Prop Issues

[fourwinnsnate]

Alright so here is my dilemma my boat came with a 19P a 21P and a stainless 23P My boat is a very wide and deep 18.5 Fourwinns horizon with a volvo penta 5.7gli which i belive is about 255hp (2400lbs dry weight i believe) With the 19 i can plain at a reasonable speed (about 19mph) and my top speed is about 42mph but i hit rev limiter (4800rpm) at about 3/4 throttle no matter how many people i have in the boat.
Then the 21P will just touch rev limiter at WOT if there are two ppl in the boat at between 45 and 47mph but i can only plain pulling a wakeboarder at about 23mph which is quick when you are being pulled and it just feels wrong.
Then the stainless 23P must have only been used for cruising because i can only get about 4300rpm out of it at 48mph by myself but do 35mph at about 3500rpm no matter how many people in the boat but again only plain at about 23mph
Now i have ordered the smart tabs and am waiting on them for the slower plain but i know because i like wakeboarding i will still probably have to keep the 19 on for that... But by rights the boat should do over 50mph what is a good prop for this? i was thinking either a 19 or 21 high five??
Thanks

 

[hwsiii]

Re: Prop Issues

Nate, I an't imagine you need a High Five for that boat. I do believe you ould use an aluminum 4 blade for your purposes and have very minimal prop slip as well as exellent hole shot and a lower planing speed. But i think it would be a waste of money to purhase a High Five. If you will fill out this form I will try to help you.

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 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
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. 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

 

[fourwinnsnate]

Re: Prop Issues

I will fill out what i can now and give you the rest of the info on monday after taking the boat out for the weekend
Iboats Boat and Motor Info
1. Year, make and model of boat
1998 Fourwinns Horizon 185
2. Length, width and base weight of boat, look for boat decal on back of boat
Length 18.5' Width 8' base weight 2400lbs
2a.What is the recommended HP for your boat
Not sure
3. Number of people and gallons of gas normally on boat
4 People I keep it full so probably between 20 and 26 gallons
4. What do you use the boat for
Mostly watersports wakeboarding, skiing, tubing some cruising but i can always keep two props.
5. Is it a Deep Vee and if so how many degrees of deadrise
It is a Deep Vee what is deadrise?? and how do you measure it?
6. Year, make. manufacturer and model of motor
1998 Volvo Penta 5.7 GLi
7. HP and gear ratio of motor IMPORTANT
HP i believe is 255 i will have to get the gear ratio for you
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
4600-4700Rpm
9. Anti-ventilation Plate height above keel of boat if it is an outboard in inches
10. Is it a bass boat or does it have a pad bottom
Neither
11. Does it have a hydrafoil, dolefin or trim tabs
Hydrofoil on right now will take off when sx smart tabs come in
12. Make, model, diameter, pitch and whether SS or aluminum prop
Aluminum prop 1998 Volvo prop 19P
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. If you do not have a tach you can buy a Tiny Tach for $ 50
WOT RPM is bouncing rev limiter at 4800-4900rmp (which i hit at about 3/4 throttle) the speed is between 42 and 43mph GPS aprrox 13gallons of Gas and 2 people
14. Are you at sea level or a higher elevation, give us the elevation in feet
elevation is 1993Ft
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
Engine only has 200hrs haven't checked anything because performance isn't really an issue
16. How long has this prop been on the boat and why, at this time, do you think it is the wrong prop
The prop is always changing as i have 3 it is definitely the wrong prop for the boat should be able to just barely touch rev limiter at WOT not 3/4
17. Does the prop show any damage that you can see
Just paint missing blades, hub, splines and housing are all in perfect shape
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
Just want to plain at a lower speed and possibly get a little more top end out of her
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.
Will fill in on monday

 

[fourwinnsnate]

