Since a single hull houses the majority of Proteus' electronics, its reliable operation and consistent sealing is very important. The additional requirement of making the hull clear to mount cameras inside of it makes design even harder. Early in the process, we agreed to undertake the risk of a novel sealing method on the hull in exchange for the ability to remove the hull while keeping the electronics running. Thus a lot of Proteus' functional advantages come from a well-built electronics hull.

The clear acrylic hull is assembled from two separate parts: the front dome and the hull proper.

The forward looking camera sits inside the clear acrylic dome. A ``dome flange adapter'' is epoxy sealed to the flat surface of the dome. The flange adapter ensures a perfectly flat sealing surface, something not possible with dome's flange directly.

Two ``hull sealing collars'' are similarly epoxied to each end of the hull. The collars have o-ring glands on its sealing face for the dome and endcap seals. The hull collars and the dome flange adapters have matching holes for screws to create the pressure seal. This face sealing method has proven reliable as long as the collars and adapters are correctly epoxy sealed to their respective hosts.

The flange adapter and both sealing collar have key notches cut out. These align along an external aluminum key beneath the hull to ensure the correct insertion orientation.

Endcap

The electronics rack is cantilevered from the rear endcap. To seal, the hull slides into the endcap to form a face seal. Therefore, opening and closing the hull has no effect on the electronics.

Previous vehicle designs have mounted the electronics hull directly to the frame. The bore seal endcaps used by this design required a substantial amount of force and angular movement to install and remove. We chose a face seal method, because unlike a bore seal, face seals only require on-axis force to compress the o-ring.

The o-ring gland on the sealing collar is fastened against a flat face of the endcap to seal the electronics hull. Latching of the sealing collar to the endcap is achieved through a unique two-part fastening system that accepts screws driven between the two pieces to clamp the sealing collar to the endcap. The face seal and latching system design benefits the Proteus by supporting the cantilevered rack, allowing for low-force installation of the hull, and shortening assembly time through supporting power-driven installation of the latching screws.