Ski Prop selection.

[zenon]

Hello,<br /><br />I have a 15-foot 2-inch runabout I use exclusively for slalom skiing @ 36MPH.<br />I care ONLY about skiing performance.<br /><br />I'm re-powering it with a 115hp evinrude and am wondering what prop I should start with.<br /><br />I'm guessing after reading the prop FAQ that I want an efficient, largest diameter prop I can find. Any Ideas/suggestions?<br /><br />I'm most concerned with my pull @ 36MPH and minimizing slippage (holeshot's not a major concern, my current holeshot sucks so bad anyway) so when I pull boat speed stays as constant as possible.<br /><br />I'm thinking maybe one of ballistic props on sale might do the trick.

 

[Dhadley]

Re: Ski Prop selection.

A lot depends on your hull and set up. Tell us more about that. Does the hull have a pad or step? How many lifting strakes? Are you going to use a jackplate? If so, how much set back?

 

[zenon]

Re: Ski Prop selection.

Unfortunately the boat is put away for winter but I can tell you that with its current 60hp I can get 36MPH with just me in the boat. Also pulling me (165 lb) through a slalom course full throttle is about 26.<br />I don't know the specs of the prop but I know it's nothing special, the stock prop that came with a 60 johnson I'm sure.<br /><br />the boat's a 15-feet 2-inches bowrider but the hull design looks exactly like this one:<br />http://www.boats.com/sites/mclarensmarina/gallery?style=dw&entityid=100723021&mid=null&galleryBack=%2Fsites%2Fmclarensmarina%2Fboat%3Fentityid%3D100723021%26mid%3D2426%26showDL%3Df alse%26showMD%3Dfalse%26clk_srclnk_name&baseurl=%2Fsites%2Fmclarensmarina&pic=1<br />If I had to gess I'd say there's probobly 3 or 4 chines per side.<br /><br /><br />Jackplate? that sets the motor away from the back of the transom, right?<br />how will that affect things? is it just for holeshot?

 

[LubeDude]

Re: Ski Prop selection.

The more blades, the more holeshot, I dont know if you can get a five blade for an evenrude or not, but my Highfive on my merc 150 will pull stumps if I wanted it to, also my holeshot is next to a rocket launch. I seiously think I would break your tow rope or pull your arms off if I just hammered it.

 

[sangerwaker]

Re: Ski Prop selection.

Lubedude, easy there big boy! That's quite a claim. I'll take your arm pulling challenge any day! I have a 200 with a 21 pitch high five and take off hammer down every day! And no my rope won't break, even if it is only 3/16" diameter. It has a 4500 lb break strength! Good stuff!<br /><br />Zenon, yes you can get a high five for that motor, but it may require some custom machining to fit depending on the year of the motor. My old boat was a 16' Forester with a '91 Evinrude 120. Great ski boat. The Ballistic props were OK. That was my first stainless, too. I would start with a 19 if you go with that one. I tried a LOT of props on that boat, including a machined high five. Best performance I got was from a Turbo 17 pitch. Holeshot like you wouldn't believe and about 42 mph without using the trim. For ski performance, don't use the trim while skiing, it only destroys the wake quality.<br /><br />BTW, I used the Forester almost exclusively for barefooting.

 

[zenon]

Re: Ski Prop selection.

What boat is that in your sig? more pics?<br /><br />We've tried trimming the motor and I think my dad said it goes about 30MPH trimmed when I'm not cutting, and then when I cut the back-end of the boat washes all over the lake and the speed difference from cutting to coasting is so bad it's not worthwhile. (worst pull ever!)<br /><br />Is there something you'd suggest over the ballistic? My hugest concern -way moreso than holeshot- is how much slip the prop will have at speed -36MPH- since a perfect pass is out of my budget (do they even work with outboards?)<br /><br />The ONLY thing I care about is that it MUST be able to pull me through the course @ 36MPH. do you think a 115 with a 19in pitch Ballistic will be able to do that?<br /> http://www.propellersonline.com/BallisticE85.php <br /><br />here's the 2 places I've found so far to find props, are there any other props you think might be better?<br /><br /> http://www.iboats.com/mall/propfind...rd&horsepower=115&year=1993&url_mode=standard <br /><br /> http://www.propellersonline.com/outboard.php <br /><br />thanks so much for the help.<br /><br />BTW: I also found an avenger with a 200 johnson for sale, I'm still tying to figure out if its sold or not.

 

[zenon]

Re: Ski Prop selection.

BTW how much $$$ are these older forester's used?<br /><br />how are rapture's? this looks like a good deal on a 19in.<br />http://www.iboats.com/mall/propfinder/?*******=833637871&search=Product&prop_chart_relation_id=9262&manufacturer=Johnson&rotation=Standard&horsepower=115&year=1993&chart=18&pitch=1 9.00&url_mode=standard

 

[sangerwaker]

Re: Ski Prop selection.

