Strange looking underside of 737
Not sure where to post this so I'll have a go here. I work in ground ops and noticed the other day that the belly of a 737 at around the area where the wings meet the fusalage had a strange 'rippled' look to it, almost like the effect you see on sand when the tide is going out. I mentioned it to one of the crew who was doing his walkaround who told me it was nothing to worry about and off he went. Just wondered if anyone could shed any light onto what this could be ? it certainly looked peculiar !