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Fishfinder or depth sounder

15K views 19 replies 18 participants last post by  Minnesail  
#1 ·
i just bought a Raymarine ST60 tridata for my c-30. the current depth gauge is dead. i few weeks back there was a thread about depth gauges and one or two people mentioned getting a fishfinder instead. i was also planning on buying a handheld gps sometime this summer. looking in the sailnet store, there are color fishfinders w/gps for little more than the st-60 tridata. which would i be better off with. i'll be mostly sailing narragansett bay, block island and up to martha's vineyard. also, any fishfinder/gps that anyone could recommend.
 
#2 ·
The only problem with getting one of the Garmin/Lowrance/Hummingbird combination GPS chartplotter/fish finders is that the wind instruments won't be able to talk to them, and can't estimate true wind speed then. If you don't use electronic wind instruments... you're home free. :)

I prefer the Garmin units, since some of their models have all of the US coastal water charts pre-loaded and they seem to have the best user interface and software of the different brands.
 
#12 ·
The only problem with getting one of the Garmin/Lowrance/Hummingbird combination GPS chartplotter/fish finders is that the wind instruments won't be able to talk to them, and can't estimate true wind speed then. If you don't use electronic wind instruments... you're home free. :)

I prefer the Garmin units, since some of their models have all of the US coastal water charts pre-loaded and they seem to have the best user interface and software of the different brands.
This is a good point. Why can't Raymarine provide functionality on their chartplotters that would let them display a wind instrument? Seem like it would be easy to do.
 
#4 ·
For me it's a fish finder

And I'm not big on fishing :p

When there is a need for knowing the depth, a depth sounder can do just that. And no more.

A fish finder provides a whole range of info like the shape of the bottom and the make-up of the sea bed (rock, sand, etc). Many of the better ones have forward-looking sonar that is also very useful.

And it can also see fish if that's of any value to you.

Andre
 
#9 ·
And I'm not big on fishing :p

When there is a need for knowing the depth, a depth sounder can do just that. And no more.

A fish finder provides a whole range of info like the shape of the bottom and the make-up of the sea bed (rock, sand, etc). Many of the better ones have forward-looking sonar that is also very useful.

And it can also see fish if that's of any value to you.
Not to mention shipwrecks, big rocks...they are fun to twiddle with. I got a monochrome Eagle fishfinder for the nav station because I could make the numbers quite large, large enough to be read from the cockpit. I kept the old, still functional cathode ring one as a backup, but really, I use the new one a lot more.

Another trick is to set the alarm for a known depth contour, like 10 metres or 30 feet or something that will stick out on a chart. Then you can follow the contour in fog knowing where you are not, if you follow, which can be quite helpful. For instance, if you find a nav aid that your DR tells you is near, and it's close to a known contour, you can be in fog at night and find it, and then literally get your bearings.

I'm no Luddite who would turn down a chartplotter, but give me a paper chart, a fishfinder (tells me when I've hit "shelly bits" or some unusual charted bottom state) and a compass, and I can usually find my way to safety.
 
#5 ·
Hello,

If you are in the market for a GPS, AND you need a depth gauge, you are best off buying a combo GPS / fish finder. On my last boat I had a Lowrance 3.5" combo unit (M68 C / Smap or something like that) that I paid $400 for and worked great. It came with detailed charts for the entire US. For my current boat I bought a similar model with a bigger screen. I paid $600 or so for it. It has inputs and outputs so I could connect my DSC VHF to it.

Barry
 
#6 ·
I've bought a fishfinder for depth measurements and have been really happy with it... Mine is a simple hummingbird unit with tri-band sonar. It gets really accurate bottom readings and graphic display is easy to keep track of depth readings to use with charts... I wouldn't recommend combo units since if the unit fails you have none of the tools, individual units are better... Handheld GPS wise if you have a data cord input/output you can use e-charts on your computer or connect it to your VHF to get lang/long info on your VHF and send DSC signal with your location...

Quick tip: If you install the transducent to your rudder instead of the hull you will avoid another hole to create problems and can get readings wider than fixed installation. My transducent is installed on the back of the rudder and I can get readings of the wider area beneath the boat by turning the rudder left and right...
 
