Tremolo is one of the calls of the common loon - my favorite bird. Tremolo is also the name I've chosen for my C-Dory. (I made the custom design.) *

Current version of the loon in the first "O" I may tweak this some more but it's close. I use Adobe Illustrator to design the art.

Here's how the full logo looks.

Revised mock up with the more realistic loon.