Replacement steering cable for Twin Volvo Penta 5.7L with SX

[pwilson164]

I am brand new to boating and just purchased my first. The surveyor suggested that I get the steering cable replaced. I'm fairly confident that this is something I could do myself, but I can't find any information on what type of cable is required. I know that Volvo Penta makes cables, but I can't find anywhere I can order them from in the U.S. Do I have to use the Penta cable or is there another way to tell what I need?

2000 Larson 330 Cabrio if that helps...