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GPS purchase advice needed

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Steve Blackburn
Master Marine Consultant

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Canada
1091 Posts

Initially Posted - 10/19/2007 : 22:48:14

Someone convinced me to buy a GPS.

I went to take a look at the now discontinued Garmin 492 and am very impressed! Would look great on top of my wheel. Only $465. Any alternatives I should consider? Will it link with my future auto-helm?

Marine, Automobile - Chart Plotter, Map, Tide Prediction, Trip Calculator - Antenna, Maps Software, Protective Cover, Vehicle Mounting

Garmin 520

Marine, Automobile - Chart Plotter, Display - Color, Sonar / Sounder, Trip Calculator - Display Unit, Maps Software - GPSMAP
$508

Garmin 276C

$412

Steve Blackburn, Calgary, AB
C250WB - 1999 - Hull 396

Edited by - Steve Blackburn on 10/19/2007 23:01:23

Nautiduck
Master Marine Consultant

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USA
3704 Posts

Response Posted - 10/19/2007 : 23:14:55

I have the 492 and found it really did the job on our San Juans cruise. It has all the detailed coastal US and parts of Canada. That is a good price.

That 520 looks good except I am not sure about its map. Here is what I read. "And instead of a traditional basemap, the 520 has a basemap of worldwide satellite images. It also has an SD card slot so you can add additional detailed maps without connecting to a computer."

Satellite photos are cool but you need the marine cartography data to know where the rocks are, depth, navaids, etc. Looks like you may have to buy cards to get that data. Cards are $$. That is the value of chartplotters with the built in coastal maps. Go to the Garmin site for lots of information about the basemaps and cards.

As an example - we would notice on the 492 that there was some sort of thing coming up (as indicated by a diamond shaped symbol). Put the cursor on the thing and up pops "submerged rock, covered by tide." You need that kind of data.

As far as connecting to autohelm I don't know. To be honest I tried to sell our autohelm but the Admiral stopped me.

Edited by - on

Steve Blackburn
Master Marine Consultant

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Canada
1091 Posts

Response Posted - 10/19/2007 : 23:26:52

I agree that the marine charts are much better than satelittle images. Too bad we can't get both and switch from one to the other?

Edited by - on

delliottg
Former Mainsheet C250 Tech Editor

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USA
4479 Posts

Response Posted - 10/20/2007 : 01:53:52

Steve,
We've got the 276c & love it. You can get a refurbished model from EdgeGPS for about $350 + shipping. We've had absolutely no problems with ours except a battery that Garmin is replacing on warranty. You can pick up an extra battery for less than $20 though (we did). Garmin wants $60 + shipping for the same battery, so do your homework (or ask me where to go).

One caveat, it only comes with basic maps, so expect to spend another $100+ in charts for your area, and another $200 if you want road maps. The roadmap package that comes with a 128MB chip, and DVD with maps of all of North America (US & Canada) plus a bean bag holder, 12vdc power cord & speaker was $172 + shipping. This package however, is what sold it to Rita, she originally just thought of the GPS as another of my "toys", but now wants one for herself to use in her car.

All totaled, we've spent the best part of $600 for the GPS, it might be worth looking into units that come with charts & maps built in. I haven't done the research, so I don't know what turns out to be the best deal.

I still haven't selected the best place to mount it, but I have a tiller, not a wheel, so it's not as straightforward as it might be for you.

The 276 will definitely drive your autopilot, it's one of the reasons I bought it.

You can also hook up a Garmin depthsounder & use the 276 as the display. I haven't done this and probably won't, I've got a Raymarine Bidata for depth & speed & don't see any real reason to mount another transducer, although it would be cool to have the depth displayed side by side with the chart.

If you have any questions about the GPSMap 276c feel free to drop me a line. I can also provide links to the cheapest prices I've found for the various bits & bobs I've bought for it.

Edited by - on

GaryB
Master Marine Consultant

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USA
4300 Posts

Response Posted - 10/20/2007 : 09:06:24

Look at the GPSMAP 378 (Fresh Water Charts) or the GPSMAP478 (Saltwater Charts). It does it all plus XM Satelitte Radio and Weather including Radar and Satellite. It looks just like the 276C. Also has every street in the US preprogrammed along with 5 or 6 million points of interest. Only problem is the price is around $900.00 if you shop around plus you need the XM antenna which is another $200.00 or so.

I bought the GPSMAP378 about a year ago and love it. By a twist of fate I had planned on sailing on a freshwater lake but just bought a boat on the coast so now I'll have to buy the saltwater SD card.

Oh well! At least I have a boat to sail now!

GaryB

Edited by - on

Frank Hopper
Past Commodore

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Pitcairn Island
6776 Posts

Response Posted - 10/20/2007 : 09:38:10

This guy sells factory reconditioned ones with full factory warranties. I am very happy with mine.
http://search.ebay.com/_W0QQsassZedgegpsinc

Edited by - on

KD4AO
Navigator

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USA
202 Posts

Response Posted - 10/21/2007 : 06:25:35

I have the 498, it is the same as the 492 but with a sounder. It is great unit.

