Boatswain’s Mate Chief (BMC) SWE Practice Exam 2026 - Free Practice Questions and Study Guide

Tuning a boatswain’s pipe depends on how the air columns in the two bowls vibrate. By adding a small, secure mass inside each bowl, you change the way those air columns resonate, which shifts the pitch toward the desired note. Using a bowline knot with a short length of rope placed in each bowl gives you a compact, stable weight that stays in place and can be adjusted easily. Water would slosh and leak, sand or rice can shift or clump and be hard to control, but a bowline provides a repeatable way to add damping mass without mess or movement.