You talking rocket launcher type or those to use while actually fishing? If it's the 1st, mount them on a milk crate so you don't need to make any permanent changes (holes) to your buddys Kayak. Is it a sit-in or on? I don't fish with more than 2 poles at a time usually, and will just lay them on my lap.
Palmetto Kayak Fishing: Ultimate DIY Kayak Crate