My great great grandfather is also Casimir (Octave) Gangloff from Alsace.
He was deported to New Caledonia and then stowed away to PNG where he married a local girl and fathered, my great grandfather Ernst Octave Gangloff.
Ernst married Elizabeth and fathered seven Maria, Hubertine, Gerard, Theresa, Ralph, Bernard and Agnes. Maria died at the age of 9 from black water fever. Agnes is the only surviving offspring. Gerard is my grandfather.
Hope this helps.