Here is some basic info:
Coax relies on the center conductor current being opposite and equal to the "inner shield" current. That means the magnetic fields are cancelled and no (or not much) coax radiation, EXCEPT for the potential issue of the antenna causing some "outer shield" current NOT balanced by the intended currents. That will radiate, and is typically undesired. It is stopped by common mode chokes AT the antenna base. Could be a simple coil of the coax or the use of ferrite, such as mix 61 for vhf. Ferrite at the radio is not called for. Twisting one coax with another coax is not called for.
Twisting the TWO power wires, plus and minus is generally a good idea, but usually not necessary.
But what is going on here is the intentional radiator, the Tx antenna, is far away the most powerful source of the signal. And, its being blasted into another, resonant VHF antenna nearby. Either that has to stop with better spatial positioning, or the victim receiver needs better spec for RF blocking. And, that could be tough. The front end RF filter will likely not provide any attenuation to a signal just 1% away. The entire marine VHF voice band is about that wide. So, the RF gain circuit is getting hit with high levels of off-channel, but very strong voltage levels. It goes non-linear, making dozens of unwanted additional signals inside the receiver. One or more of those makes it to the speaker as unwanted noise, clicks, or even a reduction in intended channel sensitivity. Its akin to pulling out a splinter in your own finger, while someone is hitting you with a baseball bat. Not optimum!