Fish Finder for my Yak [Archive] - Fly Fishing Forum

: Fish Finder for my Yak

06-24-2003, 08:27 AM
So, I've been envious for a while now of the guys who have the finders on their yaks. There have been many times that I didn't know if I was in 5 ft of water or 20 ft of water, due to the water clarity in some of the North Shore River runoffs. Short of dropping an anchor over I never really knew. Being able to tell if there are fish there or not is an added bonus!

I paddle a 9 ft Ocean Kayak Frenzy. Great boat for all that I do (surfing, fishing, paddling, etc.) but not all that much deck room for goodies. And I really like to be able to strip down the boat for non fishing expiditions. Therefore I didn't want to mount a hard fishfinder on board...

Enter the Humminbird RF30 Wireless fishfinder with Watch display screen. I saw this little unit a while back, but didn't see the Watch version of it until a few weeks ago. Now being a fly fisherman mostly, I didn't see much need for a castable Fish Finder. But then the lightbulb went off. What if I towed the transducer behind my kayak? So I had to take the plunge, and it wasn't even that bad at 90 bucks.

Well, I'm happy to say, that this baby works just like its supposed to. Pretty barebones fishfinder, but I mostly use it for bottom contours and depth readouts. Seeing fish is a bonus (although I have yet to catch one of these "fish" it sees). I tow it off the back on a piece of string and it reads out great while I paddle along. There is a dead spot in my paddling before I get going along, but after drifting, that the transducer is semi underwater, so the wireless part doesn't transmit. But once it planes off, it works again. It also seems to have problems at speed in depths over 40 ft, but it works up to 100 while I'm drifting along.

So all in all, its been a great addition to my yak. Can't wait to try it on my brothers small inflatable Zodiac, or my parents boat, or taking it on vacation with me next time, get my point.


06-24-2003, 09:29 AM
Nick...I'll be right behind you!
Is there an alarm for when unit picks up something (shark) larger than your Yak?:eyecrazy:

You might as well go all the way but...
...Where will you be mounting the radar antenna?! :confused:

06-24-2003, 09:47 AM
Great to hear from ya! Long time no fish. There's an audible beep on the unit for depth changes (in auto depth mode) and also for fish marked. I think it needs a field trial in Lewis bay!


06-24-2003, 09:38 PM
Nickster...A Lewis Bay sortie sounds like a winner...
I'm available most Saturdaze!
C'mon down...

06-25-2003, 07:10 AM
Alright, sounds good, but probably not for a few...busy busy this Summer Holiday Season.

BTW...I gotta get a Penguin Keyboard!

06-27-2003, 01:03 PM
Good move, almost feels like cheating sometimes. I've been curious if those wireless trannies would fire through a hull like my convention type does. Assuming it's about the same power and frequency you should be able to put in a freezer bag with some water, squeeze out the air and lay it inside on the bottom of the hull. You might need some duct tape if it won't sit with the right orientation (bottom of the puck down).

06-27-2003, 01:24 PM
Great Idea! The only problem for me is that I have a SOT and can't really get to my lower hull. I haven't cut out a place yet for storage.


06-27-2003, 04:58 PM
That's the first thing that came to mind...
Plastic deli cup with bottom cut off taped to hull...
A pool of 5 minute epoxy...No air bubbles...
Transducer held in postion until the set...
An interesting premise!

Think it will phloat?!:confused:

Where did you get your unit?

Doc Duprey
06-29-2003, 10:14 PM
...Back in the bad old days when I was getting paid to sail the briney blue...

Rather than bore a hole throught the hull , we found that if you cut the bottom off a Tupperware-type container, and epoxied the cut end to the hull, you could then insert the transponder through the removable top of the container, fill the container with mineral oil (for acoustic coupling), "burp" the lid, and it would work like a champ. Only problem might be a little bit of signal attenuation because of the hull thickness and material. Might be worth a shot though. Hmm...wonder of I could set one up in the stern of my Pungo...:devil:

Best regards,


06-30-2003, 07:42 AM
Not Coast Guard...but Center of Gravity!
I fould that stored items up front in the bow, and the little weight they added, could adversely affect the handling...the additional weight way up front would induce a carving/turning movement and control problems...sponteneous and challenging!

With that said, I'd keep the rear area open for all cargo (that will move the CG to the rear and avoid the above mentioned turn/carve moment) and consider the placement of the light weight transducer and tupperware module in a spot way up front in the bow away from your feet or, if that does not work, just in front of the seat out of the way.

CG Experiment...Put some stuff up front and go paddle...I found the control problems induced by the low riding bow made tracking in swirling currents very challenging...when the cargo was moved to the rear area, control was regained and handling/tracking was much improved.

06-30-2003, 09:59 AM
Only problem with hard mounting this unit is that it needs water to activate the sending unit. It has two metal contacts on the bottom of the Transducer that, when connected through water, close the circuitry and start the transmissions. Also, the "conning tower" of it needs to be above water to transmit the signal back.


06-30-2003, 11:08 AM
Back to the drawing board...

Nick...I was wondering what activated that little android...
Thanks for the pre-R&D input!:rolleyes:

06-30-2003, 11:31 AM
Bass boats have been shooting through the hull for decades. If the transducer is pushed into a pool of epoxy make sure it is the long cure time type, and put a brick ontop. After about a year transducers that were mounted in 5 minute epoxy stopped working reliably.

06-30-2003, 12:53 PM
You'll probably want to cut some hatches in sooner or later. When you do it would be interesting to see how the 'droid does shooting thru the hull. I rigged a conventional transom mount tranny so it sits in water and shoots thru the hull. Works acceptably well. I pull the wiring out to give it a fw dunk after each trip to try to stem the corrosion but this could really be the ticket. No wires, no worries.