I lost alot of mine in a sunken boat too.
Those weapons don't always need to be guns.
I would highly recommend the Cold Steel knock off of the Spetsnaz entrenching tool and some training to back it up.
Wrap the handle in duct tape to increase positive grip. Sharpen all 4 edges and practice with the sheath in place.
To the average Joe, it's a small shovel. To the guy/girl who knows how to use it, it's a quick way to royally ruin some ones day. Absolutely devastating.
Shovels | Axes Saws Shears & Shovels | Knives & Tools
Russian Special Forces - Spetsnaz GRU - Entrenching Shovel in Close Combat - Basic Technique.