Welcome to CF!
Our boat, a St Francis 44:
Fuel: 2 X 53 gallons (each engine burns .67 gph @ 2800 rpm
; this equates to around 6.5 knots on 1 engine, assuming reasonably flat water and little wind
, so theoretical range under power is about 1000 nm's, running 1 engine) We always carry 2 - 6 gallon emergency
jerry cans, though.
Water: 2 X 50 gallon tanks (with Spectra 16 gph watermaker); with 2 on board and running "normal" daily use, that lasts us about 5 days without trying to conserve. Of course, with a watermaker
, one just becomes less conservative -- we really don't worry about it. We know that if we had to, we could get by on considerably less, but that would mean fewer showers. We both like to go to bed
Holding tanks: 2 X 45 gallon tanks; with just us two on board, we tend to just use one toilet and the 45 gallon tank is good for about a week. If we had to do so, we could switch to the other toilet and go for 2 weeks, but we've never had to do it.
There's no doubt in mind that if you're in no discharge waters, the small size of many holding tanks is a limiting factor. If you can choose, don't skimp on the holding tank!