Howdy zenon. Before we go into the specifics on a prop, we gotta find out more about your set up. Do you have a tachometer? If so, do you know how many Rpm's your motor is turning at full throttle? At that rpm, where is the trim set? And lastly, what type (alum or ss) and size (diam and pitch) are you currently using? Also, where is the motor mounted (vertical position) on the transom? Your heighth of the cavitation plate (the horizontal surface above the prop) should be about even with or no higher than 1" above the bottom of the v (the boat) when trimmed down fully. This works best for skiing and will help keep your holeshot.<br /><br />I can't tell you where to buy a prop, but that deal on the Rapture is sweet! I never tried one of those, so I can't speak of their performance.<br /><br />What year is your 115?<br /><br />As for your course skiing, you will always pull that boat around. That is why tournament inboards and outboards have at least one fin under the hull. My old Forester would get pulled around too. It does help if you install a pylon if you don't already have one.<br /><br />As for the boat in my avatar, it is my new (to me) boat. 1997 Sanger Barefoot. 200 Merc EFI. Works really good for slalom, too.<br />

 

[LubeDude]

Re: Ski Prop selection.

Originally posted by sangerwaker:<br /> Lubedude, easy there big boy! That's quite a claim. I'll take your arm pulling challenge any day!

LOL, well, maybe I was a bit over zellous. But they do pull hard.

 

[Dunaruna]

Re: Ski Prop selection.

Zenon, I'll leave the prop selection to the experts (lubedude & sangerwaker) but I can tell you that my first boat was almost identical to your picture link, back then I liked to slalom hard (too old now), I ran a merc 50 and then upgraded to chrysler 115. Assuming the 115rude is 100% then with doulbling the horses you will gain conciderable holeshot and it won't bog down on tight turns - now its back to prop selection..........<br /><br />Aldo

 

[zenon]

Re: Ski Prop selection.

*phew* very nice boat!<br /><br /><br />here's some actual pics of my boat (really bad quality)<br /> http://www.photo.net/photodb/folder.tcl?folder_id=433846 <br /><br />Do you have a tachometer?<br />no, I want to get one for next summer<br /><br />where is the trim set?<br />from my trim guage I'd say trimmed out about 1/2 way and it starts to kick up a decent spray and I don't like to take it much more than that or it'll porpise over waves.<br /> <br />alum or ss<br />stock aluminum prop for a 60hp.<br /><br />diam and pitch<br />don't know yet, I'll try to get that info<br /><br />where is the motor mounted (vertical position) on the transom?<br />from memory I think it's as low as it'll go.... I think the cavitation plate is even with the bottom of the vee. I'll try to get better info on that too.<br /><br />the 115 is a 1993

 

[sangerwaker]

Re: Ski Prop selection.

That boat should work well for you, especially after putting on the 115. Sounds like you have everything set up good so far. Be sure to mount the new 115 in the same vertical position. Very important to install a tach and check it's accuracy. It's the only way to properly size a prop. Wouldn't want to see you turn too many rpm's and blow it up! <br /><br />I think you are pretty maxed out on your current motor. Without a tach it's hard to tell. 36 mph for a 60 pulling a slalom skier cutting is asking a lot. <br /><br />Does the 115 come with a prop, even if it's aluminum? Another idea is to go to your local prop shop after installing the 115 and buy a prop. Many of them will loan you props until you find one that works. I would just hate to see you spend the $ on that Rapture and find out you don't like it. Although that is a smoking deal! I think that prop would do well, but I am only guessing.<br /><br />Where you at in Canada, zenon? If you go to my homepage ( barefoot central ) there is a locate a footer page to find footers worldwide. See if there are any footers near you. They may slalom ski or know someone who does. Otherwise if you get to the MN area, look me up.<br /><br />There's some pretty cool videos on that site, too.<br /><br />Good luck and keep posting!

 

[troska]

Re: Ski Prop selection.

Zenon,<br /><br />I run a 13.75 x 15 with a Johnson 90 on a 17 foot boat. WOT it will pull me at 32 mph. I've also run a 17 pitch, and that will pull me at 35-36 mph, WOT, not trimmed. I run the 15 pitch because I'm a big guy, and I also weight the boat for wakeboarding.<br /><br />If you can get up on one with a sixty, you should be doing great with a 13x19 Al cheapie prop on the 115. Like Sangerwaker said, start there and you might not have to spend the bucks on a special prop.<br /><br />Tim

 

[sangerwaker]

Re: Ski Prop selection.

Tim, what year is your 90? Sounds like you have a newer model that has the larger gearcase and different gear ratio. My brother in law has the same set up, but his prop is larger, like yours 13.75, not 13.25 like zenon will need to fit his 115.<br /><br />Yup. '95 they changed from a 13 tooth spline to a 15 tooth, and got a bigger prop.

