Darcy
No W in Slovak alphabet but when used in a surname it does give that (Slovak) V sound. Yes, it is possible that a German shipping clerk wrote the surname with a W instead of a V as there were some WRABELs coming thru Ellis Island.
www.ellisislandrecords.org An English letter Y is a J sound.
Few sites for research:
www.iabsi.com/gen/publicwww.helenezx.homestead.comwww.cgsi.orgwww.slovakinstitute.comwww.slovensko.comhttp://slovakia.eunet.skwww.surnamenavigator.org