New Robalo R180 with Yamaha 115 FourStroke. Motor just turned over 10 hours, so I'm checking RPMs. With my self and wife in the boat, half a tank of fuel, WOT is 5600 and speed is 34 MPH. Later in the day, and with an additional person, WOT RPM drops to 5400, don't remember the speed, maybe 32. Operating range of this motor is 5000-6000 RPM. It also is a little anemic getting up on plane, but it is a heavy fiberglass boat, so that's not a serious issue at the moment and maybe a four blade prop to add lift to the stern is the answer there.
I'm not concerned about the top end speed as this is the wife's boat and it's a play boat for lake fishing, knee boarding, tubing etc. My concern is that I've run a lot and will be running quite bit in the lower RPM range and I don't want to dog the motor at the lower RPMs and I'm concerned that it may not be propped correctly for my intended use. Normal load is going to be 2-4 people. I understand it's hot weather and I'm going to pick up some RPMs as it gets cooler, but most of our play time is in hot weather. I can't find the paper that has the prop size and pitch on it, but that shouldn't be needed for a general question like this.
What say you Yammie gurus?
2015 Seaark 1872 MV CC Etec-90
Two Helix 12 CHIRP SI's, , MinnKota Riptide ST80/i-pilot Link, Bob's Hydraulic
2018 Robalo R180 CC, Yamaha 115
Bitter Gun Owner