiver, and WAAS capability.  Now I can tell within a boat length where I am (woohoo!).  Aside from the much quicker signal acquisition, I'm not sure of the additional value.  If I can't tell where I am within 30 feet by opening my eyes, I've probably had a bit too much grog to be on the water, and can't figure out how to turn on the GPS.

If you have software that can interpret and use the data feed (and I do believe that the NMEA feed is 4800 bps - serial) it should not matter whether you like windows, linux or mac (I'm platform in-different, if it works, RUN it!)

BTW - I think the major difference between the Garman 76 and 72, is that the 72 does NOT output a NMEA signal.

I have a Magellan FX324 MAP permanent mount unit with external rail mount antenna and dual outputs (can direct one to Otto the Auto-pilot and separate one to the computer if need be.)  Not the most sophisticated unit in the world, but purchased at about $300 1 and 1/2 yrs back at WM.  I haven't yet seen an equivalent unit under $600 so I can't complain.

PFDs

I prefer the automatic inflatables with built in harness in a critical situation.  However, I don't carry sufficient numbers to cover the max numbers of guests, and don't want to wear the inflatable on a calm day when there are multiple crew aboard (single handing is another issue.)  In order to meet CG requirements I have a couple of cat 5s aboard, and round out the necessary requirements with Stearns vest (water skiing variety with lots of webbing belts and buckles.)

[CharlieJ]

We use both a plain 76 and a 72 ( no mapping) We use the very same cable with either unit to talk to Sea Clear II on our laptop. No problems.

[LauraG]

The only difference between the Garmin 72 and 76 is screen resolution. The 76 has better resolution. Not really necessary as far as I'm concerned. I have no trouble reading the 72.

[AdriftAtSea]

Actually, I think the real major differences between the 72 series and the 76 series are battery life and screen resolution. 

As for PFDs, I use a Spinlock Deckware Pro, which is an inflatable PFD with an integrated harness.  It is the simplest harness to adjust, and the harness is based on a Petzl harness design.  Petzl is bettr known for making climbing gear.

[LauraG]

Here is a link to the Garmin website where you can compare the 72 and 76. It appears that the battery life is the same. I haven't tested them personally. The comparison does show that an external antenna can be connected to the 76 but not the 72.

http://www.garmin.com/outdoor/compare.jsp

[Ol' Coot]

We use both a plain 76 and a 72 ( no mapping) We use the very same cable with either unit to talk to Sea Clear II on our laptop. No problems.

Well, you own the 72 and you're using it so it MUST have the data feed.  My mistake.  When I was shopping a couple years ago, I couldn't find anything in the literature that said "NMEA output" so I moved up to the 76.

Looks like I coulda saved a couple bucks.

Kevin

[CapnK]

Fortis (and Tom) -

Actually, when I did the "input-line-from-jerry-can" thing, it was with a diesel engine. That said, your advice was right on, and was sorely absent from my post.

When I did that, it was after I'd consulted my diesel book to make sure it was possible, so I was aware of the fact that the fuel return was dumping into the main tank, and kept an eye on it - easy for me to do on that boat, as the 6 gal tank resided under the aft-most cockpit seat, and had a top fill.

I could see it easily doing the very thing you described. Thanks for adding that information to the discussion. Grog for you, sir. :)

[Joe Pyrat]

Don't wear an inflatable UNDER your foul weather gear!

LOL, you know, it never occurred to me to tell someone that, but from now on I most definitely will.