British Seagull Drive Spring Replacement

This is designed to be a replacement insert for British Seagull propeller shear springs.

The idea is that, when printed at 100% infill, it will be strong enough to take the drive force from the engine, but will shear across the print lines if the propeller hits an obstruction.
In theory, it will be much cheaper than regular springs, and it might be worth having one or two in your boat just in case the spring goes, as backup.

I've tested this and it works well to drive the propeller, but I haven't yet crashed the propeller into anything so I can't say for sure if it will shear in practise.