Anyone using a depth finder?

A few people in my fly-fishing club use a depth finder designed for float tubes or pontoon boats; it has a small console and then a sensor that dangles straight down. Called the Hawkeye 3300P or something like that.

Does anyone use this tool, or another similar one? I’m concerned that you would have to be more or less stationary to keep the sensor under the boat, plus there would be more drag.

I’m thinking a depth finder would be useful for staying over good striper water out here in the California delta and bays near San Francisco. If you have one, what do you use it for? Thanks!

Depth Finder…
What are you planning on putting in on? I just ordered a Hummingbird PiranahMax 20. It appears to come with a sensor that should mount to a motor. I’m putting it in the kayak so I’m going to switch the transducer to a through-hull type, Hummingbird will trade the transom mount for a through-hull for just the cost of shipping if never used. I like this idea better - I’ve been fishing alot in the Delta lately and the thought of having anything else in the water besides my paddle to collect weeds and whatnot was not pleasant.

For a more portable system I have seen something that will clip on to the side of a boat etc. screen on top and transducer on bottom these are mounted into or on a rod that will keep it straight down from the screen. The only other type I’ve seen is either the wireless type or the one that comes with like 30’ of wire and is meant to be dragged behind you.

As for use of it I plan on using it for two reasons 1. to locate structure that might hold fish ( drop offs, flats, trees, etc.) and 2. to help locate bait fish which should help keep you in the stripers.

Let me know and I’ll try to help more. The Hawkeye looks like it is either mounted on a rod or can be mounted to a rod but I haven’t seen one in person.


I got a Hawkeye and sent it back. It does show depth but no bottom detail- it’s display is like those cheap 5 dollar hand held video games that have fixed images that show up at different places or times. You will not see a reef or hump, just a depth and an image designed to indicate what the bottom is composed of- rock, muck, etc, but you can not see a log, etc. Also, the cable and transducer are relatively bulky. I also got Humminbird smart cast wrist mounted, (as you can tell, I like toys) It shows bottom detail, is very compact, but you have to move very slowly when trailing the transducer. It would work well for a float tube but it did not work when covering a lake with a canoe.

Smart cast
Thanks for the input on the Hummingbird Smart Cast I was concidering getting one for fishing Lakes. Do you think it’s worth it?

I am usually in the Boundary Waters traveling and the Smart Cast just does not work well when you are moving. One day we had made our destination and were working the lake. Even then, you had to move very slowly. I varied how much line I let out. Too much line and the transducer wobbled more, ruining the signal. given how slow you had to move to get it to work, it was pretty marginal in value. If Humminbird would make a suction cup attachment so you could stick it on your canoe and keep it from wobbling, then it might be worth it. As a counterpoint, I bought it after reading a thread here where people did like it. You could look back and see if you can find that thread in the archives.

Their great!
Not so much for finding fish but rather the structure which attracts them.Good luck!

What about Bottomline?
Just got off Cabela’s site , what about the Bottomline products? they say you can clamp them to almost anything, canoe,dingy,dock,ect. Has anyone used this? How would you rate it?

A FF is great for finding structure where fish like to stay. Also there will be times where you might be paddling over fish and the FF will tell you how far down the fish are. Now for fishing mostly lakes I would look at a FF with a sidefinder transducer. This will help you mark fish that are hiding along the shoreline. But I wouldn’t use a sidefinder in saltwater.

Good advice and discussion guys; I’m
just getting back to this post now that I actually have a boat. I went ahead and got a Feathercraft, so I’m working with a thin rubber hull that ought to work well with a through-hull transponder, if I understand correctly how those work . . . you attach them inside a typical plastic or fiberglass hull, and they read the depth from there, right?

On the Feathercraft I think the trick will be to get the display properly mounted on the deck. I’d like to be able to use the depth finder and the spray skirt at the same time.

Freediverca, can you give any more detail on which transponder you have and how it is set up? And anyone else who has this kind of rig? Thanks!

Meanwhile, here’s the happy result of my last trip out on the delta:

Shoot thru the hull
I use a portable FishEagle 320 ? its potable suction cup transducer works fine inside the hull of my canoe. Just keep a puddle of water under the transducer. Suction cup really isn’t needed.

Any fishfinder is portable with a battery.

