Replacing a hatch cover

So I am a kayak guide and need access to some equipment while on the water. I own a Prijon Barracuda and the day hatch on it is too small to put things like my first aid kit in and phone storage box in. So I want to get and install a larger day hatch. Any suggestions about switching to a larger hatch cover and what would be a good option? I am looking to get around a 9" hole to be able to get the things I need in/out. Any input on changing the current hole size without damaging the boat? Any advice appreciated.

I wouldn’t
Plastic boats aren’t the easiest to work with. They cut Ok, but finding a way to seal it afterwards can be hard. harder yet if the boat has seen some sun, so the plastic has started degrading (and I don’t think the barracudas are still being made, so likely this has seen some sun).

Instead, why not look at alternate ways to stores things. Use multiple smaller dry bags would be a start. Or look at storing some gear in other hatches or in the cockpit with you. For example, there is only limited first aid you can do while on the water, so putting most or all of the first aid kit into a main hatch may work just fine.

I did it
I put a 9" round hatch in the bow of my Dirago 12.

Had to make a bulkhead, make a level platform on a curved deck, etc.

It worked, but was a royal pain to do.

Next time, I’ll just buy a boat with bow and stern hatches.