I have been toying with the idea of making a DSRV of sorts. I want to take a tube that is 8 to 10 inches in diameter and about 3' long to put a video camera inside. I was doing find until I came to the part about sealing the the front of tube where the camera will sit. I need a bubble type enclosure that will withstand let's say 400'. I looked up Acrylic Plastic Viewports on google but didn't find any manufacturers. I would like to find a bubble with at least a 10 bolt flange. If i can make this work, I'll post plans and pics. Thanks for any help guys.