The main body of the ROV consists of two printed pieces, each a semi-circle with a moulded thruster shroud, entry points for cables, and holes to attach the plexiglass domes.

The making of this part has been a major obstacle in building the ROV.

My first attempt at building this part used layers of acrylic, each laser cut slightly differently and bonded together. This allowed me to create the smooth grove needed for the o-ring between the domes and the body. But it was extremely messy and temperamental, and there was no way to build the thruster shrouds.

My second attempt 3D printed these parts on a Prusa printer using dissolvable support material. While this enabled me to get the exact shape I needed, the o-ring grove isn't smooth and so water would leak. I tried using a Smooth-On coating to give the grove a smooth texture, but this got messy quickly and was also unreliable.

My third attempt printed these parts on a Form2 from Formlabs. The advantage of using a resin printer is that I can print a completely smooth surface and produce the exact shape I needed. However, I found that regardless of resin (White, Tough and Durable were all tried) the parts were not stiff and would slowly deform due to the weight the the inner robot hanging from them.

And so onto my forth attempt (the current iteration). This again uses the Form2 but this time with their brand new Rigid resin which is, essentially, a fiber glass mix. I have high hopes that this material will offer all the material properties I need.