1978 MA rebuild.

[DonV]

There are many "rules of thumb" for safe fuel consumption when going off shore. The one I remember most is 25% of your fuel running out, 25% for fishing, 25% running back in and 25% for reserve. I'm with Jorge, ya need to have "plenty of gas in reserve", to me 40 gal capacity would be minimum to safely take the offshore adventures you mentioned.