submarine

[…] a Chorus of Sea-nymphs, who […] arrive, in a winged car, from the submarine palace of their father Oceanus.

a submarine patent

When Peterson saw the unusual pitching motion of Kent Tekulve—the submarine pitcher who threw baseballs as though they were coming right out of the rubber slab on the mound—he was the first of many who tried to change Tekulve's delivery.