Prop size question
 

I have a friend who just bought a 2003 46 b.t. with 525s and xrs. What kind of speed should he run and what is the best prop for this boat? It has 26 merc 4 blades now and runs 70.5 mph.

Re: Prop size question
 

funny you should ask this question, I was just on the phone talking with my husband about props, we redid our engine over the winter and he was hoping for more speed which did not happen, he thinks if we are to see any more speed with our current engines we will need a different pitch, right now ours is a 4 blade with a 24 pitch. We are going to be testing a 22 pictch over the weekend. Currently we top at around 72 and I believe our engines are about 600-650 HP, but we only have a 43' so I would think for the 46 with 525's the speed is what you would expect, but heck I am no expert.
What does BT say, you could always PM Tim with Horseplay or Steve David, both know a lot about BT speeds plus they are nice guys and helpful.

BTW what is the pitch on your friends props

Re: Prop size question
 

Since you are not a big poster, I don't know if you knew they have a whole forum devoted to prop info. I was just checking it out and there is a wealth of info provided by some of the best in the prop business.

Re: Prop size question
 

We have 1.35 gears so our 24 pitch are about the same as 26-27 with 1.5 gears. 70.5 sounds pretty good for that boat. The pitch must be close. Maybe labbing would help.

Re: Prop size question
 

Thanks for the help..I own a cig. so I was little help for him. We have freinds who have B.T. but no 46 with 525.. He was running 1.51 gears and 26 then tried lab 28 and the boat could not handle them. So I guess lab 26 may be the ticket. Has you heard of anyone trying 5 blades?

Re: Prop size question
 

I'm close to making the decision to go to 5 blade props. SC430 with twin 750 EFI normally aspirated engines, Huber 1:1 trans, SSM 5 with 1.48:1 ratio, 4 blade 28 pitch 17" diam @ 5200-5400 RPM. 74-75 MPH on GPS full load of fuel, 7 people.

Re: Prop size question
 

how much do you think those props will cost you?? Ian thinks five blads would be nice but pricy. He is heading out this afternoon to try a differnt pitch on a four blade. We will let you know how that turns out.

Do you run your boat anywhere near Franklin or do you always travel to Lake Cumberland. Did I ever tell you Ian's sister and her son live in Franklin he graduated HS a few years ago from BGA, we went down for the graduation and it was beautiful but we did not see to much in the way of lakes

Re: Prop size question
 

Kevin,
That sounds right on the money. I was on the Miami Boat Show boat two years ago, 46s, twin 525EFIs, plenty of fuel and about 7 people, and we hit 71 in salt.

Re: Prop size question
 

Hi, your friends 46' is right on the money. This is assuming he's getting 5,200 RPM with a pretty full load of people and fuel. 5 blades will provide better mid range, but not necessarily top end on the 46'. They (5 blades) tend to have more stern lift, and you don't need that. Cost for the 5 blade, be it hydromotive or Merc will run you better than $1,100 per prop. If he does go to a 5 blade, he will need to drop 2 inches in pitch from the existing 4 blades he's running.

As to having them labbed, yes you might pick up a small increase in speed, less than 2 MPH, however you'll suffer a loss of life cycle on the props. If you hit anything, wood, etc. with a labbed prop you have a far greater chance of cracking a blade as opposed to bending a blade. A minor crack can turn into a thrown blade pretty quick, and that can result in some ugly damage to the lower unit or entire outdrive.

The boat Brian rode on in Miami had 4 blade 26's. We've tried different pitches on that particualr set up, and different prop types. The set up your friend currently has gave the best all around performance.

Hope he (and each of you) have alot of joyful hours in your boats!

Steve