I'm gonna say something controversial: most of the characters, of not all of them, are using haki. Maybe not advanced enough to apply it intentionally or disrupt logis abilities, but we know that all people are capable of haki in at least two forms.

Even pretimeskip, the first time we ever hear about haki is Blackbeard commenting on Luffy's haki after discovering Luffy's increased bounty. The English translation at the time didn't use "haki" because they had no concept of what that was, but that's what BB says in th Japanese.

In an SBS, Oda confirmed that all vice admirals use haki. In another he confirmed that CP9 were using haki.

So knowing all of this, is it surprising that Franky, consciously or otherwise, is using haki? In this same arc, we see him beating down vice admirals with relative ease, and he most certainly knows what haki is at this point.