Hey, I found one Bill Burns @
http://atlantic-cable.com/ who isn't 130+ yrs. old, but did direct me to this 1903 Roebling (as in Brooklyn Bridge) catalog here:
http://books.google.com/books?id=YCRYAAAAYAAJ&pg=PA33
Which tells me galvanized wire was available, but probably not 7x19 or 7x7. However, they are probably close enough to the 6x7 & 6x19 (with a tarred hemp core) to fool any 130 + year old folks that look at the boat (their eyesight isn't too good).
Dock
PS: Shameless plug: FDR's iceboat the Hawk will be set up & on display (missing pieces & all) as well as other complete iceboats (some 50') belonging to his uncle & other contemporaries @ the FDR library Hyde Park NY from Dec. 21 - Jan. 2.