Rotterdam-area is great for shipspotting but the problem is the position of the sun.
In case you stay at Maassluis, it is always opposite of you, so bad pictures.
Crossing with the ferry to Rozenburg is better.
Two hotels at Rozenburg: Hotel Rozenburg and Hotel Pico (have not been there myself).
At Rozenburg you can sit along the New Waterway near the the ferry-landing.
Hotels on website www . booking . com (type in the name of the town: Rozenburg, Maassluis, etc.)
Staying at Rozenburg and owning a car give you also to possibility to drive to the far end of the "peninsula": there you see Europoort and New Waterway.
Take a look at Google-Maps for orientation.
I must correct you Pieter - Maassluis is excellent for morning photos!
By late morning you have to cross over on the ferry to catch the sun.
But at the Rozenburg ferry there there is to much background clutter for nice photos imo.
So photographers used to walk south east along the footway down to radar post 8 where there is a background screen of trees which is much more acceptable. At this point there is a small lay by where local photographers used to take photos. Now it is some years since I went there!
If there is rain forecast and you have no car - best to stay near the cafe at the Rozenburg ferry and hope for an improvement and get good light until the evening.