but there's also a shipping man's answer:
Both of these designs are made to seal and keep the water outside. The design of Nautilus is more modern and still some 30 years ago the portholes of the ships were designed accordingly.
When I become 15 years of age, I finished the school and started my career (luckily a short one) as a sailor. The porthole of my cabing was just the same type as the original design of Nautilus. Ref. 3712 was the last watch built according to this design. Now after some 40 years in shipping, the designs of Royal Oak and Nautilus contain my life experience and a lot of memories. No wonder that I love both design - equally much.
Best, Kari