There have been a thousand threads about trailer tongue weight, but I have never seen this question.
Is there some magic formula to calculate how far forward (or back) a boat would need to be moved to change the weight on the tongue?
I have a 31 Formula that weighs 8,000# empty, 130 gal. fuel, 1500# aluminum 3x trailer. I need approx 1,000 lbs of tongue weight, but just measured and only have about 275!!!!
I'm guessng I need to come forward about 10 inches, but any suggestions?

Too many variables IMO. All trailers are different, and all boats are built different. What would work on one wouldn't work on another.

It's going to be trial and error. I say try a couple inches at a time. You would be surprised how much difference a couple inches can make on your tongue weight. (not to mention a a few other things)

You are on the right track for the amount of weight you are looking for though.

Buck

First of all, you want a trailer that is level when loaded and hooked up to the hitch along with a 5-10 % tongue weight ratio. For instance you're saying with approx. 812 lbs of gas; 8000 lb boat; 1500 lb trailer you've got a total of approx. 10,312 lbs. Using roughly 10% tongue weight (0.07 x 10312) you should end up in the ballpark of 721 lbs. Then be sure you have a level trailer so that all the weight is evenly distributed over all three axles so that one axle isn't taking all the punishment and either fails, or blows a tire. Be sure you have the right slider with the proper drop distance to keep it all level.

you say 10% but then use 7% for your calc???????

It's that Virginia math....hey how come I know what he's talking about???

i thought that was west virginia math...