Equipping a Boat for Bottom Fishing

Deciding on a Manufacturer

The major marine electronics players are Furuno, Garmin, Raymarine and Simrad. For simplicity the selection was limited to Furuno, Garmin, and Simrad (Raymarine seems OK, just needed to narrow the field).


Garmin has lots of products with advanced features and great connectivity.  Unfortunately, for the areas of my interest, there were some negatives.  Their side scan transducers are huge!  I was told by an installer that they may affect boat performance.  Also noted was the down scan image is from stitched together side scan images. Finally, the MFD didn’t quite fit in the flush mount area. It just didn’t work for me.

That leaves Furuno and Simrad.


I have used Simrad on my last 2 boats.  They were the initial front runner but I had some reservations.


My current MFD is the NSS16 evo2.  It has a large, bright display and a user-friendly interface.  The 4D radar is great, detecting markers as close as a few feet.  Simrad autopilots have a top reputation and mine worked very well in all sea conditions.  Their structure scan is very effective up to about 100'. You can map the bottom and save the photo-realistic map for use on future trips.


All the above has been improved with their next generation products.  The NSS16 evo3 has been improved with an even brighter screen and higher processing power. That’s good because the evo2 slowed noticeably when using Navionics maps (the internal maps ran much faster).  Simrad introduced structure scan 3D.  The bottom view can be manipulated on the screen in real time giving a very intuitive approach to interpreting side scan images.  Simrad tech support told me it would work down to about 200’.


Based on these improvements, Simrad had the best MFD as far as viewing is concerned.  However, there were some things that Furuno offered that kept me coming back to them.

To make a decision, I needed to go over all the products offered by the companies, selecting those of interest for a comparison.  From that exercise I realized how deep the Furuno technology is.  Furuno has significant business in the commercial and military markets.  They make systems to survey the sea bottom, enhance commercial fishing productivity and equip ocean going ships. 


The commercial equipment is very expensive, overkill for sports fishing.  However, some of the advanced technology makes its way into the lower end products at a more reasonable price. Furuno’s 3D multi-beam sonar (DFF3D) is one example.  It allows 3D mapping at much greater depths (900’) than the Garmin and Simrad offerings. 

Furuno has the best radar technology and a decent auto pilot.  They fall slightly short on recreational market MFD display technology.   Their largest new MFD is slightly smaller than the NSS16 evo3.  The display is not as bright and has a lower resolution.  Larger displays are available but at a much higher cost.


Weighing all the tradeoffs I made a final decision (several times).  The final decision was to go with Furuno.  The next step, putting together the BOM.





The following is the BOM (Bill of Materials) for a recreational fishing boat focused on bottom fishing:



The multifunction display is a key component. Considerations involve display size, readability, ease of navigating menus and included functions. The Furuno TZTL15F is a great choice. This is a 15" display with built in GPS, maps, fish finder and wireless LAN.


The MFD is completely touch screen. The option of adding the additional remote control unit (MCU-004) should be considered for use during rough seas. Also available is an external microSD card reader

(SDU-001). The only built-in SD card access on the MFD is located on the BACK of the unit.


The integrated fish finder is dual frequency (50kHz/200kHz) non chirp. This is adequate for cruising and general use. For serious bottom fishing one should take advantage of the advanced networked fish finder boxes.




The latest development in searching the bottom for structure and fish is 3D scanning. All the major manufacturers offer a product. Furuno has the DFF-3D. The DFF-3DNetwork Multi-Beam Sonar provides side scan, down scan, real time and 3D sounder history. The last feature is advertised to give a 3-D view of the whole water column including bottom structure and fish. The view can be manipulated on the touch screen giving multiple perspectives. Using a longer wavelength (165kHz) and 800W of power results in depth penetration to almost 1000'. This puts it in a class by itself. Unfortunately, the 3D data can not be stored on the MFD. That requires an external pc running some very expensive software (TZ Professional, PBG module). The included 3D sounder history should be adequate for serious bottom fishing.


Complimenting the network fish finder is a conventional sonar unit. The chirp (Compressed High Intensity Radar Pulse) fishfinder from Furuno DDF-1Dallows high sensitivity viewing of fish and bottom structure to great depths (1,200m/3,900'). The image from this unit is the traditional two dimensional colored view of what is under the boat. It takes some experience to interpret the data. Fish show up as "arches" in the water column. Hard bottom generates a thinner line than soft bottom, etc. With the proper transducer (B265LH) this unit provides bottom discrimination. The display will show the bottom type: rock, gravel,mud or sand. This is useful as each type of fish has a preference.




Radar is essential as an element of boating safety. The fishing application is--finding birds. The DRS6A-NXThas the resolution to identify diving birds. When fishing higher in the water column, birds identify schools of bait under attack by predators. Usually one finds dolphin, tuna, mackerel and more feeding while birds dive for scraps and wounded fish. Of course this is not bottom fishing. However, catching a bonito or other tough skinned fish to use as bottom fishing bait can lead to good results.



Often anchoring over a good number is required to fish it properly. This is especially true when chumming or when the current is strong. A mechanism to get the anchor to the bottom quickly is essential in positioning the boat over the spot. Free fall windlasses make this task manageable. I prefer the Profish 700. The anchor goes into free fall after holding the deploy switch down for a few seconds. Make sure you have enough anchor rode. For a 30' boat try 300' of line with a 30' chain. Based on an excellent video review of anchors I am using a spade anchor.




An autopilot makes long runs to the fishing grounds more endurable. In SW Florida the grouper spots are 25 to 60 miles off shore. For outboards Furuno offers the Navpilot 711C/OB. Depending on the engine configuration, a hydraulic pump may also be required. For boats with computer controlled steering (i.e., Helm Master) an interface unit may be required.


Trolling is also enhanced with an autopilot. The can execute patterns to cover the fishing grounds more effectively. The 711C has the sabiki mode making bait catching easier. Finally, if no other boats or hazards are in the area, the autopilot can be used to keep the boat running straight while boating a fish.



If you have ever been caught far off shore in an unexpected storm you know the importance of weather awareness. I highly recommend getting Sirius/XM installed. All the major manufacturers offer this capability.

Once installed, weather information is sent to you every 15min via satellite. Storm tracks, lightening, wind speed and direction etc. are displayed on the chart as an overlay. You can see how far a storm is from your current location and what direction it is going.


For the Furuno MFD an antenna (SRA-50) and receiver black box (BBWX3) are required.