They used the Athanai for the scenes when they are aboard the raised Titanic. All of the scenes with the encrusted ship are aboard the Athanai. I'm not sure about the interiors, though (i.e. ballroom). But the decks are all the Athanai.
You're right, Robert. The Asturias (which had the right kind of davits) was at the breakers' yard at the time and only the starboard side was sufficiently intact for filming. But both sides of the Titanic appear in the film - it was all done with mirrors! And backwards lettering, the same technique later used by James Cameron.
The Athenai was used in the "Grand Staircase" scene with an in-camera special effect. A miniature of the Grand Staircase was suspended at the "nodal point" in front of the camera. There were at least two other hanging miniatures used in RTT with the Athenai. Check out the excellent website www.raisethetitanic.com for more information and behind-the-scenes photos. Robert H. Gibbons
The image you posted is the model coming into New York harbor. The dock scenes showing the cutting torches, etc. is the Athenai. Incidentally, there was a suggestion to take a camera to Edwina MacKenzie's home in Hermosa Beach and film her against the sky and then insert her scene into the New York arrival scenes, but the producers had run out of money and didn't approve additional expense. The welcoming boats, etc. were from the Bicentennial's "Operation Sail" and filmed in 1976. The film was kept on ice and not processed for four more years and then combined optically with the model and tugs! Robert H. Gibbons
I don't know about correct scaling, but they inserted model footage into the Operation Sail footage. I always thought it was ironic they showed the Titanic sailing under the Brooklyn Bridge with the World Trade Center towers in the background. I thought that shot looked correct, scale-wise. Hollywood miniature filmmakers usually know the correct scale for inserting model footage into live action background plates.Perhaps Ken Marschall will chime in, if he reads this post. Robert H. Gibbons
Also filmed aboard the Athenai were the stern deck scene (with flag), Pitt walking along one of the promanade decks, dinning room (doubled as staircase) for when the Russian comes aboard and the Athenai's forward deck (fo'castle) for the cargo hold cover and removel of cargo boom.
As Robert said, check out the RTT site, you will see some of my behind the scenes images on there that show painted back drops for the sets.
There a photo of the "Grand Staircase" posted by the late Jon Hollis on this message board in 2005 on the other Raise the Titanic thread. Just scroll back to 2005 and you will see the "hanging miniature" in the Athenai. If you look closely, you can see the left and right edges and of course the bottom of the staircase miniature. Robert H. Gibbons