Hi Clayton,
In May sunset is around 06:00 sundown 21:00
in June around 05:30 down at 21:30
There are trainstations in Maasluis and Hoek van Holland, you can walk from both stations to the river. pictures can be taken with the sun in your back til 10:00
I prefer to be on the other side of the river. From Maasluis you can take the ferry to the other side. If you leave the ferry and walk 100 meters to the far right side of the ferryberth you have a fantastic view on the river, ships pass quiet close. Beware of waterdrops when ships pass fast.
When you want to see the real big ones,you need at least a bike. You have to go to the Noordzeeweg*, where you have a view at the 7th petroleumhaven Calandkanaal and on the other side of the road the river. At the end of the road 9km from Rozenburg there's an artificial hill from where you can see the large Stena ferries to England, the big bulkers, the sea and behind the big bulker berth you can see the large containerterminals where the big boxships come( unfortunately to far away to take decent photos). At the Scheurhaven, Scheurweg* you can take the fastferry straight into the center of the Maasvlakte, from there it is about 5 km to Slag Maasmond* which is the best place to be from 10:30 till late afternoon.
Names with an asterisk * can be found in
www.maps.google.com by searching: Rotterdam,and that specific streetname. There's a rulerfunction so you can meassure all distances yourself.
You can also see all places in "streetview" so you have an idea what to expect.
The places I mentioned are free to access and I have never been questioned by security.
There are some places where you have very close access to the berths, but then you really need a car.
Here:
http://www.portofrotterdam.com/nl/Scheepvaart/actueel/aankomst-vertrek-schepen/Pages/default.aspx you can find daily arrivals, in port and left. from left to right, click on the photos.
If you have more questions don't hesitate to ask.
Have fun Fred