Do you have the deck panel removed ? If so you should just be able to unhook the fill and vent lines and use these as "Handles". There should be some wedges along side the tank and a couple of 2x4's over the top of the tank , These will screwed into the stringers at a 45* angle or so .You could take out the sending unit and use that hole for a gripping point . The tank is empty ,correct? If not get as much fuel out as possible ,use a primer bulb with a long copper tube atached to it to siphon out all of the fuel.
Let me explain the primer bulb, On the suction side of the bulb use a short 6" or so piece of gas line attached to the bulb . Put a piece of COPPER tubing (usually 1/4 or 3/8) about 3' long or however long it needs to be to reach to the farthest location in tank from sending unit hole. On the output side of the bulb use a piece of gas line long enough to get to a gas can that you can set on the deck. This way is not neccesarily fast but it is effective and relatively safe. (As safe as handling gas is.....) Some dry Ice dumped into the tank is a great way to remove fumes (which are dangerous as hell). Dry ice "fumes" are heavier than gas fumes so the heavier will push out the lighter...
As a side note this is an extremely useful way of getting water out of a gas tank. Water and gas WILL NOT mix for long( as long as it's not being agitated) so the copper tube method can be used and will reach the lowest point or corner of the tank( where the water will be) and the water can be siphoned out with ease.
Some people pay lots of money to get a half gallon or so of water outa their tanks when they could've done this themselves....... :wink: