That slot thing is a shackle key. I sail and those come in handy when you can't unscrew shackles with your fingers. Personally, I wouldn't alter the knife. I've got boat knives that have actually appreciated in value. Shackle keys work great for wing nuts too.

Instead, after carrying a all sorts of knife options over the years, I opted to use my favorite kitchen pairing/boning knife...had a drawer full of them already. Walmart kitchen knife section has some seriously strong knives that even include sheaths, and food grade plastic handles. I made my sheath from PVC and a heatgun.

Logic being, kitchen knives are made for daily use, are easy to clean, and hold an edge for months. I use mine for gardening, pruning trees, hiking/camping...it's just a plain old Chicago Cutlery boning knife with a wood handle. Better than any "outdoor" knife I've ever owned, and super easy to replace if lost/broken.
If you've ever looked at a "Mora" knife, a low end kitchen paring knife is a step up in utility. (i'm not talking about thin and springy steak knifes)