how to size Stilleto prop for my Suzuki

[sturgeonx]

I am looking to buy a stainless Stilleto prop for my DF115 and need some help. I am not sure what pitch to get, as I have heard they have a high rake and I never bought a stainless prop before.

My current boat and motor is a Suzuki DF115 on a Lund fishermain 18.5 ft. with 9.9 kicker on the back. Its heavy at the back and it blows out (ventilates) when I trim and turn.

I have currently 2 props for it.

A 14 x23 suzuki aluminum, At WOT it runs at 5400-5600 rpm's but it blows out when I trim or corner, my max speed is 40-42 mph.

the 14 x19 suzuki aluminum runs at 6100-6300 at WOT and my max speed is 38-40. and once alone it actually cut off the motor cause of the Rev limiter

The rpm range for this motor is 5000-6000. I would like to run it around 5900 at WOT.

Does anybody know which size I should get?

I was thinking of getting a 14 x20.

Will this prop help me with my hole shot and stop the blowing out (ventilating)?

Thanks

sturgeonx

 

[hwsiii]

Re: how to size Stilleto prop for my Suzuki

Sturgeon, i just need to know what year the Suzuki is.


H

 

[sturgeonx]

Re: how to size Stilleto prop for my Suzuki

Hi

Its a 2004 DF115.

Thanks for the help.

Sturgeonx

 

[hwsiii]

Re: how to size Stilleto prop for my Suzuki

I find you prop slip to be very good with both props at about 10%. But it is always better to have a motor and prop ombination that turns almost maximum RPM at WOT, so the 19" you have at this time is better than the 23" pith in my opinion. But without more information trying to deide whih make and model of prop is better for your uses is very hard to disern, if you will fill this form out I will be able to help more.

Prop Slip

Iboats Boat and Motor Info
1. Year, make and model of boat
2. Length, width and base weight of boat, look for boat decal on back of boat
2a.What is the maximum recommended HP for your boat
3. Number of people and gallons of gas normally on boat
4. What do you use the boat for
5. Is it a Deep Vee and if so how many degrees of deadrise
6. Year, make. manufacturer and model of motor
7. HP and gear ratio of motor IMPORTANT
If you don?t know the ratio, you need to pull the plugs out and put a piece of tape across the prop and the lower unit and then cut it between the prop and the housing and turn the motor until the tape lines up with each other, it is easier if two people do this, so one can watch the prop while the other counts the revolutions of the motor
8. Manufacturer?s recommended Wide Open Throttle (WOT) range
9. Anti-ventilation Plate height above keel of boat if it is an outboard in inches, use a board under the keel and stiking out to the anti ventilation plate for a referene
10. Is it a bass boat or does it have a pad bottom
11. Does it have a hydrafoil, dolefin or trim tabs
12. Make, model, diameter, pitch and whether SS or aluminum prop
13. WOT RPM and speed from your current prop and how much gas and how many people were in the boat for the test data and is the speed by GPS. Make sure you trim the prop up until it starts ventilating and then just trim in until it quits ventilating. If you do not have a tach you can buy a Tiny Tach for $ 50
14. Are you at sea level or a higher elevation, give us the elevation in feet
15. Has your motor been tuned up lately and have you checked that the carburetor butterfly is opening all the way, checked compression, and looked at the plugs and checked spark, all of the foregoing could be the reason your prop is not attaining full RPM
16. How long has this prop been on the boat and why, at this time, do you think it is the wrong prop
17. Does the prop show any damage that you can see
18. What problems are you trying to cure or what are you looking for the boat to do that it is not doing the way you think it should or to your expectations
19. If you are trying to attain a better cruising speed and fuel savings or trying to attain a faster speed I will want you to take your boat and run it with 1 or 2 people and give me the RPM and speed readings starting at 3,000 RPM in 500 RPM increments all the way to WOT.

REMEMBER, The numbers I give you will be NO better than the information you give me

The only thing I ask of you is to come back and give me a report of WOT RPM and speed for my database.


H

 

[sturgeonx]

Re: how to size Stilleto prop for my Suzuki

Here is the information I have on hand.

I will give you the info when I get a new prop and try it out.

