suggestions on fuel tank for 20'

[FossilMan]

I would calculate how much you burn and use that as a guide. I just pulled an 83 gallon tank from my 20 MA and will be halving that most likely. For my uses and the efficiency of my motor, 40 gallons is way more than enough. The most I will probably venture offshore is 20-25 miles. Even running up the coast to Tampa, I should still be good. I used to believe you can't have enough fuel, hence the 83 gallon tank, but every person and boat has different needs. Hope that helps.