Not sure about the tank on the 34 but on the 40 the tank is baffled, which helps reduce the possibility of sucking air in a lively sea.
I agree with the previous posts about the dangers inherent in getting water and/or gunk from a low tank.
However, it's not a bad idea to find out how much USABLE fuel your tank holds. While that stated capacity may be 35 gallons, no fuel pickup can actually get every last drop. Some fuel is always going to be in the very bottom of a tank. Some sailors run their tanks "dry" intentionally and then fill them up to develop a "usable" fuel number.
On JUNO, for instance, although the stated capacity of the tank is 67 gallons, we have discovered (the hard way) that the pickup sucks air at 58 gallons.
Best wishes and Happy Thanksgiving to all,
PSC 40 -- #46