I've read some people say Franky is like Popeye (big forearms, soda=spinach, etc.), and since I grew up with exposure to Popeye (cartoons and stuff), I can totally appreciate/agree with that comparison.
While I was re-reading the Water 7 arc, I got to the scene with Franky in the bar with Blueno, and it struck me that Oda probably based him off Bluto/Brutus (Popeye's Enemy!).
I've read/noticed that Oda loves to use references from everything (Pop Culture, Civilizations, etc.) to include in One Piece, so I searched for some Popeye pictures to see if any other W7 characters resembled them. Interestingly, some of the characters do have some similarities and stuff :
"The whole cast of characters":
- Castor Oil (second guy from the left on the bottom row) is short, has mustache, and a unique hat; Corgi is short, has a beard, and a similar looking hat
- Sea Hag, Sweet Pea, Eugene similar to Kokora (by name only, since Franky calls her hag or something I think), Kid That Hangs Around Kokoro (forgot name), Cat That Hangs Around Kokoro
"Eugene the Jeep"
To Note: See Kokoro Cat Above
"Popeye and spinach"
To Note: Popeye + Spinach + Large Anchor Tatooed Forearms = Franky + Cola + Large Star Tatooed Forearms
"Olive spurns Ham for Popeye":
To Note: Ham Gravy's nose is like Kaku's
To Note: Similar look and play of the name
To Note: "Evil Spy" (couldn't find his real name) and "Whiffle Hen" (also known as Bernice I think) similar to Lucci and Pigeon (well, kind of!)
Also, one of the pages I came across while looking for pictures has a interesting fact about which real-life person Popeye was based on (check out his first name…):