On this page you see several "water dioramas with (for most) German U-boote.
Especially Scale 1:144 is a great scale for these boats. The boats (mostly Revell) are well detailed and can be put easily in a diorama. Creating water is not difficult and is done, not with resin but, with yacht varnish*(terpentine based). By giving several layers of varnish (sometimes some paint is added to give it another color) I'm creating depth in the water.
*purchased at a construction market. A tin can yacht varnish of 0,25 litre (around 15 euro) can be used for several dioramas!
1:72 "Tegenliggers" (Traffic jam!)
U boat VII Revell
Vehicles Dragon, Academy, Revell
The story of the VII: https://en.wikipedia.org/wiki/Type_VII_submarine
1:144 "De stier van Scapa flow" (The bull of scapa flow)
U boats VII Revell
Vehicles Dragon 1:144 and Herpa 1:160
Figures Formost Herpa, Preiser 1:144/160
1:144 "Te laat opgedoken" (Surfaced too late)
U boat XXI Revell
U boat XXIII Trumpeter
Vehicles Herpa/ Wiking (1:160)
Figures Preiser/ Herpa (1:160)
The story of the XXI : https://en.wikipedia.org/wiki/Type_XXI_submarine
The story f the XXXIII: https://en.wikipedia.org/wiki/Type_XXIII_submarine
1:144 "Kano's in de Zwarte Zee" (Canoes in the black sea)
U boat II B late Revell/ ICM
Figures 3D printed Shapeways Panzers vs Tanks
Halftrack Sdkfz251 Pegasus