#10 ·
Quick tip: If you install the transducent to your rudder instead of the hull you will avoid another hole to create problems and can get readings wider than fixed installation. My transducent is installed on the back of the rudder and I can get readings of the wider area beneath the boat by turning the rudder left and right...
I have a garmin fish finder. I epoxied the depth transducer to the inside of the hull under the v berth. It works great and it tells me I'm going to hit something just in time to hang on. Most fish finder transducers that I've seen are not easily mounted on my transom since it is angled and out of the water.

One other problem that I had was how to mount the speed transducer. Garmin doesn't offer a thru hull transducer for my fishfinder. I solved this by building a small solid fiberglass "transom" and gluing it to the bottom with 4200 between the keel and rudder.
 
#7 ·
I have a fishfinder, but I don't fish.

There are times when layers of floating plants will give you a false shallow depth reading. There are also times when the water is too deep for a reading. In both cases the fishfinder will show you what's going on.

The fishfinder shows a graphical history of depth, so you can extrapolate from the reading you got a minute ago. The fish finder can also show soundings at multiple depths simultaneously, so you can see the plant layer as well as the true bottom.

A simple display with just a number is nice, but I wouldn't want to be without the details that a fishfinder provides.

And lastly, the fishfinder is fun when you have kids aboard. They love watching for fish.
 
#8 ·
I wonder if a fishfinder was called sonar would more people want them ?
 
#11 ·
mounting transducers

Hello,

If your boat has a solid fiberglass hull, installing the transducer should take about 1 minute. You can use a 'puck' type transducer instead of a through hull. You don't need to epoxy the transducer or mount it in a tube filled with oil. All you need is some toilet bowl wax (about $1.00 from Home Depot, etc.). Press a wad of wax onto the hull where you want to place the transducer, then press the transducer into the wax.

I did this about a year ago. I originally planned on using the wax to find a good location, and then epoxying it in. However, since it has worked great, I have no reason to glue it down.

Good luck,
Barry
 
#13 ·
Some of the companies state in their product description that the in hull transducers work as good if not better than the thu-hull types. Toilet bowl wax sounds good. I had similar results with "shoe goo." Sometimes you have to play around with location due to trapped air in the laminate.

Hello,

If your boat has a solid fiberglass hull, installing the transducer should take about 1 minute. You can use a 'puck' type transducer instead of a through hull. You don't need to epoxy the transducer or mount it in a tube filled with oil. All you need is some toilet bowl wax (about $1.00 from Home Depot, etc.). Press a wad of wax onto the hull where you want to place the transducer, then press the transducer into the wax.

I did this about a year ago. I originally planned on using the wax to find a good location, and then epoxying it in. However, since it has worked great, I have no reason to glue it down.

Good luck,
Barry
 
#15 ·
Polysulfite caulk works very well to attach the puck style transducers for shoot thru hull aplications. It will set-up fairly solidly and doesn't flex like silicone and screw up the reading.

While it is true that these combo units cannot "talk" to your wind instruments, I'm not sure what they would have to say even if they could. The best case senario would be that you could have one display that could toggle thru multiple instruments, but I'm not convinced I would want that anyway. I like the idea of having all the data on screen right in front of me.
 
#20 ·
This thread is eight years old, so electronics have improved and gotten cheaper since then.

For my small boat I have a Lowrance Hook 4 that came with the Navionics+ chip. It's a fish finder that also shows depth, speed, bottom composition, and works as a chart plotter. It has all the US charts including inland lakes. The display is weatherproof and can be mounted in the cockpit. It was under $400.

The limitation are that the screen is small (about the size of an iPhone) and it has older networking technology (NMEA 0183) so you might have trouble hooking it up with all the other latest and greatest.
 
#19 ·
i had an apelco by raymarine until the screen got a sunburn. i need to err wish to replace it with another-- i prefer both gps depth sounder and a fishfinder , each mounted in different places on hull to allow depth info for med type mooring. gps ahead of my keel, fishfinder is under cockpit--ha ha ha helluva practical place for depth--ye can see how deep it wasnot as you wrestle of the shoal..hahahahaha
my gps depth sounder is both or either thru hull or stick to inside of hull mount and the fishfinder has a thru hull fitting already and a transducer, so i seek specific fishfinder compatible with my trandsucer.