Complex sentence: Once a Japanese airplane dropped 3 bombs directly on the Silversides, that somehow survived and trying to escape, went into a hard dive with bow planes jammed, going deeper than the submarine was designed to survive.
Split into simpler sentences: Once a Japanese airplane dropped 3 bombs directly on the Silversides. The sub somehow survived and, while trying to escape, went into a hard dive with bow planes jammed, going deeper than the submarine was designed to survive.