Will a prop change make a difference?

[porscheguy]

I checked out their website and saw the same thing. It’s a bit odd because I think the laser2 was the first prop mercury used PVS on. It’s also odd that they’re showing a picture of a prop that clearly has vent plugs.

Anyway, I’ve got a 23p laser2, and I think I live close enough to you that you’re welcome to try it out.

 

[achris]

EDIT: Looking on the merc website, says the laser II is for bass boats/outboards, and does not have the performance vent system?

Laser II DOES have vent slots, and the 'bass/outboard' recommendation is just for the website. Been running Laser IIs on stern drives for years, nothing wrong with them. They work beautifully.

Chris.......

 

[Scott06]

Prop MD also does a pitch exchange via mail. I would suggest a 4 blade as I had very good results on a 3.0 with Michigan vortex 4 blades. Relatively cheap being aluminum and made a huge difference in holeshot. What gear ratio is in your drive ? 1.84?

 

[achris]

Prop MD also does a pitch exchange via mail. I would suggest a 4 blade as I had very good results on a 3.0 with Michigan vortex 4 blades. Relatively cheap being aluminum and made a huge difference in holeshot. What gear ratio is in your drive ? 1.84?

Stock 3 litre engines are 1.98:1

 

[nola mike]

Laser II DOES have vent slots, and the 'bass/outboard' recommendation is just for the website. Been running Laser IIs on stern drives for years, nothing wrong with them. They work beautifully.

Chris.......

Must be a typo on the website. Says no PVS, but you can see the vents in the pic...

Prop MD also does a pitch exchange via mail. I would suggest a 4 blade as I had very good results on a 3.0 with Michigan vortex 4 blades. Relatively cheap being aluminum and made a huge difference in holeshot. What gear ratio is in your drive ? 1.84?

Yeah, I'm 1.84. Head's starting to swim the more I look into this!

 

[Scott06]

Yeah, I'm 1.84. Head's starting to swim the more I look into this!

that has you at around 12% slip which isn't bad for a basic aluminum prop. It can be confusing until you try a few props and see how pitch and blade number can move things around. For me playing with the aluminum Michigan vortex 4 blades was a good inexpensive way to cut my teeth. Ended up with a 16" for skiing and 18" for general cruising and tubing.


I was going to reccomend if skiing is your thing try a 20" vortex 4 blade or alpha 4 based on what numbers you gave.

I found much better pull skiing (I'm 270 lbs) lower planing rpm but traded 3 mph top end which I rarely used. Generally you're trading holeshot for top end or vice versa. Really comes down to down to how you use your boat the most.

 

[nola mike]

I don't care about top end at all. I do care about cruising efficiency, which for me is around 3k rpm/30 mph.

 

[Bikestdy]

I currently have a 23p aluminum prop on my 3.7L alpha one. It's propped correctly, hits 45-4600 rpm with a 47-48 mph top speed (used to hit 49-50, old boat now).

Just wondering what brand prop you are currently using? I have and '85 4Winns 170 Horizon (17') with a Mercruiser 470 and those speeds are only what I have dreamed of (granted I haven't played much with props). Currently I have a Turning Point 19p 4 bl aluminum and it hits 37mph@4000rpm WOT, but I think I need to drop to a 17x4 to get the hole shot I am looking for, for skiing. I was hoping to crack 40 with current prop, but not quite. Granted the 4 bl is probably slowing it a bit, but I don't think I could turn a 23p with what I have seen, maybe your hull is just faster.

You can check my post as I am searching for a prop as well with a very similar boat/powertrain.
https://forums.iboats.com/forum/gen...0-prop-selection-help-tp-solas-michigan-wheel

 

[Chris1956]

Mike, Propping the boat for max speed will give best efficiency at cruise speed.

Alternatively, propping the boat for hole shot is like driving a car in 3rd gear. Not the best for highway cruise speed.

 

[nola mike]

Mike, Propping the boat for max speed will give best efficiency at cruise speed.

Alternatively, propping the boat for hole shot is like driving a car in 3rd gear. Not the best for highway cruise speed.

That's why the vented prop sounds so cool. Like it shifts gear. I'm still not quite clear on the effect of aluminum v. ss or 3 v 4 blade.
Bikestdy, Using generic aluminum prop. Presumably whatever quicksilver the boat originally came with. Sounds like something wrong with your engine/tuning/waterlogged hull/etc. A 3.0 should hit low 40's on your setup. My weight is #1700, and even with 1000# of gear I can hit 40 no problem.

 

[Bikestdy]

It looks like it is the weight difference, my boat is about 2100 dry, loaded and half tank of fuel I'm probably around 3200lb. In my sales brochure it talks about being able to hit 45 (but doesn't really say a top speed), so with a 4 blade i will be slower, i think a 3 blade 21p would get me there.