Rocket, or something else?

Thanks guys and gals. That’s definitely what it is. I would never have thought of that, so thanks indeed for the information.

yep, that’s it, try “3 inch breeches buoy rocket” in Google. The markings look pretty unhelfulpful – everything except what it is called :confused:

Not sure it’s an aviation related object as it looks very much like a Line/Cable firing rocket.

Anne