Is my motor to low or is my prop just wrong?

grizzrider09

Seaman
Joined
Jun 20, 2012
Messages
54
Let me give you guys some history. I bought a brand new boat in 2013. Its a Crestliner Vt 17. It came with a 60hp 4stroke merc that had a 13p vengance stainless prop on it. The boat had an awful hole shot right from the start. I called the dealer and they told me that it was just how it was going to be with a 4 stroke engine. The boat would run around 34 mph. I decided to buy a fin to go on it and see if that would help and it did. I kept it that way until a few months ago. I have a friend who has a tracker boat with the same engine and he is running a 4 blade spitfire and loves it. The boat comes up on plane great and will run about 36. So I bought a 12p for my boat. I took the fin off and ran it. Top speed was 30 mph at 6100 rpm. I decided rpms were to high and bought a 14p 4 blade. Top speed was 32 mph and rpms were 5300. So then I swapped out with my friend like I should have done to start with and put his 13p 4 blade spitfire on my boat. Top speed is 31 with 5900 rpms. I'm ok with that but the boat is porpoising really bad with two people in it and there is a ton of spray with all of these props except the 12p. It looks to me like the motor is just buried in the water when its running but that may just be the way it should be. Do you guys think I'm just running the wrong prop or could my motor be mounted to low?
 

Sea Rider

Supreme Mariner
Joined
Sep 20, 2008
Messages
12,345
4 blade 12 pitch seems fine if will be boating frequently with 2 up, OB is just revving 100 less wot rpm if 6 K is the max. Is the rear water spry out transom or at middle OB/transom ? That's an indication that OB sits too low, is that a clamp OB or has holes on swivel bracket to adjust height ? Two different boats with same OB can't be performance compared between them, each is unique, needs its own prop/pitch.

Can you post a lower leg pic shot sideways while OB is mounted on transom ?

Happy Boating
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
Staff member
Joined
Jul 23, 2011
Messages
47,296
when you post the pic, step back about 6' from where you think we want the shot. we want to see the side of the boat, transom and motor
 

grizzrider09

Seaman
Joined
Jun 20, 2012
Messages
54
I will see if I can get a pic this afternoon. the ob bracket has holes to allow for moving up and down. The spray starts right about where I sit which is about 4ft in front of the outboard.
 

Sea Rider

Supreme Mariner
Joined
Sep 20, 2008
Messages
12,345
Water splashes at both sides of rear hull as indicated is normal, all boats do that at speed. Rear transom lower leg splashes is other story..

Happy Boating
 
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