With items picked from the "metal area" at the Meredith Transfer Station plus maybe another ten dollars for items from the local hardware store, you could probably rig up a boat hook loop just like the one in the photo ......... and for the next 20 years, impress all your boat passengers by informing them how you didn't have to spend a lot of money for your boat hook/loop.
Quote: "Say ...... you know this here $125 boat hook/loop ...... well, guess what ..... it only cost me ...... like $8.17 ...... and it works just as well as the one for $125 ...... you know what I mean!" .....
Fetch a discarded roof rake from the dump, install some hardware store items like a stainless cable loop...... and you are good to go hook a dock!