Iboats Boat and Motor Info
1. Year, make and model of boat
2004, Lund fisherman 1800

2. Length, width and base weight of boat, look for boat decal on back of boat
Length= 18 ft, 6inches, 1475 lbs
2a.What is the maximum recommended HP for your boat
175 HP

3. Number of people and gallons of gas normally on boat
2people, 20-30 gallons
4. What do you use the boat for
Fishing, trolling sometimes cruising with the family,
5. Is it a Deep Vee and if so how many degrees of deadrise
It is a D vee aluminum, don?t know the deadrise
6. Year, make. manufacturer and model of motor
2004 Suzuki, DF115
7. HP and gear ratio of motor IMPORTANT
115 HP, 2.59 gear ratio

8. Manufacturer?s recommended Wide Open Throttle (WOT) range
5000-6000

9. Anti-ventilation Plate height above keel of boat if it is an outboard in inches, use a board under the keel and stiking out to the anti ventilation plate for a referene
-even
10. Is it a bass boat or does it have a pad bottom
no
11. Does it have a hydrafoil, dolefin or trim tabs
no
12. Make, model, diameter, pitch and whether SS or aluminum prop
Suzuki, 14 x23 aluminum
Suzuki 14x 19 aluminum
13. WOT RPM and speed from your current prop and how much gas and how many people were in the boat for the test data and is the speed by GPS. Make sure you trim the prop up until it starts ventilating and then just trim in until it quits ventilating. If you do not have a tach you can buy a Tiny Tach for $ 50
- Suzuki, 14 x23 aluminum- 5600 rpm 2 adults, 30 gallons GPS speed 41.8 mph
Suzuki 14 x19 aluminum, 630o rpms, 2 adults, 2 children( 15 lbs and 38lbs), 25 gallons, GPS speed 39.8 mph

14. Are you at sea level or a higher elevation, give us the elevation in feet
Sea leavel
15. Has your motor been tuned up lately and have you checked that the carburetor butterfly is opening all the way, checked compression, and looked at the plugs and checked spark, all of the foregoing could be the reason your prop is not attaining full RPM

Tune up at the beginning of year
16. How long has this prop been on the boat and why, at this time, do you think it is the wrong prop

Original when I bought this year, bought the 14 x19 to get better holeshot but It ventilates

17. Does the prop show any damage that you can see,
No

18. What problems are you trying to cure or what are you looking for the boat to do that it is not doing the way you think it should or to your expectations

Better holeshot, and better handling it ventilates a lot if I am not at full throttle and when I trim or try to turn. I am not trimmed up that high and it ventilates. If there are some waves its worst.
19. If you are trying to attain a better cruising speed and fuel savings or trying to attain a faster speed I will want you to take your boat and run it with 1 or 2 people and give me the RPM and speed readings starting at 3,000 RPM in 500 RPM increments all the way to WOT.

Don?t have the info as I am on vacation


thanks

 

[hwsiii]

Re: how to size Stilleto prop for my Suzuki

In my opinion it sounds like your motor is very high on the transom and that is what is ausing you to ventilate the prop in all of these situations, and you do not have the right blade geometry in your props to handle this height. I did notie you said it was even with the bottom of the boat, but when a motor is very high on the transom it auses the exat poblems you disuss when it doesn't have the right blade geometry to run that high. And believe it or not I show you are going a little faster than my preditions for your speed.

ould this be the problem, beause the right prop will ure that very easily. Without being able to see it I an't tell.

Antiventialtion Plate Height

H

 

[sturgeonx]

Re: how to size Stilleto prop for my Suzuki

Originally it was as low as it could go and it caused this problem also and there was alot of torque and it was hard to steer. It was a good 2 inches below the keel. I raised it to be even with the keel and I got less torque but it still does the same thing.

Here is a pictures of how it was when I originally bought the boat. Its on the top hole(lowest possible), I raised it to the 3rd hole from the top, now it is even.

It was ventilating at this height also.

 

[4JawChuck]

Re: how to size Stilleto prop for my Suzuki

Trim down when your turning, my 3 blade Laser II vents in a turn if its sharp unless I trim down...its common practice to trim down in a tight turn. I would run the 22 pitch unless you run with heavy loads/lots of passengers or pull skiers/tubes etc. where the 20 inch would be a better all around choice.

 

[hwsiii]

Re: how to size Stilleto prop for my Suzuki

Is that rivets or srews that I see on the bottom of the hull, beause if it is I would bet that you are having avitation from the bubbles formed on the hull from these protrusions stiking out and we an fix that just as well I believe fairly easily.



H

 

[sturgeonx]

Re: how to size Stilleto prop for my Suzuki

Is that rivets or srews that I see on the bottom of the hull, beause if it is I would bet that you are having avitation from the bubbles formed on the hull from these protrusions stiking out and we an fix that just as well I believe fairly easily.



H

they are rivets.

How would you fix the cavitation problems.

