wide port alteration stbd alteration not allowed as rule 19 applies.
Wide port alteration is not applicable as per rule 19(d)i, so u have option of altering to starboard only, so broad alteration to starboard will be best answer for this
Flame arresters are used:
to stop the spread of an open fire
to limit the spread of an explosive event that has occurred
to protect potentially explosive mixtures from igniting
to confine fire within an enclosed, controlled, or regulated location
They are commonly used on:
fuel storage tank vents
fuel gas pipelines
safety storage cabinets for paint, aerosol cans, and other flammable mixtures
the exhaust system of internal combustion engines
Davy lamps in coal mines
overproof rum and other flammable liquors[2].
(I think its not flame screen but flame arrestor screen)
Flame arrestor screen: A mechanical device installed on a storage tank or portable container nozzle designed to prevent the build up of flammable vapors and quickly extinguish a fire in the container by rapidly dissipating heat from the fire. It is made of double mesh wire and extends inside the container from the nozzle.