Best prop for 17' Maxum?

[Suprathepeg]

I picked up my first boat an 88 maxum 1700 with 3.0 mercuiser. Weight with fluids is about 2000lbs. Alpha one has a hydrofoil on it.

My first time out I chewed up the 19p aluminum prop that came on the boat. On a concrete launch.

At the least I will need to repair my prop, so I'm wondering if I I should just replace it.

I want to be able to plane with 4-6 adults in the boat or pull a tube with 4 people in the boat. Looking to cruise at a good speed on the river and lake at a good Speed with the engine at its sweet spot.

I'm a newb so any help would be great!

 

[steelespike]

Check the cost here to replace the prop with something from iboats.
It may be cost effective to have it repaired.
Then do a lightly loaded wot test run minus the hydrofoil get us the max rpm and gps speed.
These numbers will help tell us about your setup.
A 19" prop is a reasonable start to evaluate your setup.
The motor needs to operate within its wot rpm rating.around 4400-4800 rpm.
You will need a working tach.and a gps.
Selecting a prop is like trying to select one gear in your car to do everything.
Higher numbers will have less power but more speed if the motor can spin it at the required rpm.
lower numbers delivers stronger power but less speed and may over rev.

 

[Suprathepeg]

So at WOT I am going average 33mph. I can rev it well beyond 4800 RPM and get on plane slowly bringing RPMs up to around 3k, below 3k it will start to fall off plane. I'd like to try a 21 pitch but I'm not sure if that is a good idea? I would like some more speed at cruising if possible but how much more can I expect to get?

 

[steelespike]

Are you running a new 19" prop? Is the speed by gps? Speeds at 4800+ would be about 40. I suspect your tach wrong.
How is the overall performance?Did you remove the Hydrofoil?Does the boat respond to up trim?

 

[Suprathepeg]

Prop was recently refurbished by a professional shop. Tach could be out but it definitely felt like it was revved up. Hydrofoil is still there and it responds to trimming up with about 2-3mph. Overall performance has been good, but I think I blew the gear case today....

 

[Suprathepeg]

No Title

Well it looks like the bottom end is ok, however this happened...

 

[Suprathepeg]

Prop venting with a 3.0 merc?

I have an older 3.0 merc in a 17' maxum. I was reading the literature that came with my new prop hub and it mentioned mercury's PVS. I'm chasing the best top speed for my boat and am wondering if anyone has run a vented prop on their 3.0L merc?

Experiences and prop specs would be sweet.

 

[Bondo]

Ayuh,..... You've got a 3.0l,..... Enjoy yer boat,.....

If ya wanta chase Speed,..... Ya need much Bigger power,.....

No disrespect intended,....

 

[Suprathepeg]

LOL I know I know. I was reading online a review where they used a 23P and got 50MPH but that was with a variable pitch.

 

[steelespike]

While there are some variables when trying to get the most out of any motor.
It's highly unlikely a 3.0 could push a 23" prop to 4800 rpm and if it did the speed wonld be about 46.
Shifting props can allow higher final pitch because it has a lower pitch for hole shot and shifts to the higher
pitch for wot.But the motor still has to operate within its rpm range usually 4400 to 4800 at 4800 23" makes about 46
and again the 3.0 isn't likely to twist a 23" up to 4800.

 

[Suprathepeg]

So how much effect does prop diameter have on things. For example my boat is currently running a measured 14"x19p prop. My father has a 13.5"x21p and a 13.5"x23p that I could try out. Is that difference in diameter going to make a huge difference?

 

[steelespike]

Diameter is seldom considered except for being sure it physically fits or for certain specific problems.
Speaking very generally as pitch goes up diameter goes down.
Nothing wrong trying either one of those props Won't hurt anything and will give you a good idea of the effect of pitch change.

 

[Suprathepeg]

This thread ise answering my questions: http://forums.iboats.com/forum/gene...rop-venting-with-the-3-0-merc?_=1439440872395