Stepped down pitch, still no hole shot

[sharps45]

I have just purchased a 2000 23' Chris Craft 232 Deckboat, with the Volvo Penta sx, 250 hp, running three blade aluminum props. Most of my boating so far has been at high altitude (5000 and higher ft), but I am planning a trip to Lake Powell in two weeks, which is at 3600 ft. I tried my 19 pitch 14 3/4 at not quite WOT (breaking in new engine still) but still up to 3900 rpm to get to 34 mph. Can't get out of the hole with that prop, so I bought a 17 pitch 14 1/4 to try. At WOT rpm is 3600 and mph is 31, which seems about right, but it takes even longer to get out of the hole and onto plane. I tried all kinds of trim settings and still not getting what I want. Any skier would drown before getting out of the water.
I expected better hole performance from the 17 pitch. What is wrong?
I'm going to Powell and will be expected to pull skiers and boarders for the family. Please help!
Also, the nearest dealer wo would loan a prop is 100 miles away, so that isn't a real choice. thanks

 

[Texasmark]

Re: Stepped down pitch, still no hole shot

You dropped pitch, diameter, and rpm's at the same time. You'd expect rpm's to increase. So either you have gone from a high perf alum prop to a lower performance, or your boat has settled in the water, due to the lower speed. I'm going to say you have a mediocre 17P.

One thing that helps is porting the prop. Dhadley supplied a diagram to the site (archives) some time ago and shows what size hole to drill and where; one per blade. They really help hole shots.

Mark

 

[superpop]

Re: Stepped down pitch, still no hole shot

at 3900 RPMs max there is something wrong with your motor. Not the prop. You should be able to spin that motor up to 4500RPMs with the 17P prop on it. If you are saying your max RPM is 3900 then you need to have the motor checked as that is not a prop problem.

 

[Silvertip]

Re: Stepped down pitch, still no hole shot

Venting props on a four stroke is not generally advantageous.

 

[sharps45]

Re: Stepped down pitch, still no hole shot

I expected better performance than I am getting, so maybe getting the engine checked out should be my next step. Thanks for the input, and if anyone else has any thoughts, please share them. thanks again

 

[Dhadley]

Re: Stepped down pitch, still no hole shot

Did you test both props at the same altitude? Same conditions & load?

Are both props the same brand? What style / model props are they? (Obviously the 19 has much more diameter)

 

[Texasmark]

Re: Stepped down pitch, still no hole shot

Not hijacking the thread...one simple question, looking for one simple answer:

Silver, why not?

Just curious man.

Mark

 

[sharps45]

Re: Stepped down pitch, still no hole shot

Both props tested at same lake but different day. Conditions were the same. The 17 pitch is a Hustler, and the 19 is a Michigan. I thought both were quality props.
Looking around I found a 17 pitch with 15 inch diameter. Would the extra 3/4 inch dia. make a big difference?

 

[Jdeagro]

Re: Stepped down pitch, still no hole shot

Once again we are trying to find the right gear (PROP) to climb out of the "hole". What is wrong with getting rid of the "hole" so there is no up hill climbing, just level accelleration to plane?

Sorry guys it just makes me nuts! Your waisting time money and fuel.

 

[Dhadley]

Re: Stepped down pitch, still no hole shot

Hang in there John, he'll eventually get to the tabs. (BTW -- let's get together in Vegas)

Sharps45, yes - both props are OK but you're testing two different technologies. Got an apple & oranges thing going on. Obviously with an I/O you can't easily change the X dimension to get the best out of either prop. First, with a top rpm of only 3600 - 3900 the holeshot is indeed going to be bad. Are we sure the motor is operating properly? To get to the 4400-4600 rpm's you need we'd have to go way down in pitch and that doesn't seem right. Let's amke sure the motor is giving us it's all. Once the motor can get to full rpms then the next obvious step is to look into John's tabs. Holeshot won't be a problem with them and a good running motor.

 

[GlasstronJim]

Re: Stepped down pitch, still no hole shot

From my experience a 19 pitch mich. wheel and a 17 hustler that is cupped are pretty much the same prop.

 

[Jdeagro]

Re: Stepped down pitch, still no hole shot

Dale;

I know you are correct with regard to the RPMs. He is way off the mark.

In LV:
For sure! We should plan a dinner if you have some time.

Regards

John

 

[sharps45]

Re: Stepped down pitch, still no hole shot

So from the sound of things I could use some trim tabs. Any recommendations? I'm not super handy, so something easy to install would be great. As I mentioned, nearest shop is 100 miles away.
Also, the 3900 rpm with the 19 pitch prop was self-imposed. I am breaking in a new engine, and was told not to exceed 4000.
Hey, thanks for all the info, and if I don't answer right away it's because I'll be out of country for a week. Have a good week boating!

 

[Jdeagro]

Re: Stepped down pitch, still no hole shot

Search on this site, "Trim Tabs"

Also Marine Store on this site.