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Electronics Review

The Garmin 178C provides accurate navigation and a detailed fishfinder all in one

Date: 9/6/04
Tackle type: Electronics
Manufacturer: Garmin
Reviewer: JIP

Total Score: 8.5

Introduction: Last season Garmin announced a brand new color combination unit that consists of a GPS and fishfinder. Now the much anticipated Garmin 178C units are currently shipping and we got our hands on one to give you the scoop on this exciting contemporary gadget.

Garmin GPSMAP 178C Sounder Specifications

Case Plastic Alloy
Unit Dimensions 6.3" x 4.9" x 3.7" (W x H x D)
Weight Internal Antenna: 23.9 oz, External Antenna: 23.6 oz
Display Type 256-Color CSTN
Display Viewing Area 3.2" W x 3.2" H (4.5" diagonal)
Display Resolution 320 x 320 pixels
Backlight Adjustable CCFL
Processor 200MHz
Transducer Frequencies 200kHz Single, 50/200kHz Dual
Transmit Power (Dual-frequency transducer) 500Watts (RMS) 4000Watts (PTP) output
Transmit Power (Single-frequency transducer) 400Watts (RMS) 3200Watts (PTP) output
Receiver 12 parallel channel
Waypoints/icons 3000 waypoints, 10 nearest, 10 proximity
Routers 50 reversible routes with up to 50 points each, plus MOB and TracBack® modes
Antenna Internal/External available
Alarms Anchor drag, arrival, off-course, proximity waypoint, and clock
Maps Basemap, uploadable maps
Power source 12V DC, 1.2 Amperes (10-35 V range)
Warranty 1 year
MSRP $921.41 (internal antenna with single-frequency transducer)
$942.84 (internal antenna with dual-frequency transducer)
$942.84 (external antenna with single-frequency transducer)
$964.27 (external antenna with dual-frequency transducer)


Impressions: Advanced electronics are becoming more of a necessity than a luxury item to have on today's boats. The Garmin GPSMAP 178C Sounder is a combination unit consisting of both a GPS chartplotter and a sonar fishfinder sporting a high resolution color display that's all packaged into a decent sized chassis of 6.3" x 4.9" x 3.7" (W x H x D).  The plastic casing on the 178C is grey and comes with a black colored swivel base mount. The overall design layout of the display and buttons all match up nicely. The internal antenna model has a little fixed stub that sticks out on the upper right that won't get in the way and looks quite solid. This unit comes with configurations that give users an option on having features such as an internal or external antenna and single or dual-frequency transducer. The unit is feature packed with many useful features that all anglers should familiarize themselves with to improve fish finding abilities and ultimately benefit your catch ratios.


Introducing the new Garmin 178C that has both GPS and Sounder in one compact size

Real World Tests:
We chose to put this colored Garmin unit on our Boston Whaler where it will be tested to the fullest on the ocean where the GPS will aid in navigation inshore and offshore, giving the sonar unit the opportunity to read the depths of the ocean, allowing us to check the visibility of the new display in bright sunlight, and assess the unit's durability in harsh offshore environments.


Installation: Installing the 178C is simple and quick.  Run the transducer wire, find the optimum position to mount the transducer as specified by the instructions included with your  unit, then drill and secure with screws. On the console end, you'll have to make the decision on a flush mount or using the swivel base, which is a nice feature to have with the Garmin. We chose to use the swivel base and it mounted speedily. Mark and drill the proper sized holes and then figure out where you want to drill the hole to run the wires through the console, and completing it by using a clam shell or similar type of product and fill the hole with silicone to prevent any water from entering the compartment below. Hook up the fused power cables and you're finished.


Installed on top of the console, the Garmin can be rotated via its swivel mount


GPS Performance: Garmin has been designing GPS receivers since 1989 and is considered a leader in this technology. Garmin receivers have 12 parallel channels with continuous tracking and uses up to 12 satellites to calculate and update your current position, and is WAAS enabled. WAAS stands for Wide Area Augmentation System which in simple terms are a set of satellites and ground stations that provide GPS signal corrections by complex algorithms. So for anglers, this means that you'll have even greater accuracy in pinpointing those sweet fishing holes. With the combination unit, we were able to test the GPS on the water, looking at the GPS+BlueChart and fishfinder to match up the structure.  Results were very accurate, especially when looking for those vital rock structures when ferreting for rock fish.


