what prop do i need

[proline23]

I have a 1993 proline 230 walkaround(23ft) with a 1993 yamaha 200hp 2stroke,holds 100 gallons of gas and usually 4 people, engine is mounted on an engine bracket. I want to know what the recomminded max rpm is and what kind of prop i need (3 or 4 blade) and size and pitch. My current prop is a 3 blade stainless, it has 19-m stamped on the it i assume it means a 19 deg pitch. WOT with this prop is 4800-5000. I have to trim it down on turns and have to keep the throttle up to maintain plane. My top speed on my fish finder is around 35-40mph.

 

[steelespike]

Re: what prop do i need

Welcome
Pitch is measured in inches.If you read the stickies at the top of the page it will help you understand props better.Your hp is rated at 5,500 so you should be at at least close 5,500 with a typical load. It would be nice to see your speed by gps.Assumingb the boat, motor and prop are in excellent tune;Rule of thumb dropping 2" in pitch to a 17 will add "about" 400 rpm. A 4 blade prop should improve hole shot,and stay on plane better usually recommended to drop 1" pitch when going to a 4 blade.Putting you at a 16"You should try to stick with the same brand and material.You should wait for more input before making any changes.

 

[Dhadley]

Re: what prop do i need

You might also look at the set up. Pro Line is well known for mounting motors too low. If so, get the motor set up right and retest with your current prop before spending $$$ on a new prop. If it is too low, raising it will help not only the top rpm but the overall performance too.

This is assuming the current prop is in good shape of course.

 

[proline23]

Re: what prop do i need

Thanks for the replies, I bought the boat about 2 months ago. It is in great condition with low hours. The prop is in good cond. with no chips or scrapes. what is the optimum depth for my engine and where should i measure it from. At WOT the waterline on the engine is where the bolts for the lower unit bolts to the engine.

 

[steelespike]

Re: what prop do i need

Being on a bracket its difficult to measure. Raise it a hole at a time to a point just before venting(cavitation) becomes a problem.If your allready having to trim down to turn you may not be able to raise it. A 4 blade prop will usually allow more height.

 

[Dhadley]

Re: what prop do i need

Figuring the height is no big deal. For every 5-6" the motor is back from the transom it can go up 1". That's a very general rule of thumb. Props with more technology can run higher. A couple of manufacturers use "M" as a designiation but generally aren't a prop with a lot of technology.

 

[proline23]

Re: what prop do i need

I have been researching props and still have a lot to learn but i think i like the Michigan wheel apollo prop.They also have the ballistic model. I am mostly interested in top speed,staying on plane and fuel mileage not so much hole shots. Would a 4 blade still be the best option or 3 and do i need to stay with the same diameter.
Also i heard michigan wheel filled for bankruptcy are they still a good brand and is there a beter brand some one can recommend for my set up.

 

[proline23]

Re: what prop do i need

Should i stay with the same diameter prop?

 

[hwsiii]

Re: what prop do i need

Proline, in my opinion Spike and Dale are both giving you good advice. There is nothing wrong with Michigan props financially at this time, they have been bought and are in good shape.
But like Dale says you need to move the motor up at least one more hole on your bracket, as this will increase your RPM and speed. You will probably gain another couple hundred RPM, but you will tend to ventilate worse in turns because of the prop you are using. My preliminary data shows you have a prop slip of about 20% and are using the wrong prop for your setup.
The numbers you gave for RPM and speed are not good enough to be able to tell how much real prop slip you have as they are just too wide a range. You need to use a GPS for speed and you need to know the exact RPM you are turning.

You also might try reading this for a better understanding of changing props for better performance, and the second one for what are the major differences between aluminum props and stainless steel are.

http://forums.iboats.com/showthread.php?t=366160

http://forums.iboats.com/showthread.php?t=365653

If you would like my help fill this form out and I will help you as much as humanly possible, if you would prefer to not go to this much trouble there are other people who will gladly help you. My expectations are that you are willing to expend as much time and energy as I will to find a better prop for your boat.

Just copy this form to your computer and paste it into a word processing program and fill it out, then paste it into your post.

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, manufacturer and model of motor

7. HP and gear ratio of outdrive IMPORTANT
If you don?t know the gear ratio, you need to pull the plugs out of the motor and put a piece of tape across the prop and the lower unit and then cut it between the prop and the housing then do the same thing on the flywheel and turn the motor until the tape lines up with each other on the prop, 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 the bottom of the transom of boat if it is an outboard in inches, use a straight edge or a board under the keel and sticking out to the anti ventilation plate for a reference, and take about 4 pictures for us to see.

10. Is it a bass boat or does it have a pad bottom

11. Does it have a hydrafoil, dolefin, whale tail or trim tabs

12. Manufacturer, model, diameter, pitch, number of blades and whether SS or aluminum props.
IMPORTANT
1.
2.
3.

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 less than $ 50
RPM ___________ Speed (GPS)___________ No. of people ____________ Gal. Gas ________

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 by only using the control on the console, checked compression, looked at the plugs and checked spark, is the bottom of the boat clean and barnacle free, and have you checked the Tachometer against a mechanics tach, 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.
1. 3000 RPM
2. 3500 RPM
3. 4000 RPM
4. 4500 RPM
5. 5000 RPM
6. 5500 RPM
7. 6000 RPM

REMEMBER, The prop I recommend 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

 

[proline23]

Re: what prop do i need

Iboats Boat and Motor Info

1. Year, make and model of boat
1993 Proline 230

2. Length, width and base weight of boat, look for boat decal on back of boat
23.5 L/ 8ft.W- Decal says: 2500lbs. person motor & gear- 9 person or 1200lbs.