Edited by - on

britinusa
Web Editor

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USA
5404 Posts

Response Posted - 10/21/2007 : 07:29:15

It's only because we absolutlly love our Garmin 192C that I don't throwup seeing the low prices quoted in this thread.

The 192 comes with the entire USA and bahama islands charts. The features are outstanding, the Admiral would not leave the slip without it (see my previous thread about gps for the new car.)

The good news is that if the 192 did fail, then these new beauties would be at a much better price. (We paid over $1,000 for the 192C in 2005, but then we did buy it from West Marine.)

Paul

Edited by - on

Nautiduck
Master Marine Consultant

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USA
3704 Posts

Response Posted - 10/21/2007 : 19:10:39

Paul, don't feel too bad. The prices have dropped pretty dramatically in the past two years. You were an "early adapter" and those folks who pave the way always pay more. Also, please google any product you want before going to WM. I love WM (ask the Admiral) but they can be pricey, especially on high-end stuff.

If you do throw up, make sure to lean over the rail....

Edited by - on

Champipple
Master Marine Consultant

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USA
6855 Posts

Response Posted - 10/21/2007 : 19:38:27

Before you buy the top of the line how are you going to use it?

Are you planning on roaming around the continent where you will need a bunch of different maps or are you going to stay in one area.

Do you want to cut a hole in the bulkhead, wrench somehting onto the binnacle or put it on a swing arm out of the cockpit...

Are you attaching it to a laptop in the cabin or keeping it in your pocket only checking it occasionally.

Personally, I get by fine without the expensive models. The only time I actually had one with full mapping capability I ran aground...In an area I knew we wouldn't have depth...

Answer a few of those questions and it should lead you to a model. The few you have listed are almost all identical - with the exception of the pixel quality your not getting very much different functionality. The 508 price looks mighty tasty though...

Edited by - on

Dave Bristle
Master Marine Consultant

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Djibouti
10005 Posts

Response Posted - 10/22/2007 : 11:21:52

Be sure to check out http://www.gpsdiscount.com/

I found them to be good to work with, and prices are pretty competitive.

Edited by - on

Steve Blackburn
Master Marine Consultant

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Canada
1091 Posts

Response Posted - 10/22/2007 : 13:32:29

I noticed that you have tide data in there. I understand the data is shown in a single graph type. However should I also assume that the GPS map contours/depths are adjusted according to tides at any given time?

Do you know if the 276C has the same preloaded marine charts as the 492 does, or do I have to cash out more for these?

Edited by - on

Nautiduck
Master Marine Consultant

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USA
3704 Posts

Response Posted - 10/22/2007 : 14:36:54

<blockquote id="quote">quote:<hr height="1" noshade id="quote">I noticed that you have tide data in there. I understand the data is shown in a single graph type. However should I also assume that the GPS map contours/depths are adjusted according to tides at any given time?
<hr height="1" noshade id="quote"></blockquote id="quote">

No, the maps on the chartplotter show the same information as the official navigation charts. Depths are at mean low tide.

Edited by - on

dlucier
Master Marine Consultant

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Virgin Islands (United Kingdom)
7583 Posts

Response Posted - 10/22/2007 : 14:38:28

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by Champipple
 Personally, I get by fine without the expensive models.<hr height="1" noshade id="quote"></blockquote id="quote">

My handheld GPS only came out of the microwave twice this past season, once to ensure the batteries were good and another time when I was just playing around. That's why I'm not in a hurry for a chartplotter.

Edited by - on

welshoff
Captain

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USA
253 Posts

Response Posted - 10/22/2007 : 15:21:15

I went with the Garmin 420s. I haven't added the sounder yet (sonar), but can when needed. The 4" color screen works great and it fits nicely on a Ram mount between the Edison wheel guard. I can easily rotate it forward when sitting forward of the wheel or rotate it back when sitting behind the wheel.

This unit works great in the Puget Sound. Has marine maps including tide stations (graph and table format), and marina information.

Also, has SD card slot, internal or external antenna (depending where you mount it). I think a lot of functions for medium level pricing. For my use I couldn't justify price wise to go with the 520 model just to get a 1" larger screen. West Marine made me a deal for around 4 boat units w/out the sounder July '07.

Edited by - welshoff on 10/22/2007 15:30:30

delliottg
Former Mainsheet C250 Tech Editor

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USA
4479 Posts

Response Posted - 10/22/2007 : 15:38:43

Steve,
The 276 has only a basic map included for both marine & on the road use. You will need to get a chart chip for the area you're planning on using it in, and road maps if you're planning to use it on the road. These cost us about another $300 over the original price of the unit. The overall cost seems to work out about the same, and my impression is that there's more versatility with the 276, but this may well be bias on my part as I really like the unit. In fact, I'm buying a second one for Rita to use in her car.

