Generally speaking thrust will not increase with more pitch at a given RPM at a given diameter propeller. Since RPM drops with more pitch, more pitch will achieve less thrust when the propeller diameter remains constant. A larger diameter propeller with less pitch will generate more thrust.

Using this STATIC THRUST CALCULATOR we get the following:

A 14 X 8 propeller will turn about 10,000 RPM @ 2 HP & generate about 10 1/2# of thrust, a similar 15 X 6 will turn similar RPM @ the same HP yet generate nearly 14# of thrust.