I would make a better size access hatch. On my Formula they put in a small access hatch to get to the port engine raw water pump. It was inside a locker. Yes, I could reach through the small hatch and touch the pump, but with one finfer. I did reach all around the inside of the bulkhead and found that I could cut a much larger hatch into the bulkhead. I put in the new hatch and when the mechanic came to swap the oump he loved it. It still wasn’t big enough for me to fit but the mechanic is much younger and also much skinnier so he fit quite easily. I am sure that I saved money by buying the new hatch and making it easy for the mechanic. And every time I have work done on the pump the larger hatch will save me more money.