Definitely Bos Kalis - logo also on the wheelhouse.

Perhaps this BETTY?
Damen PushyCat 42
built 1972 Damen Shipyards Hardinxveld BV (Yd 437)
M6cyl, 235bhp Caterpillar D334

1972 built as BETTY for Van Hattum & Blankevoort BV, Beverwijk
1977 sold to NV Hollandsche Aannemingsmij Zanen-Verstoep, s'Gravenhage
later taken to Richard Bay Six Consortium Ltd, South Africa for port construction project, and then lost sight of.

This could well be the same one:
http://www.shipspotting.com/gallery/photo.php?lid=127957

Hi Peter,
Yes, the dredger HENARES was working on the mouth River Mahury, to keep the depth in the fairway to Degrad des Cannes berths.
Regards,
Yvon

The flag looks like BosKalis

Was ther a Dutch dredging company at work there at the time? It's a while ago now.