Formula to calculate the effort needed to pull a weight on two wheels up an incline?

Assume no friction and incline surface is smooth. Knowing the % or degree of incline, how can one determine the pounds of force needed to hold or pull a given weight up a slope with the load on two wheels of known diameter? USE: letting a boat down a ramp to a lake, need for pulleys or winches, wheel stops, number of helpers, use of vehicle, or other aids. Searches in areas of education, science, Newton, physics, wheels, tools, inclines, levers and wheel sellers fails to find any response other than general dialogue without means to calculate this common activity.