Think everyone got a little of course here ... the question was NOT for on water ... but on WET grass .
You have MORE than water to combat .
The wet grass blades act as a suction when they meet the hull which causes it to slow down . Now , if you were to achieve a speed fast enough to overcome this , then the next to battle is the actual grass itself . And the roughened bottome surface with then act like little pieces of sandpaper and again , slow it down .
The best thing I found is too change props for using from dry ground to wet grass .
You need to over come the "suction" of the wet grass when it meets the hull .
Think of sticking your foot in a mud pile . The suction is STRONG to overcome IF you are slow , but , IF your fast enough , the suction gets reduced as you increase speed .
Your best bet for a glassed hull , is leave it alone and change props for faster acceleration . If wood , then resin over the bottom .
The same prop that you use on water is NOT going to work best on wet grass .
( try it and you'll see - )