Proping confusion

[speedklz]

Ok.. I have read all the prop posts and I am still a little confused.. I am running a 20 foot Sylvan with 4 people on board and only half a tank of gas with a 4 stroke 03 Honda 75 horse.. prop is a solas D3 13.75x13 and WOT is 5K and 20 mph... Does this sound right or should this motor be turning in the 6K range on the rpm`s? and if it turns more rpm`s will I get more speed? or is this about right for a prop on this setup? More pitch? bigger/smaller prop??

[Bamaman]

You probably need to go to an 11 pitch prop. Your rpm's are a little low, and that may be as good as you can go.

[speedklz]

So what would be the issue.

[cwag911]

Running at 5000 rpm at WOT is lugging the engine.