 

[Boilermaker]

Re: Ski Prop selection.

Johnson still makes a 13 spline 14"diameter ALUM. prop>>><br />From what I have read here, the TURBO series props are great props, if your willing to spend some time tuning your setup. I have the Stiletto 13.25 x 17 on my 1978 Johnson 115 & LOVE the prop. Same manufacturer as TURBO, but is a little more forgiving in the setup.

 

[zenon]

Re: Ski Prop selection.

Actually I'm from Winnipeg Manitoba, real close to Minnesota. <br />If you'll teach me how to barefoot I'll swing by next summer for sure!<br /><br />how long are most of those 'footing ski boats with outboards?<br />My dad hates inboards and is now refusing to overrate our boat :-/ (rated @ a 90) :-(<br />Our boathouse is also sized for the small 15-foot boat we have now :-(<br /><br />So I may not have any other option but to get a boat.<br />The avenger's been sold :-(

 

[sangerwaker]

Re: Ski Prop selection.

All of the outboard barefoot boats are about 20' and usually come with a 200 hp of one brand or another. There are none currently being made, you will need to look at used. Most of the major ski boat manufacturers have made them-Malibu, Sanger, Ski Centurion, Ski Brendella, Mastercraft, I think Ski Nautique for a short while, too. Be forewarned, tournament ski boats hold their value incredibly well, so don't get sticker shock. Go to the link above (Barefoot Central) and look at the used barefoot boats. There are a couple of good deals there now. That is the best place I found to look for this type of boat. It's where I found mine! <br /><br />As for you coming down to my neck of the woods, c'mon down! I love to teach people to foot. I can promise you that you will be footing (on the boom) in less than 1 hour. I have lots of extra gear, so don't worry about that. <br /><br />P.S. Looks like about an eight hour drive to the Twin Cities for you.

 

[troska]

Re: Ski Prop selection.

It's a '93. 15" pitch has a diameter of 13.75 for mine, but when you go up to a 17" pitch, the diameter drops to 13.25. If I'd jumpt to a 19, the diameter is 13 even. <br /><br />Even though it is commonly ignored, diameter does play a roll in WOT rpm. I have the same WOT rpm fully trimmed with both the 15 and the 17 prop, attributable to the increase in diameter.<br /><br />Tim<br /><br />

Originally posted by sangerwaker:<br /> Tim, what year is your 90? Sounds like you have a newer model that has the larger gearcase and different gear ratio. My brother in law has the same set up, but his prop is larger, like yours 13.75, not 13.25 like zenon will need to fit his 115.<br /><br />Yup. '95 they changed from a 13 tooth spline to a 15 tooth, and got a bigger prop.

 

[BF]

Re: Ski Prop selection.

Hi Zenon.... Note I'm from the 'Peg too. It seems that you're jumpin' the gun a bit. No sense worrying about the prop if you don't know even if you're gonna upgrade the motor. Your current boat would be a nice ride, it's just a bit underpowered. My lake neighbor has a very similar looking boat (might be a foot bigger, but sure looks like yours) and he's got a 120 Johnson on it.<br /><br />If your Dad doesn't want to exceed 90 hp, an 80-90 hp should still be a world of difference compared to where you are now. I think it should easily be able to pull a 36 mph pass.... Of course some throttle modulation will still need to be done on whatever you have. Running a lower pitch prop will help, but the amount of slip will vary depending on your pull, so I don't think it'll ever be a "just set the throttle and steer" proposition to get a good constant 36 mph. I have a 16' ski boat with a V-150 merc. It has a 19" pitch aluminum 3 blade... If you had an 80-90 hp, a 17" might be better. If/when you upgrade your motor and do so at a local boat sales place, talk to them before hand about propping. They might be willing to let you exchange for a different pitch if you're not happy, or maybe would let you try 2 and keep the one the works best. There are some very good helpful people in town. Larry at AVO, Barry at Sportsman Enterprises.... both upfront guys that have been in business quite a few years. Sportsman doesn't sell motors anymore, but they will order prop's and parts for you.<br /><br />BTW, I've seen lots of folks barefoot behind boats in the 90-115 hp range, so you'd probably be OK for that too if you upgrade.<br /><br />What lake do you ski at?

 

[BF]

Re: Ski Prop selection.

oh and I forgot to mention, you won't notice when you're skiing, but your driver will tell you that the engine rpm's are going down when you pull... so, it's probably mostly a lack of torque problem. If it was only prop slip the rpm's would be unchanged. Have you ever tried a lower pitch prop on your current motor? It's pretty heavily loaded even with the boat alone. It won't pull 36, but it might pull an honest 28 or 30 with a lower pitch prop.