Rough guess on fuel range

Approximately how far do you think 3 gallons would take one 200 lb person with minimal gear in a 12 foot semi-v being pushed with a 6Hp outboard? So in other words, what is a reasonable guess on MPG or gallons per hour with this setup.

There is a formula for this I don't remember it all but I think at WOT a 6 hp motor will use .6 of a gallon per hour.

If you know the maximum fuel consumption of the engine in GPH, then, go with this figure to be conservative (always better to err on the side of caution when plotting fuel consumption in a boat)

Then, use a GPS to figure out the max speed of your boat in MPH with the given load.

Then, you calculate for the amount of fuel you have on board, as well as the max consumption in GPH. This will give you the total for cruise time at full load, or WOT.

Based on cruise time, and your vessel's max speed in MPH, you can then calculate its maximum cruise range at WOT.

Since a boat is typically run at 75-90% throttle, fuel consumption will be a little less than what you calculate, which is a good thing. But you want to calculate for WOT, to account for heavier loads, running against current or wind, attitude of bow, drag, etc.

And when plotting fuel consumption for a trip, always remember the 3/3 rule. 1/3 to get where you're going, 1/3 for the return, and 1/3 for reserve.

will the 6hp plane the 12ft boat out? Are you on a lake or river? I ran most of a 26 mile float on the buffalo with my 9.9 on less than 3 gallons of fuel.

Thanks for all the input guys.

I don’t know much about this setup yet, just trying to decide between a 3 or 6 gallon tank… looks like this guy had the same question:
https://www.tinboats.net/forum/viewtopic.php?f=4&t=15641

Using the rule of thumb of .6 GPH 3 gal would run 5 hours and the 6 gal about 10.

Guestimating speed at 10 mph from this thread.
https://www.tinboats.net/forum/viewtopic.php?f=21&t=22023

Approximate 3 gal range = 50 miles. Cut that in half for safety and error, gives 25… which sounds like plenty to me.