4 vs. 3 blade propellers, which brands are better?

[stevens]

Hi guys,<br /><br />I need some advise on the correct prop to choose for my boat. Here's the situation:<br /><br />21' daycruiser, 120 HP inboard Mercruiser diesel, Alpha drive, about 2650 lbs dry weight, V-hull, and now also with Smart Tabs that work great. The boat generally handles well and planes easily.<br /><br />The boat came with a 23" Black Max alu three-blade propeller, and did about 36 knot at WOT of about 4200-4300. Slip was about 13%.<br /><br />I switched to a 21" Ballistic steel propeller, and it now does about 34,5 knots at WOT of 4500, which is the highest the engine will go. The slip calculates to about 8-9%.<br /><br />The rated RPM is 4400.<br /><br />Now, the Ballistic doesn't like to be trimmed out much and will soon ventilate. In other words, apart from a better holeshot and a smoother ride, this prop change didn't do me much good.<br /><br />Also, I bought the prop online from the US, and with no return possible. I better hit it right the next time.<br /><br />So, before I blow any more money on this, I need some expert advise from you. Please pipe in.<br /><br />A good hole-shot, a good grip in the small chop, and a comfortable ride is what I am after. We rarely go at WOT, so top end speed is less of a priority, but it probably shouldn't go down any more. Finally, it is a diesel that is quite noisy, so if we could reduce rpm's somewhat without losing speed, that might be good.<br /><br />First of all, which brand and model of steel prop do you think will give the best allround performance without blowing my budget? Stiletto, Turbo, Rapture, Vengeance, others?<br /><br />Secondly, 3 blades or 4?<br /><br />Finally, which pitch should I choose. Back to 23"? What if I go with a 4 blade, does that affect the pitch as well?<br /><br />As you can tell, any qualified input would be appreciated.

 

[walleyehed]

Re: 4 vs. 3 blade propellers, which brands are better?

Based on the numbers on RPM you list, your slip rate only changed by 1/2%....."less", but speed is less too, even with a 200RPM increase to the rev limiter, you only gained .5%(Less than 1%) based on speed vs. RPM.....not good.<br />Your slip rate should have dropped more, with the same speed or more with a 200RPM increase, going from alum. to SS.<br />

Stevens, this is what I posted on the other thread...<br />I re-run the numbers based on the speed you give here...<br />I'm not seeing a 4-5% decrease in slip....your're 200RPM more, but 1.7MPH slower...it's almost an even trade, slip-wise...<br />I see this with the Ballistic all the time...that's a big reason the numbers don't add up to convince me to use one. I know it's easier when you have 25 props setting on the dock to run, one right after another, but my data shows this prop to be very inefficient for an SS prop...very simular to alum in most cases.

 

[walleyehed]

Re: 4 vs. 3 blade propellers, which brands are better?

My opinion only, here, but my choice would be a Turbo 1 in a 14-1/4X22, 3-blade of course.<br />4-blade will give better hole-shot by a bit, but we have no way to optimize the performance of a 4-blade by lifting the drive up, so...it will be slower than it's 3-blade counterpart.

 

[stevens]

Re: 4 vs. 3 blade propellers, which brands are better?

Walleyehed - Thanks for running the numbers again.<br /><br />I agree that the Ballistic didn't change much relative to the Black Max, and probably the biggest change came from going down in pitch.<br /><br />Any views on the other questions above? I.e. brand & model, number of blades, pitch?<br /><br />I wish I had known you before I blew $500 on the Ballistic (that includes local VAT, freight and handling to here).<br /><br />Edit - our responses crossed each other. Thanks for the suggestion. A 3-blade Turbo 1?

 

[walleyehed]

Re: 4 vs. 3 blade propellers, which brands are better?

We posted at the same time...I gave a bit of a run-down on what I think....se what some others think too.

 

[stevens]

Re: 4 vs. 3 blade propellers, which brands are better?

Thanks for the input, Walleyehed.<br /><br />Just a follow-up question; why did you pick the Turbo 1 over the Stiletto?<br /><br />Also, the Stiletto is vented and the Turbo 1 is not? I think venting is a positive for my engine as it allows the revolutions to come up a bit so that the turbo kicks in sooner. But then again, if ventilation is a problem with the Ballistic, force feeding it with exhaust surely can't do much good...<br /><br />Anyway, thanks again.<br /><br />Any opinions from anyone else?

 

[walleyehed]

Re: 4 vs. 3 blade propellers, which brands are better?

Venting is no problem if needed...All of my Turbos have vent holes, some came that way, others I've drilled out to larger sizes.<br />Stiletto would be fine, but I like the mid-range and top-end of the Turbo. The good mid-range means better cruise economy, that's always a plus.

 

[stevens]

Re: 4 vs. 3 blade propellers, which brands are better?

How about those other brands that advertise a lot on the net, i.e. Hustler, Express, Speed Zone, Powertech, etc. Do any of these stand out as particularily good, and would any of these match the Turbo?<br /><br />Also, the lowest price I can find on the Turbo is $270 at boatownersworld.com - does that seem about right?

 

[walleyehed]

Re: 4 vs. 3 blade propellers, which brands are better?

270 for the Turbo sounds pretty good.<br />Of the props you mention above, the powertech would be my first choice for the fact they build a prop to match about anything and will continue to tweek it for you until it gets you where you want to be...BUT, it will not out-perform a turbo....

 

[stevens]

Re: 4 vs. 3 blade propellers, which brands are better?