What prop would you recommend?

 

[hwsiii]

Re: how to size Stilleto prop for my Suzuki

If we add a 4th blade we will have more surfae area for the blades whih means that there theoretially will be less bubbles on any partiular area of the front of the blade whih means that there is less hane of having avitation begin. Also if it still gives us problems we an either chamfer the blades or add a little more cup to the trailing edge.
You need a Solas Amita 4 blade 19" pith prop from right here at Iboats and here are the numbers for it.


Price: $102.95
You Save: $44.05
Compare: $147.00
Discount: 30.0% Off
Add Amita Aluminum Propeller 3413-138-19 To Your Cart

Propeller Specifications:
SKU:#3413-138-19
Manufacturer: Solas
Brand: Amita
Material: Aluminum
Diameter: 13 - 3/4?
Pitch: 19?
Blades: 4
Rotation: Standard (Clockwise)
Usually Ships Within: 1 Business Day



H

 

[sturgeonx]

Re: how to size Stilleto prop for my Suzuki

If we add a 4th blade we will have more surfae area for the blades whih means that there theoretially will be less bubbles on any partiular area of the front of the blade whih means that there is less hane of having avitation begin. Also if it still gives us problems we an either chamfer the blades or add a little more cup to the trailing edge.
You need a Solas Amita 4 blade 19" pith prop from right here at Iboats and here are the numbers for it.


Price: $102.95
You Save: $44.05
Compare: $147.00
Discount: 30.0% Off
Add Amita Aluminum Propeller 3413-138-19 To Your Cart

Propeller Specifications:
SKU:#3413-138-19
Manufacturer: Solas
Brand: Amita
Material: Aluminum
Diameter: 13 - 3/4?
Pitch: 19?
Blades: 4
Rotation: Standard (Clockwise)
Usually Ships Within: 1 Business Day



H

Thanks

I am surprised you didn't recommend a Stainless prop.

I was leaninng towards buying a 3 blade prop stainless but know you completely threw a curveball.

I presume I will lose a bit of top end speed, will it handle better?

thanks

Denis

 

[hwsiii]

Re: how to size Stilleto prop for my Suzuki

You will likely lose a ouple of miles per hour, but if you want a stainless steel prop buy a Vensura 4 blade in 19" pith.

With either of these props you will find everything is muh better from hole shot to WOT and a muh smoother ride.

We just might have to tweak it to get rid of the last bubbles, but I think we will be fine.

If you deide on the vensura let me know beause i have a plae that will take are of you in ase of problems.
H

 

[sturgeonx]

Re: how to size Stilleto prop for my Suzuki

I think I am going to try the amita

If we need to work on it I am in canada so that might not be an option, but at the price Iboats has it I am willing to try it out.

Sturgeon

 

[hwsiii]

Re: how to size Stilleto prop for my Suzuki

I think that is a good hoie and I bet you are going to be very happy.


H

 

[hwsiii]

Re: how to size Stilleto prop for my Suzuki

Sturgeon, the guys at THT are not going to be muh help when talking about an aluminum prop, 80% of them are into higher speed boats.


H

 

[sturgeonx]

Re: how to size Stilleto prop for my Suzuki

I ordered the prop today, when I test it out I will give you the numbers.

Thanks again

 

[hwsiii]

Re: how to size Stilleto prop for my Suzuki

I will be waiting Sturgeon.


H

 

[sturgeonx]

Re: how to size Stilleto prop for my Suzuki

I received the prop and tried it out.

I am happy with the performance. It does not cavitate anymore and the holeshot is good but I am surprised with the RPm's at WOT.

Yesterday with 3 adults at WOT

37.8 MPH and 6300 rpms

today 2 adults

38.1 mph and 6400 RPMS the rev limiter was kicking in.

I thought for sure that the RPMS would be lower, closer to 6000 where I would like to have.

DO you think the 21'' pitch would bring me there?

I wish I had a dealer that exchange props...

Thanks for the help,

Sturgeonx

 

[hwsiii]

Re: how to size Stilleto prop for my Suzuki

We just might have to tweak it to get rid of the last bubbles, but I think we will be fine.

Ok, with our 4 blades we have cut way down on the cavitation, but we still are having a problem with too much excess air in the water at our prop. I am still showing too much prop slip, it stopped the cavitation but it didn't stop the ventilation. Bring the prop to a prop shop and ask them to put a 2" theoretical cup in the trailing edge of the prop. This will bring our RPM down and our speed up. I wasn't positive we would get clean enough water, sorry.


H