I understand. This has to be done. If I understand, what is suggested is that I replace the cable and the "Helm" (the box under the steering wheel). Is that correct? The whole system. Does the Helm normally fail or wear out? I am just trying to fully understand the magnitude of this repair.
The "box" can wear out or can be damaged. Also the cable becomes worn, as well. Unfortunately boat steering doesn't have much in the way of maintenance because only the cable can be greased at the motor end. The helm gears are not serviceable in most cases.
It's best to replace as a system - A new "box" and cable, then you will have years of service. Buying a helm and cable separately is not cost effective. As a forum member you get an extra 5% off by using the "FORUM5" promo code.
Replacing isn't hard unless getting under the dash is difficult. First determine if you have a rack and pinion (long and rectangular) or rotary (roundish looking) system. Look at the pics in the iboats steering link Fleetwin posted to help.
After that, it's just out with the old and in with the new. One hint is to tie some heavy twine on one end of the old cable to use for pulling the new cable, makes it a lot easier. Often the old cable will have markings showing the length.