Walleyehed - thanks again for your input, this is really useful.<br /><br />I have complete trust in your recommendation. So, I just found & bought a 14 1/4 x 23 Turbo on e-bay, used but spotless, at $185. Seems like a good deal, and cheap enough for me to be able to sell the idea to my wife that I need to buy a second new propeller.<br /><br /><br />

<br /><br /><br />This should work, I hope. Given that the smart tabs help to get me on plane faster, the added pitch should lower rpms a bit and give a few more knots in top speed. Hopefully, it will trim better and ventilate less than the Ballistic.<br /><br />I'll let you know how this goes.<br /><br />Then I'll just have to find someone over here who'd like a spotless 21" Ballistic at a bargain price....

 

[stevens]

Re: 4 vs. 3 blade propellers, which brands are better?

Just out of curiosity, can anyone direct me to any propeller tests published on the internet? Preferably some that include Ballistic, Turbo or Black Max propellers? I've searched around but haven't found much. Thanks!<br /><br />I am probably just going through a process called post-purchase rationalization, i.e. looking for confirmation that I bought the right thing. Kind of like when your wife asks "Do I look nice in this dress?"

 

[dutch135]

Re: 4 vs. 3 blade propellers, which brands are better?

Stevens,<br />If you don't end up liking that 23 pitch prop, I might be interested in it. I was watching that prop also, but still want to sort thru my own applications and see what would be best for my boat.<br />good luck!

 

[stevens]

Re: 4 vs. 3 blade propellers, which brands are better?

OK - thanks. You're probably aware of this other one on e-bay too then (Item number: 4555591413).<br /><br />I guess I couldn't tempt you with a spotless Ballistic?

 

[dutch135]

Re: 4 vs. 3 blade propellers, which brands are better?

um,,, thanks,,,,<br /><br />but i'm running a 21 aluminum now, <br />not sure if that would be enough to <br />drop my RPM's down a couple hundred,,<br /><br />let us know how the new one works out for you!<br /><br />btw, how much is shipping going to be for you?

 

[stevens]

Re: 4 vs. 3 blade propellers, which brands are better?

Dutch; just kidding about the Ballistic.<br /><br />Here's how the numbers work out:<br /><br />$746 Local price of new Turbo prop<br /> <br />$185 Ebay price on "nearly new" in the US<br />$18 UPS domestic to my mailbox<br />$119 Shipping overseas & handling<br />$51 Local VAT<br />$374 Sum<br /> <br />$372 Net saving<br /><br />The high cost level over here makes it worth it to ship a lot of things over. There's nothing like free enterprise!

 

[stevens]

Re: 4 vs. 3 blade propellers, which brands are better?

Just an update; I took the boat out for a spin tonight to really check on how the Ballistic prop behaves.<br /><br />Everything said about it ventilating is true! When trimmed out, in sharp turns, even when coming down from over waves. Every time, the solution was to trim the drive further in, with a resulting lower bow and lower speed.<br /><br />Hole shot is still great though, and there is very little vibration to be noticed. Very smooth and responsive.<br /><br />I can't wait for the new Turbo prop to arrive in a week or two. I'll keep you posted on how it goes.<br /><br />If Stillfishing or Dutch135 have received their new props, it would be interesting to hear from them too.

 

[stevens]

Re: 4 vs. 3 blade propellers, which brands are better?

Question for Walleyehed or anyone;<br /><br />I just received the new (used) Turbo prop in the mail today. Nice and shiny, heavy, but not identical to the one pictured on Ebay. The one pictured on Ebay was vented, but the one I received had no vent holes.<br /><br />How do you think this would affect performance? Does it matter, or should I just try it on and see how it goes? If needed, I could always have some vent holes drilled in later, right?

 

[ufm82]

Re: 4 vs. 3 blade propellers, which brands are better?

Stevens, since you are running an inboard engine the vent holes are not going to do anything for you. The venting in props is only there for 2-stroke engines that have very little torque at take-off. They help aerate the water behind the blade and let it slip more, allowing it to spin up faster and get the boat out of the water. The inboard engine, being a 4-stroke with a heavier internal mass and more torque doesn't need the venting. In fact, most sterndrives will not benefit at all from a vented prop- it just doesn't need the extra slip. <br /><br /> And, and this is a big one here, most sterndrives DO NOT exhaust through the hub anyway so the vents are a moot point. A thru-hull exhaust is a perfect example- a vented prop won't do anything on that boat as there is NO exhaust flowing through the hub. So, the vents not being there won't make a hill of beans difference on your boat. Don't ruin a good prop and drill holes in it. <br /><br /> Wow, $118 for shipping? That certainly hurts. <br /><br />UFM82

 

[stevens]

Re: 4 vs. 3 blade propellers, which brands are better?

UFM82 - Thanks! I think you're right. Here's a link to the specification for my engine & drive.<br /><br />It does have a through-hub exhaust. However, take a look at that torque curve. I don't need extra rpm's for higher torque on take off, I need less!<br /><br /> Spec<br /><br /><br />Shipping & handling turned out to be about $80, which was not as bad as expected. The worst part is the 2-3 week delay in getting stuff.

 

[walleyehed]

Re: 4 vs. 3 blade propellers, which brands are better?

If the unit you have has thru-hub exhaust, it works the same way as any outboard or sterdrive with thru-hub exhaust...and yes, the vent holes can be utilized with your rig.<br />The print on the linl is too small for me to read, but as I said, if it's thru-hub exhaust, it works exactly the same.