Acquisition Times, Cold: approx. 45 seconds, Warm: approx. 15 seconds


Another important feature on any GPS should be fast acquisition and update rates. When I move about on the water, I want instant updates of my position to show me which direction I'm headed as the boat is turned. The Garmin 178C receiver is specified to have an update rate of 1 per second (continuous) and does a great job as I make turns or while I'm running at all speeds. Straight out of the box, the initial acquisition time takes some time when using the AutoLocate mode, but Garmin suggests the graphic initialization method to speed up the process. I recommend that you do this from home or at your boat berth well in advance of your first trip. Any time after the initial acquisition we found that the receiver locked onto satellites quickly, meeting our satisfaction in terms of prompt acquisition.


Sounder Performance: The 178C test unit has a dual-frequency transom mount transducer capable of 200 or 50KHz. At an operating frequency of 200KHz its beamwidth is at 15 degrees and 50KHz with 45 degrees. Having this dual-frequency sonar capability on the Garmin combo unit displayed great coverage at the low frequency while still being able to acquire high bottom resolution in combination with the 200KHz sounder. This allowed us to see the bottom structure to accurately target those rockfish in prime fish holding structure. The maximum depth the sounder is capable of is 1500 feet below. We were able to easily test this at Monterey Bay where the bottom is actually a huge canyon dropping to depths of well over 2000 ft. While trolling for salmon we were able to keep an eye on the depth without any problems above the 1000 ft mark, and noticed it started fading only when it reached 1500 mark.


The denser the object, the darker color return.  Without the Whiteline turned on, the bottom shows up in red (Disregard the vertical lines, that's due to the different in our camera and LCD speeds)


In addition the sounder ran through various performance tests while on the go. Through various speeds, we kept an eye on the sonar's capabilities on detecting large fish, bait-balls, and bottom structure.  The results were good running at low to higher speeds while searching for fish. Coupled with a detailed wide coverage area, the depth sounder also features many display options that make the Garmin an even more powerful unit that we'll cover in the feature section below.


Display: Like other hi-tech electronics, the display is one of the components we've seen a dramatic change in over the years. The Garmin combo unit uses a 3.2" X 3.2" 256-color CSTN display that outputs 320 X 320 pixels in resolution. Being compact, it has its pros and cons. The small unit fits nicely on smaller boat consoles such as bass boats, but can be a bit small for larger boats. The display also gives you the capability to adjust the backlighting to accommodate the surrounding lighting for sunny and low light days. The high resolution display does fine with the fast 200MHz processor that powers the Garmin 178C. When in motion or scrolling using the cursor, the refresh rate is excellent with zero screen blanking.


A little more on the newer and more advanced CSTN(Color Super-Twist Nematic) display. This is an LCD that is based on a passive matrix, which is less expensive. In the older technology, these displays have an extremely slow response time and suffer from ghosting. With this new CSTN display it's much faster and has great resolution that rivals the TFT type of displays such as the one on the Garmin 188C.


The LCD is high resolution and sharp and can be adjusted


How does the 178C CSTN display perform while fishing on the water?  On dark to low light periods the display is amazing. The display is easy to read and the quality is exceptional, especially the detailed color BlueChart symbols, density of underwater objects detected, etc. The display readability in direct sunlight is very similar to the TFT displays.  The view is clear, bright, and has nominal glare when looking at the screen straight on.


Pages: The pages on GPS and depthfinder units are just as important as the performance of the GPS receiver and sounder. Being able to view critical data is what users are really looking for. If you're familiar with the Garmin 188C or similar units, the 178C has an improvement when it comes to the pages. A combination unit has the ability to show a split screen of GPS navigation and sonar page, and getting to that page quickly is a big plus.  With the 178C it is just a push of a button. The old format for Garmin used to be Map, Sonar, ... and to reach the split screen, it required much more button pushing. Now when you press the page button, you will first see the Map, then becomes the all new Map/Sonar split page, then Sonar, etc. This allows quick access to a feature many anglers will use each time they are on the water.


The 178C comes with 6 main pages
(This shot is in black & white, but in reality all the pages are in color)


Ease of Use: Garmin units have always been the most user-friendly product we've used. Everything is well organized and comes with a detailed and straightforward owner's manual, along with a table of contents and an index to quickly find what you necessitate. The electronic unit itself has good labeling and tabs make navigating through them without getting lost uncomplicated. Straight out of the box we were able to employ the 178C with only reading the quick reference guide that provided instructions on the most useful and basic functions.  But because there are so many features and pages available, most anglers will need to read through the owner's manual to fully understand the complete range of capabilities offered by the GPSMAP Sounder.


