Now that Marshall requires you to use their boats, I'm blind without my electronics.  What are your recommendations for the best portable?  

Bruce. I have a Garmen 140 that I attack to the trolling motor housing with a radiator hose clamp. It does not use much power and has both temp and battery charge display. It is not a color display but does a good job for about $120 when I bought it about 4 years ago. 

One recommendation is to always bring a small battery as on one trip the motor battery was too far from the motor for the depth finder cables. 

Bill Fetech

i have posted in the past that this Hummingbird RF10 in the most versatile fishfinder on the market.. it runs on 4 AA batteries and has the green transducer that you can clip onto fishing line and drag behind boat,it floats, OR clip it to a reel and drag behind boat OR cast it out to see depth across to another area and real it back slowly to read bottom,, also great for bank fishermen since it is castable,, self inclosed and very portable and good screen picture,, been using mine for 8-9 years and not one problem.. you wont be dissapointed.. you ask what is the Best Portable Rig?? here it is

Bruce, both of the above are great options. If you're a "do-it-yourselfer," here's another option:

http://texasfishingforum.com/forums/ubbthreads.php/topics/10323106#Post10323106

It won't take but a little tinkering to make any electronics portable. A hose clamp to mount the transducer to the trolling motor, a few zip ties that will run the transducer cord up the trolling motor shaft (cut and removed at end of day) and a small deer feeder battery that will easily run the graph for a weekend without recharging. I would put a ram mount on a short piece of 2x6 and you're all set to keep the graph stabilized on the boat.  I used this same setup to allow switching between pond prowler and float tube and know it's easy to remove when finished. 

Now you've got the power and edge that regular graphs offer and the mobility to use it anywhere by simply expending 3-4 zip ties a trip. 

Originally Posted by Phillip D. Chapin

i have posted in the past that this Hummingbird RF10 in the most versatile fishfinder on the market.. it runs on 4 AA batteries and has the green transducer that you can clip onto fishing line and drag behind boat,it floats, OR clip it to a reel and drag behind boat OR cast it out to see depth across to another area and real it back slowly to read bottom,, also great for bank fishermen since it is castable,, self inclosed and very portable and good screen picture,, been using mine for 8-9 years and not one problem.. you wont be dissapointed.. you ask what is the Best Portable Rig?? here it is

out of all the great items i have seen here,, the Hummingbird RF10 is still the most compact portable i have seen.. folds up easily in one small self contained unit , no battery lugging, no instal and break down , just open up and ready to go ,, even if your boat hopping at Marshal 10/10,, PLUS great for the bank fisherman since transducer is castable if needed

On the Hummingbird RF-10. How do you replace the batteries in transponder?  Do you connect transponder to a charger?  If so can you replace the rechargeable batteries in transponder easily?  Thanks.

on the Hummingbird RF10 transducer.. it is sealed , you replace it when, or if it ever runs down... it has 2 very tiny prongs on bottom that only activate it when in the water.. i have had mine for over 8 years and it hasnt ran down yet.. under the main unit there is a small storage where i have kept an extra one but havent needed it in all these years.. you can buy just the floating transducer by its self if you want,, also the AA batteries i put in main unit last me at least 2 seasons... maybe longer, but i just change them anyway...

here is same transducer, but with a watch, it actually works great too, i had one of these before the RF10 but my fish buddy kept complaining that he couldnt see it in the back seat, so i stepped up to the RF10... oh i guess i forgot to mention this is all wireless.. which makes it even better,, this watch would be sweet for the bank fisherman!!!   GREAT CHRISMAS GIFT..  i can attest from years of use that these really do work, and work very well..the image on the RF10 looks just like a standard fishfinder screen,,,,, the new ones even have temperature.. you can go to You Tube and see some of these in action... one last thing,, i saw one guy on You Tube using one of these, and if you look on the above picture you will see 2 holes in the floating transducer,, one hole for clipping to drag or cast,, the bottom hole this guy had tied on about 3-4 ft of line with a jig on it,, he would cast it out and reel it back and it showed on the screen when he was over a brush pile he would stop it and wiggle it and was catching crappie using the transducer to spot the fish AND as a bobber   unique and very effective

Thanks for all the great suggestions!

That's a terrific idea, Kelly!