Need more oomph for skiing...

[nola mike]

Well, had hoped to be running a 4.3 this year, but it looks like at least another season on my tired 3.7L 19' bowrider, 1700#. Current prop 23p aluminum/quicksilver stock prop. Actually performs pretty well, gets out of the hole quick even when loaded, turns 45-600 rpm 48 mph solo, 4300 @45 with a few on board and a full tank. I just need a bit more to pull me out of the water on a slalom ski. It takes a lot to get me out, though it's doable with 2 on board. Nobody but me can get up on 1 though behind this boat. Really I just need a bigger engine. I don't want to switch props every time I ski if I can find a reasonable compromise. I want to buy something used on ebay, so a few different specific types/models/brands would be helpful. I definitely don't want to spend much on this since next season is DEFINITELY going to have a new engine

Choices?

1. 21p SS
2. 21p 4 blade
3. Last year a vented 23p was suggested
4. Anything else? How would a 23p SS treat me?

For that matter, what exactly do I gain with SS v. aluminum?

 

[alldodge]

My opinion, others will differ and be along shortly

SS blades are thinner so less resistance and no flex but heavier. AL blades thicker, more resistance, slight flex and is lighter.
Don't see SS gaining you much with your 3.7

21 4 blade more load then your current 23 AL

If you use the boat mostly for skiing, get a 21 AL (largest diameter you can find) and put some cup on it. You will still over tach at WOT but it will be closer to a 22, or if you can find a 22.

Note: with cup prop, reverse will not have as much bite

 

[nola mike]

1. So when is SS an advantage?
2. From what I've read, I thought 4 blade = better hole shot, mid range efficiency at the expense of top end?
3. The boat will be used 90% (miles wise anyway) for cruising. I'll ski 1-2 dozen times hopefully. Current setup is fine for other water sports including 2 skis, tubing, wakeboarding.

21p regular ol' aluminum sounds like a boring solution

 

[alldodge]

Again my opinion

1. So when is SS an advantage?

Always an advantage, less load to turn, and even with lower powered motors takes less power to turn.

2. From what I've read, I thought 4 blade = better hole shot, mid range efficiency at the expense of top end?

Yes they do, but.... They need more power to turn. More blades means more drag. If you don't have enough HP to turn it at max rpm's, then you wasting money. I don't think your 3.8 has enough. Also, the 4 blade has more lift, and if it is turned enough to get the lift, there can be a down side of porpoising possibilities.

3. The boat will be used 90% (miles wise anyway) for cruising. I'll ski 1-2 dozen times hopefully. Current setup is fine for other water sports including 2 skis, tubing, wakeboarding.

21p regular ol' aluminum sounds like a boring solution

Most used cruising, stick with what you have

 

[harringtondav]

The rule of thumb is trusty: 200 rpm change for each 1" change in pitch. As AllDodge states, 22P would put you to 4800 rpm. Perfect. And also give you more dig when pulling you up. 21P would improve the slalom yank more, but you'd need to use your right hand rev limiter, and you'd loose some max speed at 4800 rpm.

I believe the selling points for SS are thinner blades and less flex than aluminum, providing better performance than aluminum, as well as corrosion resistance in salt water. The other 'advantage' is more durable vs. minor dings. I boat in the Miss river where floating submerged logs, and snags from the latest flood are lurking. So I rarely use my SS. My aluminum props give up the ghost before a bent prop shaft or worse.

 

[Sea Rider]

For skiing only need the driver a spotter if it's a must have and the skier. Dump all other passengers to terra firme till your return. Check iif the slow hole shot betters with less load on board while maintaining current prop.

Happy Boating

 

[nola mike]

For skiing only need the driver a spotter if it's a must have and the skier. Dump all other passengers to terra firme till your return. Check iif the slow hole shot betters with less load on board while maintaining current prop.

Happy Boating

Yeah, pretty much already as light as I can go with just my wife and 8 year old on board...

 

[nola mike]

Ooph. Going down the propeller rabbit hole again. Making my head hurt. Now I'm thinking Laser 2 vented 21p v. maybe Mirage SS 21p?

 

[porscheguy]

Aren’t you located near colonial beach? I’ve got:
rev4 21p
mirage+ 21p
lazer2 23p
mirage+ 23p
mirage 23p
enertia 22p

You’re welcome to try some. The only one not in flawless condition is the enertia, and overall it’s still decent. I’m going to send it out in a week or so.

As I said, you’re welcome to try any of them so you can at least get a feel for their differences. I wouldn’t mind unloading all of my 23p props as I just don’t use any of them.

 

[QBhoy]

23” sounds a whole lot of prop especially if you are wanting it for skiing or towing. The 3.7 are known for their power for sure. So much grunt when they get going. Not a fan but respect their ability when they do stay running.
I’m a total stickler for a good 3 blade and one that’s well suited to the boat. If you don’t care too much for too soeed and efficiency...the answer lies with a hi five prop. There isn’t much better at giving big engine like pull with only a small 3.0 or 3.7 behind it. Efficient and fast they aren’t though.
I’d be tempted to drop a few inches and with a good 3 blade. Laser 2, tempest + or enertia are about the best of them.

 

[Sea Rider]

What's the max rpm range of that motor factory stated ? to check how much under if any that motor is to compensate with less pitch prop from current one ir order to gain more rpm. How much, that's the dilemma LOL!!

Happy Boating

 

[Bikestdy]

I have a '85 4winns 170 Horizon with a 470, last year I went from a 17p 3bl alu (bent on a submerged tree) to a 17 4bl alu (tried a 19p 4bl to bring RPMs down to spec-- but power felt weak, didn't ski with it, it became my spare) the 17p 4 bl made it feel like a different boat, it pulls much harder (but comes on very smooth). I use my boat almost exclusively for water sports and usually a have a full boat of people. I would tell you to try a 4bl alu it was a huge improvement on my boat. My prop are all Turning Point. Also made the boat feel extremely smooth, it never ran that smooth with a 3bl.

 

[Blind Date]

If you don’t care too much for too soeed and efficiency...the answer lies with a hi five prop. There isn’t much better at giving big engine like pull with only a small 3.0 or 3.7 behind it. Efficient and fast they aren’t though.

100% Agree! Nothing will pull harder out of the hole than a "High 5". That's what I have on my little 16' SeaRay OB with a MerCruiser 3.0 - 4 banger. IMO trying to do water sports with a 23P prop is insane. Even my CVX18 w/V8 power would be a slug turning something pitched that tall. You should being running a 19P something and do what you want but I wouldn't bother with an aluminum anything. Go with a SS prop and never look back.

 

[nola mike]

Well, been preoccupied with getting next year's new motor Picked up a hull with a 4.3 and it has a 21p Michigan wheels alum prop on it. K, not exactly a ferrari, but might as well throw it on and see how it does. Will try some skiing this weekend if the water and my wife cooperate.