RT188 Pro XS 2 Stroke Prop Suggestion

[bunz559]

So I've done some reading and searching through the various boards but I would like a little more insight and input. My boat is a 2014 with a 115 Pro Xs 2 stroke. It seems a lot of folks have some success with the more popular X7 and Laser 2 in a 20 pitch. Using the Mercury Prop Selector, a 19 pitch Laser and X7 are suggested. My numbers are as follow:

RPM: 5530
Speed: Averaging 43mph
Current pitch: 19

There is a bit of RPM to squeeze, but not much. I have no jack plate. Should I stick with a 19 pitch? Or drop to an 18?

[krr6581]

If you don't mind me asking what hole is your motor mounted in? Most of the guys who are running the X7 are mounted in the second hole. The X7 being a 4 blade really likes running higher in the water column. There are lots of guys with the 188 who are running this prop and their speeds are running higher around 47/48 mph.

[tcesni]

What sort of load are you carrying? 43 definitely is less than you should get from your rig.

[adb1228]

I'm running 41 with a 90hp. two guys and full tank of gas.

[GeauxTide]

I'm at hole #3. 19" X7 turns 5600@46mph. The 20" Laser turns 5600@48mph. The X7 is the superior prop.

[Bill Reynolds]

I am not very knowledgeable about the physics involved but I will share my experiences.
I had the same motor mounted on a 2014 hull that did not have the trim tabs. It was mounted on the transom in the second hole. I started with a 22 pitch LaserII but it was too much prop, I could only turn about 5200 RPM. at that, I was running 47-48.
I went to a 20 inch LaserII and got the RPM up to 5500 and speed went to 48-49.
I raised the motor to the third hole and could trim up and get the RPM over 5700 but the speed started dropping.
I had a porposing problem. I actually started with a 21 inch aluminum and could not trim over 1/4 With the 20 inch Laser, I could trim up to 1/2 so not only was the prop giving me more bow lift, it was holding it up.
In late 2015, my hull was replaced with one that has the welded trim tabs and I added the 4 inch setback plate. I am still running the 20 inch Laser, but my speed dropped to 45-46 and my RPM is about the same. The hole shot is great, mid range acceleration is great and I can trim all the way out without porposing. I am happy with this setup.
I still think my RPM should be higher, but not concerned enough to spend any more time or money on it.
One thing to watch for is where the wake starts when you are on plane, to get best performance, it needs to be at or behind the drivers seat.