Welcome to iboats.
Dual cable? Find out if it is a dual rack or rotary system then order the replacement cables from the iboats store.
http://www.iboats.com/Boat-Parts-Accessories/dm/*******.660257962--keywords.steering%20cable--searched.1--session_id.665198906
I gave you the proper link for the replacement rack cables. The 13 denotes the length and you should replace them in pairs. iboats does carry them.