Multiple Yaks and Fishfinders

A question for those of you lucky enough to own multiple kayaks. 

Is it more economical to buy one fishfinder and set up your other kayaks with matching sets of cabling, mounts and transducers.... or is buying multiple complete fishfinder packages about the same cost?

It seems to me the display of a fishfinder is the most expensive part and you could possibly save some money this way.

Question two.  Does coiling your transducer cable cause interference in the display? 

... and a thought...someone with connections to Johnson Outdoors should suggest they produce a kayak specific Humminbird transducer with a 5 foot cable for their Ocean Kayak scupper hole. 

They designed the kayak scupper to fit the transducer why not make the transducer a little more kayak friendly.  What's the current length of the cable 20+ feet?

I use one FF across all my yaks. Easy to set up and take down. I use a RAM ball mount for the FF and the foam puck and water to mount the trans..

Z

Question two.  Does coiling your transducer cable cause interference in the display? 

... and a thought...someone with connections to Johnson Outdoors should suggest they produce a kayak specific Humminbird transducer with a 5 foot cable for their Ocean Kayak scupper hole. 

I cut my transducer cable and didn't have any issues except for corrosion when salt made it thru my wrap job. 

The RF test engineer I work with told me that transducer on newer fishfinders generates and processes the signal then sends a digital signal back to the display piggybacked over the power.  I'm still a little skeptical but like I said, I cut mine and it didn't seem to affect the signal.

I wouldn't worry about coiling creating interference.  That's what everybody does (including powerboaters).