# Prop Pitch Suggestions for 115 Mercury Optimax



## channa (Nov 17, 2007)

We have a 2009 Alumacraft Navigator Series 175 Sport with a 115 Mercury Optimax, and have a difficult time getting onto plane. Once we are on plane the boat runs just fine, it just seems to take a long time to get leveled out. I have had people suggest we get a different prop, but we are uncertain what pitch to get. Can anyone out there offer up a suggestion for this boat/motor configuration? 

thank you in advance for your opinions.

Channa


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## Misdirection (Jul 16, 2012)

Generally speaking the prop the manufacturer put on it is the correct one. Have you looked into a hydrofoil or trim tabs?

Sent from my DROID RAZR using Ohub Campfire mobile app


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## Bassbme (Mar 11, 2012)

You haven't given enough info to really make a suggestion. What are your RPMs reading as you run down the lake at wide open throttle? A person really needs to know that before they can make a suggestion. I know on my boat we went to a 4 blade prop and it increased the hole shot by leaps and bounds. The boat literally jumps up on plane. We had to go down in pitch because of the loss of RPM the extra blade caused, and lost a considerable amount of top end speed (7 mph) but the boat handles rock solid, where as it was pretty squirrely at speed prior to changing the prop. But you really need to post the prop you're running and the RPM at WOT before you can really be given any kind of solid advice. 

Also .... in looking up the specs for your engine I see the rpm range is 5,000 - 5750 so you'll need a prop that is going to keep you within that operating range. 

This is a link to a test that Mercury did for your exact boat. It shows speed, RPM at wide open throttle, fuel mileage etc. At the bottom of the page it tells what prop they ran on the boat. It shows them running a 13" diameter, 19" pitch aluminum prop.

http://www.mercurymarine.com/engines/engine-tests/boat-house-bulletin/?ID=481&


Addition: Also ..... don't take these questions as a slight of any sort .... just asking ..... I assume you're trimming the engine all the way down when you're starting out? And that you're letting it get up on plane and gaining some speed before you start trimming it up?


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