Repowered need prop info

[NEEDABIGGER]

New to Forums , Boats and Props
First post. Can you please help.


1. Year, make and model of boat 1996 , Proline, Skif
2. Length, width and base weight of boat, 15' 4" - 68" - 780 Lbs
2a.What is the maximum recommended HP for your boat 75Hp
3. Number of people 2 and gallons of gas 6
4. What do you use the boat for Fishing Intercoastal (many no wake zones)
5. Is it a Deep Vee and if so how many degrees of deadrise Modified V
6. Year, make. manufacturer and model of motor 2000 , Honda , BF50
7. HP and gear ratio of motor IMPORTANT 50 Hp , 2.09:1
8. Manufacturer?s recommended (WOT) range 5,500 - 6,000
9. Anti-ventilation Plate height above keel. 1 hole up - 1" above
10. Is it a bass boat or does it have a pad bottom No Small V pad
11. Does it have a hydrafoil, dolefin or trim tabs Just installed smart tabs
12. Make, model, diameter, pitch, 3 blades Mercury Vengence 15p - 10 1/2 "
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 digital tachometer and hour meter here: http://cgi.ebay.com/ebaymotors/Tacho...Q5fAccessories $ 35
RPM 6100 Speed 32 GPS yes No. of people 2 Gal. Gas 6
14. At sea level
15. Has your motor been tuned up lately New factory power head with 12 hrs
Carburetor butterfly is opening all the way
16. How long has this prop been on the boat and why,
Prop came with the motor when I repowered.
The boat had a 50 Hp Force with a 14P prop and performed OK. No prop slip.
I did not have a tech or GPS at this time
Do you think it is the wrong prop Yes
17. Does the prop show any damage that you can see Looks New
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
Prop blows out when trying to get out of the hole. It also feels like it sliping at higher RPMs. The hub is OK.

Thank You
Needabigger Prop

 

[NEEDABIGGER]

Re: Repowered need prop info

I will try to post pics ?

Not sure if I did it correct. Newb.

 

[hwsiii]

Re: Repowered need prop info

Needabigger Prop, the pictures are excellent. I am a little bit lost on which prop you have the numbers for, I assume they are for the Honda, because the Force should have only turned about 5,250 RPM at WOT.

The Mercury Vengeance prop is their entry level SS and is not a really great prop. I ran some numbers on your prop slip and it is very high at about 23%, here are my numbers.

Prop Slip

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

http://forums.iboats.com/showthread.php?t=369057

If you will let me know if you are using the Vengeance 15" pitch on the Honda now I will make two recommendations for props, one in SS and the other in aluminum.



H

 

[steelespike]

Re: Repowered need prop info

You are in good hands.

 

[NEEDABIGGER]

Re: Repowered need prop info

Thank you for responding so quickly hwsiii. What a great site.
The vengeance prop is on the Honda. I am not looking for top speed, just
need to get out of the hole with out so much prop slip.

 

[hwsiii]

Re: Repowered need prop info

Needabigger Prop, in my opinion if you buy a Yamaha Black Painted Steel semi cleaver SS prop in a 15" pitch you will be very happy. In an aluminum prop I would recommend the Solas Amita Aluminum 4 blade prop, for about a $ 110 in the same 15" pitch you will also be very happy.



H

 

[NEEDABIGGER]

Re: Repowered need prop info

HWSII I did not take your advice now I am paying the price.
The yamaha prop was out of my price range and the local Solas delear talked
me into a reconditioned Power Tech prop.It is 13" pitch model SWC4.
10.75" DIAMETER, AVAILABLE IN 10"-15", 4 BLADES, RIGHT-HAND ROTATION, MORE GRIP AND CAVITATION RESISTANCE THAN SWC3, EXCELLENT FOR TUNNELS, MOTOR ELEVATION, AND CAVITATION-PRONE APPLICATIONS -
Hole shot, the prop takes 3-4 seconds to spin up to 3,500-4,000 and then it
shots out of the hole. Above 3,500 I can not make the prop slip no matter what I do. It does ventilate between 2,500 and 3,500. The motor is now mounted all the way up on the bottom holes.Ventilation plate 2" from the bottom of the boat. Top speed is 32 MPH @ 5,600 trimed out half way.If I
trim out any more I get a nice rooster tail, but no gain in MPH or RPM.
Over all I am happy with this prop but I would like to know if you think I am
lugging the motor ? Suggetions ?
Jack Plate ?
Remove some cup ?
New prop ?


Thank You NEEDABIGGER Wallet

 

[steelespike]

Re: Repowered need prop info

hwsiii should be along with some better informed thoughts.
According to the rpm specs your not lugging but if you usually run with a good load I think I would shoot for something closer to 6,000.Sometimes they remove a little cup with excellent results. Your allready working with a reworked prop I'd worry about the venting if you started to fiddle.When you said the plate was 2 inches from the bottom did you mean above?

 

[NEEDABIGGER]

Re: Repowered need prop info

Thank you for taking the time to respond STEELSPIKE
The ventilation plate is 2"+ above the bottom.
I hope that HWSII has a solution.