I play a lot of support gangplank (check out the account "God of Pirates" if you are intersted) and it is very strong when done correctly, but what you suggest is sucide. Your build is very weak early and that is just a waste of potential as gangplank's level 1 is among the best in the game. Also his best skill is his heal, it works wonders to bait enemies, waste their cc and trade with minimal losses. You do have a point about raise moral and zekes, a wonderful combat combination for almost any team. I suggest you try the following build:

runes: AD / Armor / MS / CDR + one crit mark
masteries: 14 / 16 / 0
skillorder: q-w-w-e after R > W > E > Q
Items: Flask - Sightstone - zekes - Triforce/Hexdrinker/Gauntlet

Although support Gangplank support is viable, your build is quite flawed.

Masteries: change to 9/0/21, keeping the 10% CDR.
Runes: Trade out gold quints and armor marks for AD quints and armor pen marks respectively. In lane, Gangplank can really do nothing but poke, so taking offensive quints and marks help with that.
Skill order: Taking three points in Parrrley then maxing Raise Morale is best.
Items: Fairly good. Dump Frozen Mallet; as a support, you should never have more than five items. You need the open slot for wards.