whats the best prop for speed for a alpha 1 with a 305

[huntingdeer]

Im trying to get speed.I dont tow or pull tubes.Its a fishing boat that only carries 4 people.Its on a 19 foot ski boat.

 

[huntingdeer]

Re: whats the best prop for speed for a alpha 1 with a 305

it has a 4b-b32634-cl-23.what is that for tubing or?

 

[QC]

Re: whats the best prop for speed for a alpha 1 with a 305

Here's how we can help here. We have to go through this or no one can answer this question. I am guessing that is a 23 inch pitch, but that part number is not working for me so far.

1) Read this stickie at the top of the prop section

2) We must have your current prop's dimensions (# of blades, diameter and pitch). Maybe we get that from above, but not working so far.

3) We must have the current, accurate, RPM at wide open throttle. Should be a typical load, gear, people etc. Trimmed out as fast as she will go.

Without this information we can't really get you to where you want to be. There are no "standard" props per se. All are specifically matched to your combination of power, boat and load. What may work for one guy, may not for you in very similar boats, etc. First thing for sure is read up on this stuff at the top of the section. Good luck!

 

[jestor68]

Re: whats the best prop for speed for a alpha 1 with a 305

Im trying to get speed.I dont tow or pull tubes.Its a fishing boat that only carries 4 people.Its on a 19 foot ski boat.

Usually, a "fishing boat" and a "ski boat" are two different things. A better description of the boat; year,make,model,etc. will help.

Generally, a 4 blade prop might be considered better for water sports activities; while a 3 blade prop usually provides superior top speed. An a SS prop almost always out performs an aluminum prop.

So, for best top speed, a SS 3blade prop will usually work best on your average runabout(if that's what you have).

In order to recommend the best prop, we'll need the precise current performance numbers of your current set up.

 

[huntingdeer]

Re: whats the best prop for speed for a alpha 1 with a 305

Usually, a "fishing boat" and a "ski boat" are two different things. A better description of the boat; year,make,model,etc. will help.

Generally, a 4 blade prop might be considered better for water sports activities; while a 3 blade prop usually provides superior top speed. An a SS prop almost always out performs an aluminum prop.

So, for best top speed, a SS 3blade prop will usually work best on your average runabout(if that's what you have).

In order to recommend the best prop, we'll need the precise current performance numbers of your current set up.

Its a 89 19 foot phantom ski boat.It was a ski boat but i got it on a good deal and removed all the frount seats and made a deck.Thats why i said fishing boat.I am not sure of pitch.I gave you what the blade said.i dont know much about speeds yet i just got it.

 

[huntingdeer]

Re: whats the best prop for speed for a alpha 1 with a 305

its a 3 blade btw.on cl the l may be a 1.

 

[jestor68]

Re: whats the best prop for speed for a alpha 1 with a 305

Usually the last number(-23) indicates the pitch number of the prop; in this case it indicates a 23 pitch prop.

The important thing to know is what rpm does the motor turn up with the current prop, and go from there. Given that your 305 is rated to turn 4400-4800(?) rpm(you haven't said what year it is) you adjust your prop size based on what it does with the current prop, using the tried and true formula of 150-200 rpm change per inch of pitch.

 

[H20Rat]

Re: whats the best prop for speed for a alpha 1 with a 305

Its a 89 19 foot phantom ski boat.It was a ski boat

Just to avoid confusing anyone, that isn't a ski boat, its a typical bowrider setup. Ski boats have direct drive inboards, with the engine mounted midship. BIG difference in props!

At least according to google, something similar to this.

 

[huntingdeer]

Re: whats the best prop for speed for a alpha 1 with a 305

Just to avoid confusing anyone, that isn't a ski boat, its a typical bowrider setup. Ski boats have direct drive inboards, with the engine mounted midship. BIG difference in props!

At least according to google, something similar to this.

View attachment 199016

somewhat but with seats in the front. It is a 89 mercruiser.