2001 Nitro 188 Fish & Ski setup

[Nitro_188]

Took the boat out yesterday and confirmed that the motor height is ok with the cavitation plate just out of the water when it's up on plane. I have a vented prop so I went ahead and 3d printed some plugs to plug the vents up before I ran it just to eliminate that as another factor. Boat had an additional passenger and would only do about 46mph, down about 4mph from normal. Not really sure what to do other than try a different prop, but the engine speed seems to be good around 5500rpm, so I don't see myself gaining much from that.

 

[Thomas Teller]

I recently purchased a 2001 Nitro 188 Sport so I could do some fishing with my son, and am starting to wonder if there is something off with the motor height or prop selection. The boat has a Mercury 150 XR6 that runs well, which the previous owner paired up with a Laser II 22P prop. The motor is mounted as low as possible on the transom's mounting bracket.

At WOT I am hitting 49-50mph at almost 6,000rpm when trimmed up with 2.5 people on board, empty livewells, and 1/2 tank of gas. From what I've read, this seems a little slow and my rpm seems too high for a 22P prop. This is my first outboard so I don't know much about setting them up, but am willing to take any measurements or provide whatever info is needed if someone could help me get this thing dialed in.

On a semi-related note, does anyone have a suggestion for a hydrofoil that will work well on this boat/motor? I would like to get the boat to stay on plane at the lowest speed possible so that it's easier to control when pulling kids on a tube.

Thanks!

Here's a sketch I found from a different forum on this site. It's very similar to one that I used to set up my re-power project to get it right.