The Seaview routinely fires torpedoes, yet when viewers see a view of its underside, there are no visible outer hatch openings for them to be released from even though there are outer hatch doors for the Flying Sub and diving bell.
Any time the Seaview dives below 600 feet, the sea should be completely dark. Visible light does not penetrate the ocean below that level.
Often the Seaview is seen to surface by shooting up out of the water at a steep 45 degree or steeper angle, then crashing down horizontally to the surface. No submarine behaves like this; if it did, half the crew would be killed or severely injured each time it happened.
Throughout the series, shots of the Seaview near the ocean bottom always showed massive rock formations and vegetation. Although this gives the audience great views, most of the worlds ocean floor is simply endless flat sand.
Adm Nelson throughout the series wears the sleeve insignia of a full admiral (a four-star rank) but his shirt collar shows only the rank of vice-admiral (three stars).
Despite being on a ship that is routinely rocked side to side, nothing is ever secured on shelves; items are just placed there and would be a hazard during their numerous adventures.
Strangers are routinely taken aboard the Seaview and are left free to roam around unescorted, despite the ship having nuclear weapons.