Not important, in fact fairly trivial, but ships in those days did not have the steering wheel on them; that was a later invention (within the British Navy towards the end of the 17th / start of the 18th Century). You will notice that the next film (Golden Voyage) goes back to the straightforward rudder at the back of the ship.
shareA lot of fantasy film makers mix time periods together. Eh, to be honest I don't like it a whole lot either, but it is a fantasy after all. The vessel miniature itself looks more like a British frigate than a medieval Mediterranean vessel. People like spectacle, and the film makers probably thought it best to put a big 18th century sailing vessel on the screen than something less familiar.
EDIT; and just for the record the steering wheel was invented long before the English in the 18th century.
They wouldn't have had the budget to build a ship's deck just for this film; no doubt they had to use whatever stock sets were available to them.
The ship even changes a few times; in the opening sequence, with the close-ups of Sinbad at the wheel, it even looks like he's on a 1930s tramp steamer.
There are more on IMDb goofs. A zipper, and modern buildings. Errors like Baghdad on the ocean, floating boulders.
shareThis wasn't exactly an historical documentary.
shareBut people look so GOOD standing at the wheel of a ship! It's a great way to put your leading man into a heroic pise, while looking comparatively natural.
In a movie like this one, that's much more important than historical accuracy.