I just finished cruising on a boat
, where the mosquitos in the remote anchorages
were large and aggressive.
I was on had a very simple "bug screen" contraption for the companionway hatch.
It consisted of a simple wood dowel at one end of a long continuous strip of mosquito netting, with another wood dowel at the far end of the net. The net was cut to cover the width of the hatch. The first (top) dowel was fixed to the hatch (probably with Velcro).
To use the netting, one simply opened the hatch, and unrolled the netting off the dowel, by rolling the dowel along the hatch, then letting it drop down the companionway (vertical portion) to where the hatch boards would normally be in place. The weight of the wood kept the net close to the hatch opening sides. When dropped, the net was on the outside of the hatch slides and where the hatch boards would drop. It completely covered the hatch in a long single
piece of net. This worked whether one or more or no hatchboards were in place.
It was very simply installed, effective, and easy to go inside and outside by simply pulling back the netting or rolling it up and then letting gravity drop it down back in place. Simple.