F375 with Mercury 20hp EFI Prop Change

[Alan]

I have run speed checks over flat water the last 2 weekends and think I should upgrade from the prop that came with the motor. The boat had 5 gallons of fuel, the Bimini top in the stored position and a bow Cover.

Speed Check Results
2 adults 25mph
3 adults 25 mph
3 adults + 1 child 25mph

Based on the fact that the speed did not drop with the added loads i think I should consider a prop upgrade. Does this seam reasonable?

[ChrisParish]

Probably, but the only way to be sure is to get a tacho. If you are always getting to max revs then it’s time for a bigger pitch prop

[Alan]

Now I have a reason to add a tach. I was looking at the "Tiny Tach". others you think I might be better?