Modded 3.0 Johnson with MAD EFI

Yep, on the triple they are between the outside motors and the middle motor, so they are probably about 24" apart.

Steering would be fine, just don't mount the eyes too low on the transom or the towed weight will actually lift the back of the boat up and cause cavitation.

 

What height do you think, about half way between the upper and lower motor mount bolts?

jim

 

Both of our multi rigs have the tow rings mounted near the bottom of the splashwell. It's probably about 2 inches from the bottom of the splash well to the center of the bolt for the tow ring. They also have backer plates, or go through the motor mount plates to help spread the load.

 

Not to get in the way here, but WOW! I am privileged to be a bystander in this thread, thanks to the Club members/ drivers for the most excellent education. And how can we not thank Jim for bringing this subject to the current level of expertise and development.
Thanks to all of you for the fine discussion!

 

Another reason for keeping the tow eyes a little higher is to help keep the tow line out of the props. It's a real pain when you have to unwrap a leader or tow strap from around a prop, not to mention, hoping you didn't do any damage to the motor or driveshaft.

 

Tim,

I learned a lot too.

Let's talk about props for the 18. Props for Merc, Evinrude, and Yamaha, both small block and big block. I know you team guys have probably tried about everything. I would like to consider strictly best pulling power.

I know what I like for my purpose, but I don't have to pull real hard.

jim

 

Twin and triple rig applications: Merc Mirage or BRP's new Rebel in 15 or 17 pitch. These props have very large blade area and not much cup. 15 is preferred unless you have a 2:1 gear ratio then you may need a 17 to be sure you are not all over the rev limiter at 40 mph.

Single rig: Big block I'd stick with a Mirage, Rebel or a regular black SS prop from Evinrude as they have almost no cup.
Small block I'd be sure it is a plain black SS prop from Evinrude or Yamaha or Mercs regular non polished SS props. The small blocks cannot handle the loading that the cupped props put on them and rev much more freely with non cupped props. I have not played with vent holes on SS props much at all. 16 pitch is my favorite size for single rigs, then 15, then 17.

Alot of this depends on what you want to pull with a particular boat. We have the luxury of a triple rig and a big twin. The triple has 15 Mirages and the big twin has 17 Rebels for pulling barefoot pyramids etc. My twin easily pegs the 50 mph Airguides.

 

Thank you for that. I guess you have run into the reluctance to try the low pitch props like you recommend by the general public including most motor dealers and prop shops. It is rare to find one that understands the needs of an outboard ski boat.

I hope the members that are shopping for props will heed your advice because it represents a lot of trial and error. Higher pitch than you recommend will decrease the performance for skiing.

Folks, if you want to pull hard and have the best speed control do what he said.

jim

 

I have been planning on going with a 17 pitch for my "standard" prop, but wouldn't mind eventually getting a 15 or 16, and a 19 for various other purposes. Does anybody know if going up to a 19 would help save some gas when pulling higher speed skiing with low numbers (1-2 people)? Chances are good I will be pulling a LOT of barefoot and jump practices. I would think that running a lower RPM for the same speed "may" increase the fuel efficiency some. Any advice that way?

 

I think the only way to know for sure is to try it with your set up, or find someone that has. My opinion is that the speed control will suffer some. I do think that a completely uncupped prop will spin with less drag and save some fuel.

jim