Re: Prop Issues

I will fill out what i can now and give you the rest of the info on monday after taking the boat out for the weekend
Iboats Boat and Motor Info
1. Year, make and model of boat
1998 Fourwinns Horizon 185
2. Length, width and base weight of boat, look for boat decal on back of boat
Length 18.5' Width 8' base weight 2400lbs
2a.What is the recommended HP for your boat
Not sure
3. Number of people and gallons of gas normally on boat
4 People I keep it full so probably between 20 and 26 gallons
4. What do you use the boat for
Mostly watersports wakeboarding, skiing, tubing some cruising but i can always keep two props.
5. Is it a Deep Vee and if so how many degrees of deadrise
It is a Deep Vee what is deadrise?? and how do you measure it?
6. Year, make. manufacturer and model of motor
1998 Volvo Penta 5.7 GLi 350 OMC engine which i believe is a GM
7. HP and gear ratio of motor IMPORTANT
HP i believe is 255 i will have to get the gear ratio for you
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
4600-4700Rpm
9. Anti-ventilation Plate height above keel of boat if it is an outboard in inches
10. Is it a bass boat or does it have a pad bottom
Neither
11. Does it have a hydrafoil, dolefin or trim tabs
Hydrofoil on right now will take off when sx smart tabs come in
12. Make, model, diameter, pitch and whether SS or aluminum prop
Aluminum prop 1998 Volvo prop 19P
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. If you do not have a tach you can buy a Tiny Tach for $ 50
WOT RPM is bouncing rev limiter at 4800-4900rmp (which i hit at about 3/4 throttle) the speed is between 42 and 43mph GPS aprrox 13gallons of Gas and 2 people
14. Are you at sea level or a higher elevation, give us the elevation in feet
elevation is 1993Ft
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
Engine only has 200hrs haven't checked anything because performance isn't really an issue
16. How long has this prop been on the boat and why, at this time, do you think it is the wrong prop
The prop is always changing as i have 3 it is definitely the wrong prop for the boat should be able to just barely touch rev limiter at WOT not 3/4
17. Does the prop show any damage that you can see
Just paint missing blades, hub, splines and housing are all in perfect shape
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
Just want to plain at a lower speed and possibly get a little more top end out of her
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.
Will fill in on monday

 

[hwsiii]

Re: Prop Issues

Nate, tell me what make, model, diameter, pith and material of the props you have. I also found that your motor has a WOT RPM 4,800 and a gear ratio of 1:43:1, please verify this.


H

 

[fourwinnsnate]

Re: Prop Issues

I will get the prop info for you tomorrow
The operating speeds were
3000 23mph
3500 29mph
4000 34mph
4500 37mph

The WOT and gear ratio are correct

 

[hwsiii]

Re: Prop Issues

Nate, it appears something is wrong, but there are a few things that ould ause your prop slip to be this high.

My ?c? is not working right now so please bear with me until my new keyboard gets here.

Prop Slip

1. I have the wrong gear ratio, please hek this
2. Your tahometer is not working orretly
3. You really have this muh prop slip

We just need to know whih one of the above problems we have to get a better prop for your boat.


H

 

[ramster]

Re: Prop Issues

Should be a 1.60 drive ratio for a V-8 Volvo SX, That boat with a 5.7 should be faster than that, I get 53 mph@4800 with my Glastron SX which is about the same weight and only a 5.0 carb. If it definatley is a 1.43 ratio, you would be looking at 18" four blade props.

 

[hwsiii]

Re: Prop Issues

Ram, if the gear ratio is even 1.6 his prop slip is still 27% at WOT. But isn't that SX a very different hull form than his Horizon. But if what I think is the problem then we definitely need a 4 blade stern lifter, I am just not sure whih pith yet.
WE need to take the boat out with a hand held tahometer and verify the RPM.


