Chord Progression ?

[Bill Atwood]

I have decided I needed to learn some music theory and get a better understanding of chord progressions. I played my first music in Hawaii on a Martin Baritone Uke. We played much of the music in the key of F and the most common progression was F-G7-C7. If I am understanding the numbering system, thats 1-2-5 or I-II-V. What happened to 1-4-5? For years, I have played those chords along to country music and sounded ok. Does most Hawaiian music follow a different pattern?

[Donny Hinson]

Sooner or later, no matter what music you play, you'll need that "IV" chord. In the key of "F", that's a Bb. There's lots of "IV" chords in Hawaiian music, too! Just for fun, try playing that old standard "Aloha Oe" without that IV chord!

[Dave Boothroyd]

Are you sure you were in F?
F,G7, C7 might, at the time you played it be IV ,V I in the key of C. Tunes do modulate from line to line sometimes.
Are you sure that the G7 was really a G7?g,b,d,f is not a bad substitution for bflat, d,f and the g as a sixth extension

If it sounded wrong, it probably was, but if it didn't, it's only the explanation you are short of- you have the right chords!
You hear chords in their context, and most sets of notes can be considered to have half a dozen chord names. Just don't worry about it. Have a look at some jazz standards and see what they do with chord substitutions, and this will seen a very small deviation from your I, IV, V.
Cheers
Dave