Humminbird power cords are 6' in length. You can't order a 10' version.
The only "10" you got was the cord model name.
The PC-11 and PC-12 are 6' in length also.
Humminbird Helix 12 CHIRP SI, 1198c SI, 1198c SI, ONIX 10 SI NT, Helix 7 CHIRP SI GPS G2, SOLIX 12 SI, 360, RC-1