The movie was surprisingly accurate on one point, though they didn't know it at the time. Computer displays show the Titanic resting at a depth of 12,347 feet. When the wreck was discovered in 1985, it was resting at a depth of 12,415 feet.
When the camera pans across the Titanic just after it surfaces, moving from stern to bow, the model builders inserted a gag; between funnel 3 and 2 (accounting for direction of camera travel), a miniature crewman works a hand pump as fast as he can.
The DVD sleeve cover notes that this movie was "made five years before the actual discovery of the Titanic's whereabouts in 1985." Aside from one of the funnels, the R.M.S. Titanic is largely intact in this movie. Some survivor accounts described the ship breaking up at the surface when she sank, as depicted in Titanic (1997), but the general consensus in 1980 was that she sank in one piece, as depicted in A Night to Remember (1958). The discovery of the wreck confirmed not only the breakup of the ship, but the extent and magnitude of its destruction.
A model of the R.M.S. Titanic was built for $350,000. When it was finished, it was too big for its tank. A bigger tank had to be built, for $6 million. That tank could hold 40 million liters (about 10.5 million gallons) of water, and was built next to the smaller tank, which had been used for several movies. Reportedly, the total cost was $1 million less than the cost to build the original R.M.S. Titanic. Adjusted for inflation, the cost would have been over $180 million as of 2018.
The 55-foot model of the R.M.S. Titanic used for the refloating scenes was constructed and first floated at CBS Studio Center in Studio City, California, before being shipped to Malta for filming. Its maiden sailing took place in the Gilligan's Island Lagoon.