The coast guard has a formula for what tonnage they give, based on the amount of time spent on the vessel.
Remember that this is Gross tonnage..( carrying capacity, a volume measurement ) not the weight of the vessel....there are calculators for this online
I believe....1 day above 25 gt will get you a 50 gt ton license...but the jump up to 100 gt tons requires ...I believe 180 days.....don't shoot me if I'm wrong on that....you can look it up on their website! it's in the CFR...somewhere in 46 CFR
You have to be actively engaged in the operation of the vessel....so being a cook doesn't qualify...who know how that happened?
falsifying time served is a serious offense..something like 5 years imprisonment and $5,000 fine.