Engine RPM"s higher when boat is loaded with people = less top speed

[kielbasa]

Hi guys, wondering if this scenario is considered normal: I have a family style runabout (Seaswirl Spider), not a go fast boat, anyways, when the boat is loaded with only 2 people I can squeek about 49~50 speedometer reading. 53~5400 RPM's.
However, when the boat is loaded with 6 people, speedo reads 45~46 mph, but RPM's are 5500.
Normal or not? If not, what does it tell you?
If it matters, power is OMC GT150, Michigan Wheel Raptor 19" pitch, cavitation plate level with boat bottom.
Thanks for any input!!

[89LASER]

If it's a bow rider and people are riding in the bow, your center of gravity is different, you might be trying to trim it more and causing the prop to slip. I had a SeaSwirl Center console and it did the same thing. I put a 6" setback on it and got the prop into cleaner water making a night and day difference,

[kielbasa]

yup, people in the bow, however, trim was at neutral on both occasions (i played with trim, but found no difference in speedo reading).....

[91eagle]

I'm not an expert by any means and this is just a guess but it could be when your boat is full of people the props slipping more than when it's just two and that gives you more RPMs and less mph

[dgscroggs]

My mirage does the same with a big wheel on it when the family's in the boat my Rpms go up and the speed #'s go down I like to drop the motor a little to help carry the load or go to smaller wheel but either way the boats always gonna run faster by myself these are 2 different animals tho