Alum to S.S. for 115 E-Tec w/18' Wellcraft

[Black Snow Slide]

Going from aluminum to stainless steel prop. I put 280 hours on my motor last year and not even a little ding on it. I understand that people get better performance from stainless steal over aluminum.

My motor 07 E-Tec 115 hp. Prop on board is 13.75" diameter and a pitch of 17. It is aluminum.
RPMs at WOT with 1/2 fuel and 2 people is @ 4500. I am questioning the accuracy of my tach because when at 1/4 tank, minimal gear and myself motor at 5000 rpm sounds like it is screaming, and I always cut it back a little. I am going to have my dealer check tach for accuracy.

Assuming my tach is accurate, keeping my same diameter and pitch, and just changing to stainless steel what should is see for changes in performance?

What would changing to a 14" diameter with same pitch do? I have about 1.5" from top of blade to cavitation plate.

3 blade to 4 blade?

I know lots of questions but who better to ask?

 

[walleyehed]

Re: Alum to S.S. for 115 E-Tec w/18' Wellcraft

I'd darn sure get the tach figured out...
The 14" diameter prop will give a tad better hole-shot, but stay about the same on top-end unless you are going to lift the engine a hole or 2.
Do you know what the weight of the boat is?
Deep-V Right?

 

[Black Snow Slide]

Re: Alum to S.S. for 115 E-Tec w/18' Wellcraft

More on my boat 18' wellcraft bow rides sportsman. 20 degree dead rise, 2100lbs dry weight, motor 360lbs, 60 gallons of fuel is about 400lbs. (i have no idea what a gallon of gass weighs) With added about 400lbs of two people we are looking at a total weight of how i normally run my boat of 3400lbs.

 

[steelespike]

Re: Alum to S.S. for 115 E-Tec w/18' Wellcraft

More on my boat 18' wellcraft bow rides sportsman. 20 degree dead rise, 2100lbs dry weight, motor 360lbs, 60 gallons of fuel is about 400lbs. (i have no idea what a gallon of gass weighs) With added about 400lbs of two people we are looking at a total weight of how i normally run my boat of 3400lbs.

At 3,400 lbs + pretty serious deadrise it would seem to me your overpropped.Motor Developes its power at 5,000 I wouldn't be surprised to see you running at less than 5,000.
A brief look at 115 performance tests most are running 13.75 X 17 props
1,500 to 1,800 lb boats running 360lb motor 2 men 400lbs.+gas under 3,000lbs.total. Your about 500lbs heavier Than heaviest planing boat.