Wookie:
Here's the formula for calculating MPG and range for a boat with a carburated, 2-stroke motor:
Maximum rated horsepower of the outboard (HP)
Times (x)
Ten percent (.10)
equals rate of fuel consumption in gallons per hour(GPH)
So, my boat's 150 h.p. carbed outboard will burn 15 gallons per hour (150 x .10 = 15) at Wide Open Throttle (WOT).
Then, using my boat's theoretical maximum speed at WOT (52 mph, GPS'sd) I can calculate MPG.
I'll burn 15 gallons in one hour and I'll go 52 miles. 52 divided by 15 equals 3.46 miles per gallon (woo-hoo, OPEC and my local BP-Amoco just LOVE me!).
My boat carries 41 gallons of fuel in its tank. So, if I run the whole tank dry at WOT, I have a theoretical range of 142 miles. But, for planning purposes, I hold ten-percent of my fuel in reserve for emergencies, so my practical range is 127.93 miles. That leaves me enough fuel to get to shore if I'm fighting a headwind or if I have to stop to rescue a stranded jet-skier (but only if she's wearing a bikini).
By the way, I'll be fly-fishing out of my boat this weekend. We use my TV-18 for bass, crappie and trout fishing and I may even try muskie fishing this year.
The TV's hull from the keel weld to the turn of the bilge is exactly the same as a Targa's. The height of the side walls is shorter on the TV-18, so the Targa's bow is partially the two side walls welded together. I do consider it a true deep-V because it doesn't flatten out at all in back, unlike a "pad" bass boat or a Pro-Team style Mod-v.
It will run in water as shallow as two feet with the skeg just brushing the bottom. If it's off plane, I can trim the outboard up so that the skeg is above the keel and then motor through water that is one or two feet deep (depending on how much gear and fuel is onboard and what/how much I've eaten in the last six months.) If I pull the trolling motor up so that ITS skeg is above the keel, you can go into whatever depth is sufficient to float the boat.
It's a great all-purpose fishing machine with a smooth ride in rough water without the weight of a fiberglass hull. And that's maxxed out at 150 h.p. I'd recommend that you consider a 115 on the TV-18, which will get you better fuel economy and package weight without sacrificing a lot of speed and performance. If you're going to use it in salt water, add extra annodes, flush the motor and wash the hull down thoroughly EVERY TIME you take the boat out.