Chart depths are usually measured from MLLW (mean lower low water), which is the average of the lower low tides over a roughly 19 year period. See entry on [url="http://aa.usno.navy.mil/faq/docs/calendars.php"]intercalation [/url]if you're interested in why they're averaged over 19 years. Individual tides can be lower than the MLLW datum, which is how you can get minus tides. You'd simply add the minus tides (EG you've subtracted) to get the actual level. Other things can affect tides as well, such as atmospheric pressure, high winds, etc. Your GPS will only show charted depths, just like your paper charts. They are not adjusted for tide.

Charted heights are usually measured from MHW (mean high water). So, when you're figuring bridge clearances the charted height given is the height above MHW, instead of MLLW.

Edited by - on

Nautiduck
Master Marine Consultant

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USA
3704 Posts

Response Posted - 10/22/2007 : 16:28:30

Don, it all depends where you sail. In many wide open areas a chartplotter would seem superfluous. In the San Juans, where Steve is planning to go, there are numerous rocks and other obstructions that you do not want to hit. Without a chartplotter a sailor would have to keep constant bearings on a paper chart. A chartplotter mounted on the pedestal gives you that information on an ongoing basis and shows you exactly where you are. The chartplotter is not there to help you determine what direction to go, heck the islands are all within sight of one another. The chartplotter gives you access to important data about your immediate vicinity, including where the rocks are. Did I mention rocks? There are no sand bars in the San Juans, only rocks. These are the tops of mountains that did not get high enough to become islands. SOme of them came just a few feet short.

If you hit one you are in big trouble. A chartplotter is a modern tool that is a great fit for certain sailing locations and this is one.

Now Steve don't get worried that a sail in the San Juans is constant dodging of rocks.

The rocks and wrecks are well documented and very few people hit them. They are easy to avoid. My point is that a chartplotter, with a detailed basemap, is a great tool in the San Juans. We had ours on every minute we were away from the dock and I wouldn't do the trip without one.

Edited by - on

Steve Blackburn
Master Marine Consultant

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Canada
1091 Posts

Response Posted - 10/22/2007 : 17:02:34

Very interesting. Too bad there isn't a type of a wheel button that will let you go forwards and backwards in time and let you see the chart being adjusted depthwise. Go to a spot where you want to launch your achnor and "play" the tides 24 hours in advance making sure you're going to have enough depth on your whole swing radius.

Could fix your draft depth, and obstacles showing in RED would the the ones you hit, green is ok (you can run over them at this time).

Maybe I just invented something here? Sorry I'm a programmer and computer consultant, we tend to think of these things.

Edited by - on

delliottg
Former Mainsheet C250 Tech Editor

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USA
4479 Posts

Response Posted - 10/22/2007 : 17:20:18

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Could fix your draft depth, and obstacles showing in RED would the the ones you hit, green is ok (you can run over them at this time).

Maybe I just invented something here? Sorry I'm a programmer and computer consultant, we tend to think of these things.<hr height="1" noshade id="quote"></blockquote id="quote">

Actually they already make this, it's called charting software, it's just generally not available on small chart plotters like we've been talking about. However the idea of adjusting for tides is pretty cool, don't know if I've seen that. Seems like a large liability issue if someone whacked their keel after trusting the software. If instead you use a laptop, tablet PC, or large chartplotter capable of displaying the program, you can do exactly what you're talking about. Even Pocket PCs can do it. It's just that none of them with the exception of maybe a Panasonic ToughBook are able to stand the environment.

Edited by - delliottg on 10/22/2007 17:22:50

barleyrooty
1st Mate

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64 Posts

Response Posted - 10/22/2007 : 17:34:49

Very happy with my 276C here. I shopped around for the chip and map data, and got them both together for around $150. You have to pay around another $100 if you need a new "area". I got a cover too which seemed like a smart move.

I had the same thought that it should adjust the depth markers using it's tide data. Would be great if it had a continuous display of estimated depth too, as a backup to your depthfinder.

Edited by - on

Steve Blackburn
Master Marine Consultant

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Canada
1091 Posts

Response Posted - 10/22/2007 : 17:36:46

Right, that's a good way to put it. GPS depth should = sonar depth all the time. I understand wave height comes into play, but still...

Edited by - on

Dave Bristle
Master Marine Consultant

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Djibouti
10005 Posts

Response Posted - 10/22/2007 : 19:25:42

As mentioned above, wind and atmospheric pressure also affect depths in ways that tide tables can't predict, and the effects can be substantial in areas with large tide swings, and even on the Great Lakes where there are no tides.

Edited by - on

Dave Bristle
Master Marine Consultant

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Djibouti
10005 Posts

Response Posted - 10/22/2007 : 20:57:48

I've been looking into this a little--might be in the market for a larger screen for the boat... From what I see, the Garmin 420, 420, and 525 don't appear to have useful built-in charts. They have "satellite-enhanced base maps" which appear totally inferior to Blue Charts--possibly useful for hikers or something... They might be better than Garmin's older base-maps, but those were completely useless. Whether they're built in or add-ons, be sure you're getting charts--not base-maps. And I will be looking for an SD card slot--not Garmin's proprietary data card. That way I can load up the card in a slot on my laptop instead of via an umbilical cord.

Edited by - on

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