How to make a waterproof hatch for efoil?

Hi, how do you DIY efoil builders make your own waterproof electronics case + hatch with a seal for the batterypack and the rest of electronics? Can you buy it online or do you make it your own?

I meen something like this:

Look at my post maybe you will find something useful: The best board for all diy e-foilers

The easiest thing is to buy a ready hatch for boats.
I using this seaflo 370x375 mm
I have it on two boards and it is not coming in any water and it is easy to open/close it.
I tested other hatches before i found this that was not 100% sealed.
The draw back is that it is not so light, around 0.9kg if i remember right.
It cost around 50 euro here in Sweden.

You can build it but it is not so easy to get it watertight. Commercial efoils have all parts inside in waterproof boxes in case of a leakage of the main lid seal.
Another approach ist using a round screw hatch, there are some reported to be waterproof. Disadvantage is the size of the opening, you need to split the battery and are also limmited in the size of the battery that can fit in.

Yes indeed, a round hatch is not an option because the space for the battery is to small and maintenance is not possible.

The picture of the board box above is from a homebuild board, so maybe it’s possible to buy somewhere or could it be that you can 3d-print it?

Another option i think is to make it from plywood and epoxy it to make it strong and waterproof…

If there is somebody with experince or tips how to make this?

We made our own hatch for our jetboard.

We used a glass plate to build it on.
Make sure you put enough release agent on the glass plate, or you will not be able to pull it of when cured.

1st. 3 layers of carbon.
Than a honeycomb plate (size of hatch).
Than again Again 3 layers of carbon.
We also put some pealply on top of that.
After this we used a vacuum bag (actually 1/2 a bag as we used putty on the glass plate to stick the plastic on)
The result was unbelievable strong, light, and the part directly on the glass was super flat (needed for the seal).