H

 

[fourwinnsnate]

Re: Prop Issues

Alright sorry about the bad info all the research i did suggested that the 1:43:1 gear ratio was correct i should have just done the test in the first place i was going out to do the test and i saw on the leg it says gear ratio 1.79 so that would be the ratio. Here are the specs on my props
Aluminum 14.5 X 19 not sure of the brand heres the number on the prop3850301
Aluminum 14.25 X 21 not sure of the brand heres the number on the prop3850302
Stainless 14.25 X 23 Turning Point Express

So The owner that had the boat before me said that he could get GPS 55mph out of the boat with the stainless 23 and i can only get 48 so theres a few options
A) the boat needs a tune up
B) he was lying
C) the 21.5" wide whale tail is affecting my top end
D) he was at sea level and i am well above it


As for the tach i am pretty sure its dead on because it hits rev limiter at about 4900 which is the factory rev limiter on this boat
Hope we can get to the bottom of this because i think that a 5.7 in a 18.5' boat should be able to do over 50 no matter what
O and i made a typo on the width the boat is 7' wide, not 8
The model of the boat is Horizon RXRS IO
The serial Number from the back of the boat is FWNMC077H798

 

[fourwinnsnate]

Re: Prop Issues

Alright sorry about the bad info all the research i did suggested that the 1:43:1 gear ratio was correct i should have just done the test in the first place i was going out to do the test and i saw on the leg it says gear ratio 1.79 so that would be the ratio. Here are the specs on my props
Aluminum 14.5 X 19 not sure of the brand heres the number on the prop3850301
Aluminum 14.25 X 21 not sure of the brand heres the number on the prop3850302
Stainless 14.25 X 23 Turning Point Express

So The owner that had the boat before me said that he could get GPS 55mph out of the boat with the stainless 23 and i can only get 48 so theres a few options
A) the boat needs a tune up
B) he was lying
C) the 21.5" wide whale tail is affecting my top end
D) he was at sea level and i am well above it


As for the tach i am pretty sure its dead on because it hits rev limiter at about 4900 which is the factory rev limiter on this boat
Hope we can get to the bottom of this because i think that a 5.7 in a 18.5' boat should easily be able to do over 50MPH
O and i made a typo on the width the boat is 7' wide, not 8
The model of the boat is Horizon RXRS IO
The serial Number from the back of the boat is FWNMC077H798
i doubt this will help much but just trying to get all the info i can for you

 

[fourwinnsnate]

Re: Prop Issues

oops didnt mean to put that in twice

 

[hwsiii]

Re: Prop Issues

LOL Nate, I am working on it. Whale tail is a nono for a boat like yours and elevation an maket ons of differene.


H

 

[fourwinnsnate]

Re: Prop Issues

Why is that?
and will the trim tabs be ok?

 

[hwsiii]

Re: Prop Issues

Trim tabs are perfet but whale tails an atually slow a boa down when you trim the motor up as it rates a lot of drag on some boats depending partially on how muh the motor trims up. I ould go into the problems of tripping but just know you an lose up to 5 MPH.

I need to know what elevation you are running the boat at beause that an make big differene as well.


H

 

[fourwinnsnate]

Re: Prop Issues

According to Google the elevation of where i live is 1993Ft which is where i do most of my boating

 

[hwsiii]

Re: Prop Issues

Nate I need to think about your prop overnite. Your answers to number 18 are usually mutually exlusive of eah other TOP SPEED and low PLANING SPEED.



H

 

[fourwinnsnate]

Re: Prop Issues

Yah i doubt that i will be able to get both out of one prop i have no problems running two props i just want to be able to plane at a low speed with one and i want to be able to do 55mph if i want to but my trim tabs came in so this weekend i will put them on and try the stainless 23 for top end

 

[hwsiii]

Re: Prop Issues

With those two hanges I expet you to get right next to your 55 MPH.


H

 

[fourwinnsnate]

Re: Prop Issues

Alright so this is a good cruising prop but i doubt i will be able to wakeboard with it even with the trim tabs.
So what is a good wakeboarding prop? I was thinking somewhere along the lines of a four blade 19 or 21