boat windows are a good idea here. Typically they have a welded metal or aluminium frame and an inset of 6mm hardened glass. Some have a sandwich of several layers of lexan glued together. They come in all shapes and sizes, and can be custommade relatively cheaply. You can get ones that open from the inside. They have to be sturdy since at sea they need to be able to withstand a wave of several tons of water coming at them at full speed.

Good luck getting through that.