Smart Cast
I have had the smartcast for a couple years. I use an 18" piano wire leader clipped to my stern toggle. No issues with loss of signal but you are limited to “seeing” what you just passed over. I mostly use it for finding deep channels to play with Catties.


Smart Quest onboard?
Anyone played with trying to mount the transponder inside the hull? I once saw where someone was going to try. Anyone aware of results?

I have one. I like it within it’s limitations. It’s portability and ease of use are big pluses but as mentioned above the slow speed that’s required makes it limited.

I currently have my transponder attached to a 3’ stainless rod&reel. I can drag it behind me or stop and cast and retrieve it in any given direction.

I confess that I don’t use it often as I normally fish the marshes for redfish. 90% of my time on the water is spent in 3" - 3’ of water. My paddle is the most common depth finder I employ. It’s very accurate and I always bring it. ;o)

Transducer inside hull
I have my transducer shooting thru the hull of my OK Prowler. You must make sure if your going to hook up the transducer inside the hull that there are “NO” air pockets between the inside and the outside of hull. On most plastic kayaks like the Prowler there’s no problem but if you have a fiberglass hull you might have a problem. If there’s an air pocket between the inside/outside hull your transducer will “NOT” work.

Flyrodder, are you referring to the
Hawkeye SmartCast transponder, or some other? The SC transponder has such a weird shape I have a hard time picturing it flush against the hull.

If it would work, that’d be my preferred scheme, just checking the depth on your wristwatch while casting or paddling, and nothing to attach to the deck.

If I recall correctly…
(Yes, I frequently begin with a qualifier…)

the guy who was talking about making an effort to mount the Smart Cast inboard planned to Silicone a small cup-like apparatus (petri dish?) inside his boat then hoped that the Smart Cast would:

1.) be activated by being placed in the little 1/4 - 1/2 cup of water

2.) shoot through the water, silicone, etc… as needed.

I’ve never tried it and I’ve never heard if anyone has done this successfully. IF REPEAT IF it would work well it seems like a wonderful solution and would make the Smart Cast a strong contender for best all-around depth finder.

The transducer I’m using is a transom mount from a Humminbird 200DX. But you can do the same using the Smartcast Transducer. The only difference would be you would need to put a piece of closed cell foam. Cut the foam to the shape of the SC transducer then using 3M spray adheasive on the foam place the foam in the spot where you want the transducer to shoot thru the hull. Let the foam sit for 24hours then fill the hole you cut for the transducer half way with 100% clear silicone or Marine Goop. Then insert the SC transducer inside the hole in the foam and push the transducer as far down as possible. Let it sit for 3-5 days till the silicone or goop cures and it will work fine.

You could fill the foam hole with water, this would allow you to move the transducer between boats.

Might even need the water, if this “Wet
Switch” technology is for real; here’s a quote from the Cabelas writeup: " Wet Switch™ technology automatically shuts off the transducer when the unit is out of the water."

That could be a real bummer if the transponder isn’t convinced that the glue is water . . . and my other concern is that a petri dish or similar container might be hard to keep filled in any kind of chop.

I’m kind of sounding ridiculously cautious here, but if the SC won’t work, I’ll go with one of the little flashlight-style depth finders. Hate to throw away 125 bucks, especially considering how much other stuff I’ve bought to fit out my kayak (and I thought fly fishing was bad!).

Transom mount…
The PiranahMax I ordered came with the transom mount transducer. Now I had planned to send it in for exchange however I read that it really doesn’t matter when mounted in a kayak, so I went ahead and tried it. First thing I did was remove all the mounting accessories leaving me with just the “U” shaped transducer and cable. I’m still deciding if I want to make it permanent or not so I went with the vasaline method for now. In my case I had a dense foam bulkhead(more to keep things from moving forward beyond the rear hatch) right where I wanted to mount the transducer. The bulkhead sits tight to the bottom of the kayak so I cut an undersized hole the shape of the transducer in the bulkhead. I then put a little vasaline in on the hull and a little on the transducer and slipped the transducer into the undersized hole. Undersized for me was important; the foam can be compressed enough to get the transducer into the hole but more importantly it keeps the transducer tight to the hull when allowed to expand. I’ve taken it out a couple times now and everything seems to work just fine. The temp. is off but not bad. Once I measure the difference it won’t be a problem.

Hope this helps.


Favorite tech guys…
These guys really seem to know their biz. Great article.