What is a good prop slip %

[floridaboy41]

I have a 17 ft. Saber flats boat with a 1993 Johnson 60 hp. with trim and tilt. Here is my numbers 5200rpm.,2.42 gear, 13/19 omc prop,gps speed 31.5 mph. The boat has a great hole shot but all the above shows a 19% slip. What do you all think. Is this good or should i go to a 13/17 prop. I need to stay with a alum. prop do to the many oyster bars.

 

[limitout]

Re: What is a good prop slip %

think you meant to say ss prop, aluminum and oysters don't play nice together lol.

 

[steelespike]

Re: What is a good prop slip %

Before making any change; is your speed by a gps? You may want to verify your tach is accurate.
Let me ask;Is It correct that on a flats boat the motor is set up high to help avoid contact with the bottom?
18% is a little high.Motor being high might increase slip.Operating near the bottom of the rpm range may increase slip. Even though you have good hole shot the 19 may be a little too much pitch which could also add to slip. I do think you should at least confirm your speed with a gps before a change.
A 17" prop of similar design should give amazing hole shot ,add about 400 rpm and may improve slip.
12% is a reasonable slip,of course slip depends on the weight and style of the boat.

 

[floridaboy41]

Re: What is a good prop slip %

As i said the speed was checked with a GPS. The tach. was also checked with another on and it to was correct. I like to run alum. props because losing a prop blade is better then bending a prop shaft. I have been there and done that and it can get costly. I plan to try a 13/17 and check things again.

 

[steelespike]

Re: What is a good prop slip %

I missed that, my bad.

 

[V153]

Re: What is a good prop slip %

I missed that, my bad.

In the future please try to pay closer attention ...

I think the OP'll be happier with a 17. 19's a lil tall for a 17' boat with a 60.

 

[steelespike]

Re: What is a good prop slip %

In the future please try to pay closer attention ...

I think the OP'll be happier with a 17. 19's a lil tall for a 17' boat with a 60.

agreed.

 

[floridaboy41]

Re: What is a good prop slip %

Thanks for the input. I will try the 13/17 when i get a chance to pick one up to try. I will post how that turns out. I did not know the weight of my boat but would say it would be close to the weight of a Carolina skiff with front and rear deck plus the small console . I would say less then 1200lbs. with full load.

 

[floridaboy41]

Re: What is a good prop slip %

I was able to find a 13 and 3/8 by 17 prop to try. This is what i got with this prop. 5400-5500 r.p.m. at 32 m.p.h. The engine has a 2.41 gear ratio. If i did the calculations wright it shows a 0.11 slip. The hole shot was good and i am happy with the speed.

 

[steelespike]

Re: What is a good prop slip %

seems like a good result.Isn't nice when a plan works.

 

[mpsyamaha]

Re: What is a good prop slip %

sounds like you found your prop!