There are two things that we thought can be improved on the 178C.  Manually entering a new Waypoint should be made more conspicuous.  Right now you can do so in a few ways that require you to mark a current position, then enter the values,  or hit menu twice, drop down to the list of waypoints and hit menu to enter new coordinates.  Not hard to do especially the first option to mark the current position, then edit from there, but if Garmin made it more obvious that would be really handy. Another thing that we miss is the default of the current GPS coordinates displayed on the Map page. In order to have the Position displayed, the data field must be set to Large or Huge, which will limit the amount of information currently on the screen.


The buttons are designed for easy operation using only your thumb


The overall unit is very user-friendly, especially the Pages that consist of all the valuable data and views that anglers will find useful. The buttons are placed in a good position that allow for quick access without reaching out of the way, especially when executing a sequence of button commands.


Durability: Made from a plastic alloy, the Garmin 178C chassis is durable and can take on unexpected impact if dropped or banged against other electronics or fishing gear. The stubby antenna is thick and extremely durable. There is no way can one snap it off unless you took some tools to it. The connections are rugged and provide a secure lock, along with the well protected wires for the power and transducer. The LCD is probably the most delicate portion of the unit and should be well cared for. With proper care and cleaning, the CSTN display will stay sharp for countless trips.


In terms of corrosion and taking on splash, the Garmin GPSMAP Sounder housing is fully fitted with a gasket that prevents any water or moisture from entering and it meets the IEC 529 IPX7 standard for waterproofing. The data card slot door is also sealed, and if water enters accidentally, it will not cause any problems because of the design of the door. If water does enter, water will be able to extract itself because the door opens from the bottom up. The card slot on the 178C isn't as nice as the 188C because you push the data card in almost horizontally, but still shouldn't be a problem because the door is nicely sealed. The guts are well protected but sea water can still get to the screws, but after months of testing there wasn't any corrosion on any of the stainless steel screws and other components. Overall we found the unit to be well built to withstand corrosion, accidental soaking, and plenty of pounding and vibration.


The data card slot is housed in a protected slot to prevent any corruption


Maps: A navigational aid like the GPSMAP Sounder combo must have the ability to support detailed maps. The Garmin comes with a built-in Worldwide Marine basemap that should only be used for general navigation, and is compatible with MapSource® BlueChart® offshore marine cartography. These maps display much detailed data such as depth contour, wrecks, navaids, obstacles, and much more.  Anglers across the world can make use of these detailed maps because one can obtain the CD or pre-programmed data cards that cover the Atlantic, Pacific, and America's regions.


While the BlueChart® maps serves inshore/offshore anglers, Garmin didn't leave the recreational folks out. The 178C also supports MapSource Recreational Lakes with Fishing Hot Spots. These maps covers hundreds of US and Canadian lakes and features boat ramps, fishing hot zones, marinas, and much more.


Map coverage -- Americas: US, Canada, Caribbean & Central America, Central & South America; Atlantic: Europe, Africa, Asia West, Greenland; Pacific: Australia, New Zealand, Pacific Islands, Asia East, Asia West


Features: The Garmin 178C has an enormous amount of features that are all useful to anglers. It's impossible for us to mention every single one, thus we'll highlight some of the more notable features.


Sounder Features: Depth/fishfinders are here to help us fish not better, but smarter, allowing us to get an image of what's below us. And what's important is the technology that's built into the unit to assist us in hunting for potentially fish holding spots.


See-Thru®: The See-Thru® feature is one of Garmin's innovative technologies that's implemented on the 178C. This unique technology allows the Garmin sounder to interpret and display where the thermocline is located and to look beyond that to distinguish the difference between structure and the thermocline to fish. Anglers always try to find this depth blindly, but with Garmin's See-Thru® technology you can eliminate the guessing part and focus on hitting that target zone.