2a.What is the maximum recommended HP for your boat
270Hp

3. Number of people and gallons of gas normally on boat
4 People 100gal.

4. What do you use the boat for
Off shore fishing/crusing

5. Is it a Deep Vee and if so how many degrees of Deadrise
Deep Vee; don?t know how to figure deadrise.


6. Year, manufacturer and model of motor
1993 Yamaha 200 TXRR

7. HP and gear ratio of outdrive IMPORTANT
If you don?t know the gear ratio, you need to pull the plugs out of the motor and put a piece of tape across the prop and the lower unit and then cut it between the prop and the housing then do the same thing on the flywheel and turn the motor until the tape lines up with each other on the prop, it is easier if two people do this, so one can watch the prop while the other counts the revolutions of the motor
Flywheel 1 7/8- Prop 1

8. Manufacturer?s recommended Wide Open Throttle (WOT) range
I think 5,500 RPM

9. Anti-ventilation Plate height above the bottom of the transom of boat if it is an outboard in inches, use a straight edge or a board under the keel and sticking out to the anti ventilation plate for a reference, and take about 4 pictures for us to see.
35? out from transom - 4 ? inches down from ventilation plate
Judging by the rule of thumb, I think my engine should be raised 2-3 inches








10. Is it a bass boat or does it have a pad bottom
No

11. Does it have a hydrafoil, dolefin, whale tail or trim tabs
No

12. Manufacturer, model, diameter, pitch, number of blades and whether SS or aluminum props.
Manufacturer ?; Model ?; Diameter14?; Pitch ?; Number of Blades 3; Stainless Steal
This is the only numbers I could find on the prop (19-M)

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 less than $ 50
RPM 5,500 Speed (GPS) 41MPH No. of people 3 (515 lbs of people) Gal. Gas 100

14. Are you at sea level or a higher elevation, give us the elevation in feet
Sea level

15. Has your motor been tuned up lately and have you checked that the carburetor butterfly is opening all the way by only using the control on the console, checked compression, looked at the plugs and checked spark, is the bottom of the boat clean and barnacle free, and have you checked the Tachometer against a mechanics tach, all of the foregoing could be the reason your prop is not attaining full RPM.
Yes, runs great; has new plugs; carbs just rebuilt; trailor boat (no barnacles)

16. How long has this prop been on the boat and why, at this time, do you think it is the wrong prop.
I think it is the original prop; I have only had the boat for 7 months. It seems to be sluggish; ventilates on turns and takes a long time to plain out; and slips.

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
Less ventilating; Higher top speed if possible; better grip; faster plaining

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.

3 People: 5 People:
1. 3000 RPM: 15 14
2. 3500 RPM: 25 20
3. 4000 RPM: 31 26
4. 4500 RPM: 36 31
5. 5000 RPM: 40 36
6. 5500 RPM: 41

*******p.s. If there are any questions,need any more info or can help me get any beter info for you please let me know. Thanks

 

[hwsiii]

Re: what prop do i need

Proline23,

9. Anti-ventilation Plate height above the bottom of the transom of boat if it is an outboard in inches, use a straight edge or a board under the keel and sticking out to the anti ventilation plate for a reference, and take about 4 pictures for us to see.
35? out from transom - 4 ? inches down from ventilation plate
Judging by the rule of thumb, I think my engine should be raised 2-3 inches

You might be able move it up one more notch after changing to a prop with better blade geometry, but let's see how we do with a prop change first.

16. How long has this prop been on the boat and why, at this time, do you think it is the wrong prop.
I think it is the original prop; I have only had the boat for 7 months. It seems to be sluggish; ventilates on turns and takes a long time to plain out; and slips.

You need a prop with better blade geometry and more blade surface area to carry the drag that your boat produces, and right now your prop is not good enough for the height your motor is set at, that is why it ventilates. And the reason it takes so long to plane and has so much prop slip is because it is the wrong prop for your setup.

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
Less ventilating; Higher top speed if possible; better grip; faster plaining

A Solas Amita or Rubex 4 blade aluminum prop in a 19" pitch will be perfect for your present setup you can buy it cheap here at Iboats.. I expect you to gain about 4 MPH with the new prop, as well as your time to plane will be much quicker as well as your acceleration from one RPM to a higher RPM. I got all of this information from my analysis of you present prop and its performance with your setup.

Prop Slip

H

 

[proline23]

Re: what prop do i need

Thanks for the quick reply. I have always heard that stainless steel props are beter than aluminum. Is this true? Is there a reason you recaminded an aluminum prop. Also do i keep the same diamier if i stay with your recammindation but go with ss.
Thanks

 

[proline23]

Re: what prop do i need

should i stay with the recamminded 19"pitch or a 17". Also i would much rather have a ss prop. should i change any other numbers if i go with a ss 4 blade.