"HERA" SCHIFFAHRTS & TRANSPORTGESELLSCHAFT MBH.
image by Klaus-Michael Schneider, 28 Apr 2009
The flag is a horizontal tricolour of yellow, red and white, with white “HERA” centred on the red stripe.
Brown 1958 lists H787 as Brink & Wölffel (Hera Nav. & Transport Co.), while identifying the company correctly in its index.