Propeller assistance

[StefanMostert]

Good day all.

I have a Johnson 115 engine with a 14 x 17 propeller on. I do a lot of water skiing and the propeller is suitable for that purpose. I recently learned how to slalom on a friend's boat and when I moved to my boat I realized that the boat does not have the sufficient power to get me out of the water properly. I do get out of the water but it requires a lot of effort.

Now, my first question is, how big of a difference will the 13 4/3' x 15 propeller have?
And my second question is, I don't really want to loose a lot of km/h. My top speed at the moment is around 55km/h will this come down a lot?

I hope to hear from you soon.

Thank you

 

[alldodge]

Would need to know what is your WOT RPM now?

Going into skiing requires more hole shot, and in most cases it requires 2 props to take full advantage. One for fun and one for ski

 

[StefanMostert]

It is about 5100RPM

 

[alldodge]

Not sure what max rpm should be but thinking it would be around 5500, then you will probably over rev by a few hundred when not skiing. Might loose a few KPH

Finding the V4 gear case is 2.0 and the V6 is 1.86 or 2.20 ratio

 

[racerone]

What boat?----What model # of your engine?-----Check condition of engine.-----If it is a crossflow you need to do a compression test.----Post your numbers.----And I doubt that your top speed will change by going to a 15" pitch.-----Again I doubt that top speed will change.------Propellers and boat behaviour are much mis-understood I say.

 

[Scott06]

I would consider a four blade. Like you i used to run a 17” three blade black max prop for skiing. Swapped in a 4 blade 16” michigan vortex ade a big difference in hole shot and pulling up slalom skiers with an under powered 3.0/135 hp/18 ft boat. Ultimately is it as good as a bigger engine, no but excellent bang for the buck. You may loose 3 or so mph top end. I used this prop for skiing, and an 18” 4 blade for tubing and cruising

 

[ahicks]

Like many other things, props are about compromise. I like the 4 blade idea, but to do that right for your ski application, you're going to really affect your top speed. Decide which you'd rather have or get a bigger motor.....

 

[Texasmark]

You have boat or engine problems. I easily slalomed at 250# behind an 18' Caravelle bow rider running as high as 35 MPH at times (ouch when I fell off) with wife driving plus 4 kids and gear powered by an engine rated 125 Johnson (1972) with a 13+17P SST prop with only a tilt bracket....no PTT in 1972 on that engine, tilt yes but not PTT....came out in 1973.

 

[racerone]

Agreed-----In my younger days friends had a 1966 model 100 HP Johnson on a 17' deep V hull.-----Would pull 2 of us ( 25 years old ) up out of the water on slalom skis.----So check your motor condition and check your boat.

 

[ahicks]

You have boat or engine problems. I easily slalomed at 250# behind an 18' Caravelle bow rider running as high as 35 MPH at times (ouch when I fell off) with wife driving plus 4 kids and gear powered by an engine rated 125 Johnson (1972) with a 13+17P SST prop with only a tilt bracket....no PTT in 1972 on that engine, tilt yes but not PTT....came out in 1973.

I was that size and used to do a lot of slalom sking a hundred years ago. I'm left with 2 thoughts here (other than there were no 4 blade props available then). Clearly there could be some differences in the motor state of tune, the hull shape and weight, AND the skill of the skier. A rookie slalom skier can take a LOT of grunt to get out of the water, especially one that size.....

 

[Texasmark]

You have boat or engine problems. I easily slalomed at 250# behind an 18' Caravelle bow rider running as high as 35 MPH at times (ouch when I fell off) with wife driving plus 4 kids and gear powered by an engine rated 125 Johnson (1972) with a 13+17P SST prop with only a tilt bracket....no PTT in 1972 on that engine, tilt yes but not PTT....came out in 1973.

I was that size and used to do a lot of slalom sking a hundred years ago. I'm left with 2 thoughts here (other than there were no 4 blade props available then). Clearly there could be some differences in the motor state of tune, the hull shape and weight, AND the skill of the skier. A rookie slalom skier can take a LOT of grunt to get out of the water, especially one that size.....

Well having some whoopie in front of you helps. I remember the difference in my abilities the first time I got behind something that could pull. I learned to ski (on 2) behind my 14' wooden boat with an 18 Evinrude Fastwin...friend and I taking turns driving. I was about 15 and used mama's car as I didn't have one....but I had a boat!

We were skiing in Taylor Lake which feeds into Clear Lake, the location of the Houston NASA facility. Lake was only 3-4' deep (depending on tide) and 1' of mud for a bottom. Never wore a life preserver as if you fell off, you just got up.....hopefully not landing head first and getting your head stuck in the mud. Grin!

Later on, with decent HP tugging on you it was a lot easier maintaining control and getting up fast. On Slaloms, I found that the doubler handle ski rope went a long way in starting out and maintaining an even pull to help you learn how to keep things lined up and keep your balance.

I'll agree, just like anything else, experience in getting it right goes a long way toward success.

 

[Sea Rider]

For top skiing you only need to count with the skiier, a driver and spotter if in need to count with one while the motor revs well propped towards its max wot rpm range factory stated to achieve an oustanding hole shot, all other boating members must stay at terra firme sipping cold drinks. Will be excellent to count with 2 dedicated props, one for skiing, the other for family recreational purposes.

Happy Boating​

 

[racerone]

We used to go with 4 or 5 people for these adventures and no problems for that 100 HP of the day !!

 

[ahicks]

Well having some whoopie in front of you helps. I remember the difference in my abilities the first time I got behind something that could pull. I learned to ski (on 2) behind my 14' wooden boat with an 18 Evinrude Fastwin...friend and I taking turns driving. I was about 15 and used mama's car as I didn't have one....but I had a boat!

We were skiing in Taylor Lake which feeds into Clear Lake, the location of the Houston NASA facility. Lake was only 3-4' deep (depending on tide) and 1' of mud for a bottom. Never wore a life preserver as if you fell off, you just got up.....hopefully not landing head first and getting your head stuck in the mud. Grin!

Later on, with decent HP tugging on you it was a lot easier maintaining control and getting up fast. On Slaloms, I found that the doubler handle ski rope went a long way in starting out and maintaining an even pull to help you learn how to keep things lined up and keep your balance.

I'll agree, just like anything else, experience in getting it right goes a long way toward success.

First time I skied was behind a 45hp Montgomery Ward motor on a 16' glass boat, don't remember it much, other than it was green. 2 skis of course!

The 427 powered Sanger we had (many years later) was set up for skiing. We could pull 2 bare footers up out of deep water starts. Plan there was to avoid pulling the rope right out of their hands!

 

[Texasmark]

First time I skied was behind a 45hp Montgomery Ward motor on a 16' glass boat, don't remember it much, other than it was green. 2 skis of course!

The 427 powered Sanger we had (many years later) was set up for skiing. We could pull 2 bare footers up out of deep water starts. Plan there was to avoid pulling the rope right out of their hands!

"45hp Montgomery Ward motor".......bet it was made by West Bend like Sears Elgin and Ted Williams initially, later going with McCullough for a mfgr. So West bend went to Chrysler (of which I had a 55 of that same design and their 3 cyl 85 design in 1971) which went on to become the Mercury's Force brand.

On the barefoot skiing, I got as far as one foot off the slalom and the water tickled my feet besides I wasn't all that much into the idea with water in your face where you couldn't see where you were going and if you hit an underwater object it went right into your foot. But I agree, to get doubles up barefoot you had to have some whoopie.

 

[ahicks]

Idea behind 427 Sanger ski boat was we would NEVER be limited by the amount of power available. We never were either.....