Early in the planning I decided that it would be a good idea to have an escape hatch in the cabover area. There are no windows suitable to be an emergency exit. I looked at several possibilities online including the Arctic Tern RV Skylight, Dometic/Heki roof lights and various marine units. In the end I decided to build my own because:
- it would cost significantly less
- I didn’t feel the need for a clear hatch to let in light since it’s right over the bed
- making it from aluminum would result in a more durable hatch than commercial units which usually include plastic parts
- if something breaks I’ll be able to fix it without having to buy proprietary parts
It took a considerable amount of time to build the hatch, however even if I had purchased a hatch I would have had to build a frame to adapt it to the curve of the roof.
I made the lid of the hatch with .032″ 6061T4 aluminum and the walls with 1″ x 2″ rectangular aluminum with a 0.125″ wall.
The hatch hinges at the front with a stainless steel piano hinge. It opens to about 135°. The lid is buck riveted. The hatch is mounted to the roof with 1/4″ stainless steel bolts threaded into the hatch and installed from inside the camper. It is sealed to the roof with butyl tape. There is no external flange.
The interior open space will be about 23″ x 16″ after the wood trim is added. Outside dimensions are 26.5″ by 21″ and it protrudes above the roof 2.75″ at the sides. Height at the centre is a little less due to the roof curve.
The hatch weighs about 15 lbs, a little less than the 17.6 lbs of the Arctic Tern RV Skylight and 24.26 lbs for the Dometic Heki 2.
The spacers that run fore and aft of the hatch have to be curved to fit the roof curve. I made each of these from two pieces of 032″ aluminum sheet bent to 90° on a brake and then curved using a Harbor Freight Shrinker/Stretcher Set. Then I pop riveted the two pieces together.
Still to be done is to trim the inside with wood for added insulation, appearance and to avoid condensation. I’ll also install a prop of some type to keep the hatch open and a latch to secure it closed.
Since there will be a MaxxFan Deluxe fan installed directly to the rear of the escape hatch I’m not planning on using the hatch for ventilation. If I decide that a bug screen is needed I can add it later.