Galley Blower

[KAM]

Just helping a friend with some minor renovations. The boat an HR Monsun has a 4 inch ventilation pipe running from an inlet below the galley sink up to a blower in the port coaming. The previous owner said it was "for the gas". It looks like it was the original installation but seems to be a bit unnecessary. I was just wondering if anyone else has come across a similar set up.

 

[KAM]

Removing the vent pipe has revealed a used mounting plinth for the original galley foot pump so despite the appearance of an original fit the vent pipe and blower seems to be yet another modification from a misguided previous owner.