Garmin features a new Page that shows both the GPS map and Sonar


Whiteline: Finding the right bottom can mean finding fish, especially if certain types of fish favor certain types of bottom such as sand, mud, rock, etc. The whiteline feature allowed us to see the hardness of the bottom and structure by displaying a white line as the bottom. The white line becomes thicker if the bottom is more dense while a thin line would translate to a soft bottom with sand or mud. We were very satisfied with this feature and confirmed the bottom hardness by bouncing rockcod jigs on the ocean bottom. When the thick whiteline appeared on the LCD the bottom was very hard and were felt with the jig knocking the rocky bottom. When we were fishing in front of the beach, most of the time the whiteline came back showing a consistent thin line and a soft feeling was felt as we ran the jigs down.


Navigation Features: The Garmin 178C has plenty of features that'll get you there, back, and beyond. The unit has the ability to hold 3000 waypoints that can be marked with a name and graphic symbol. In addition there's an automatically generated list of the 10 nearest waypoints either closest to you or your destination. An angler can also set 10 Proximity waypoints which will display an alarm circle when you get near either a fishing hotspot you marked and added to the list or can act as a good safety feature to avoid reefs and other hazardous obstacles.


Tracks are very useful especially when you've found a nice fishing hole and want to go over it again and again


TracBack™: This is a handy feature that helps you quickly retrace your path. The unit automatically logs your track as you move about on the water and can store up to 50 routes with up to 50 points. The unit also has the ability to keep track logs of 10,000 points. 15 tracks can be saved for future reference that consists of up to 700 track points each.  Having track logs and the ability to TracBack™ is a very powerful feature to have, allowing you to troll, drift, and target active fishing spots again and again.


Trip Computer: Many anglers like to keep a log of their fishing trips either for future reference, for fishing reports, or just information to share with other fellow anglers. The 178C has a very nice trip computer that keep tracks of multiple data such as a trip odometer, moving average speed, total average speed, maximum speed, stop time, moving time, total time, and odometer.


Trip computer keeps track of all the useful trip data


Digital Selective Calling: Digital Selective Calling, or DSC, is an emergency feature that allows you to connect your Garmin to your DSC equipped VHF radio to display, send, and receive positioning data to locate nearby anglers with a DSC capable radio. This eliminates the need to hail for help and wait for someone to respond. While DSC is activated, you can attend to injured crew or other critical needs, but should still always be within hearing range of your radio to respond to your rescuers.


Garmin GPSMAP 178C Sounder Ratings (?/10)

Construction/Quality Great built quality using a durable plastic alloy for the housing.  The product feel solid and is well put together 8.5
Performance Excellent performance from the GPS and Sounder.  The display is high resolution and very clear.  The processing speed is quick with no delays even when continuous scrolling.  The GPS receiver is quick and accurate.  The sounder along with the features enhance the overall performance to "see" what's below the boat 9.5
Price Disregard the MSRP because we found it much cheaper online, which is a good value for a high performing combination unit like the 178C 8
Features Packed with an enormous amount of features that are extremely useful for anglers during navigation and while searching for fish 9
Design (Ergonomics) The ergonomics of the unit is good.  The placement of the buttons are within thumbs reach and make easy and comfortable operations 8
Application This compact unit can be mounted on any big or small boat, and can easily handle fresh and saltwater without any problems 8

Total Score


Pluses and Minuses:

                 Plus                                    Minus

J High resolution color display L Position coordinates not default
J Quick refresh rates L Color mismatch between unit and mount
J Fast processing  
J Compact  
J GPS/Sounder split screen  
J Detailed map  
J Feature packed!  
J Easy to use  

Conclusion: Combination units are the way to go nowadays, especially when a boat's console is filled with many other types of electronics. The 178C is Garmin's all new GPSMAP and Sounder unit and is remarkably compact but still features many of the robust features found in larger units, and in some cases... more. The powerful unit has an extremely high resolution color screen that's clear and sharp and the GPS receiver is excellent in terms of accuracy and acquisition rate. There are features added to the unit which make it a powerful tool for anglers. With the 178C you can easily find your way around the water with detailed mapping, tracks and waypoints to get you from one point to another, and a trip computer to log trips. The fishfinder capabilities on this unit are also very good. Features such as the Whiteline and See-Thru® technology are a must have when anglers are searching for active fishing spots. Even though the combo unit is loaded with features, the Garmin 178C is very easy to use and it comes with an organized owner's manual for reference if needed. Packed in a small chassis and loaded with an enormous amount of features, this high performing new Garmin GPSMAP 178C Sounder unit is truly an marvelous piece of tackle, and can help you find quality fish holding structure, catch more fish, and bring you home safely every time.









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