Thru-hull Ducer Rigging

[TooFly]

There's an existing Garmin thru-hull ducer cable in the boat now. I wanted to use it to pull the new thru-hull ducer cable forward to the console. But the old cable isn't budging. So do I need to pull the console off and fuel tank out to run the new ducer cable from the bottom of the hull to the console? Seriously?

My boat is a 1978 20' CC, BTW.

Thanks,
Paul