double-wound strings

[Clyde Hollinger]

Friends,

Today while tuning a 1956 Baldwin grand piano (is F a model
designation?) I noticed it had no double-wound strings.  Single-wound
strings the whole way to the bottom, unless I wasn't seeing straight.
So what's the deal here?  Are double-wound strings really needed only on
little pianos that have such short babies down there?  Just wantin' to
know.

Regards,
Clyde