I wanted to use Spring Clips at first for holding trolling rod in Amphibear. But car roof lining is too soft for clips. I did not like the idea of Cable Tie loops as well. Instead of tightened and rigid loop, it is loose and not fixed when empty. Until finally obvious became obvious to me also.  It is easy to fix empty loop with cut away clamp from another cable tie. In that way I managed to make 2 cheap, simple and strong enough loops, to hold my rod under the sealing.

Cable tie loops in both ends and Velcro tie in the middle to fix rod to handle.