Choosing the correct prop...

[markmdz]

So, I was thinking about a new prop, but don't have a clue about them, nor what to get.

So... I called Mike up at Checkmate and got his opinion. He suggested I get the Turbo Ultimate 4 14 1/4 w/23 pitch. Well, I took his info and spent some time out on the good 'ol internet and soon found myself completely lost.

Can someone explain to me how the difference in pitch effects performance?

Does anyone here run a 4 blade prop on their 'Mate? How does it compare to the 3 blade?

What is the advantage, if any, of running a stainless prop compared to an aluminum prop?

What's the 14 1/4 measurement refer to?

I know I've been real busy asking lots of basic questions lately, but I want to make sure that all of my purchases are educated, and correct purchases for my application.

Thanks in advance for any help you guys can provide.

If anyone has another reccomendation on a prop, please feel free to share. Good prop, bad prop, what's your opinion?

19'7" '87 Checkmate Ambassador - Blue on White.

[markmdz]

So, I was thinking about a new prop, but don't have a clue about them, nor what to get.

So... I called Mike up at Checkmate and got his opinion. He suggested I get the Turbo Ultimate 4 14 1/4 w/23 pitch. Well, I took his info and spent some time out on the good 'ol internet and soon found myself completely lost.

Can someone explain to me how the difference in pitch effects performance?

Does anyone here run a 4 blade prop on their 'Mate? How does it compare to the 3 blade?

What is the advantage, if any, of running a stainless prop compared to an aluminum prop?

What's the 14 1/4 measurement refer to?

I know I've been real busy asking lots of basic questions lately, but I want to make sure that all of my purchases are educated, and correct purchases for my application.

Thanks in advance for any help you guys can provide.

If anyone has another reccomendation on a prop, please feel free to share. Good prop, bad prop, what's your opinion?

19'7" '87 Checkmate Ambassador - Blue on White.

[Will]

Please anyone correct me if I am wrong. From what I have learned here on the board, I believe the 14 1/4 measurement refers to the diameter of your prop. I believe a four blade prop gives a lot more power but less top speed.(better hole shot with 4 blade, higher speed with 3 blade) And as far as the pitch, the higher the pitch, the lower your rpm's will be but the speed will be higher. Too much pitch and your engine may not be able to spin the prop in your rpm range at wot.

Oh yeah, everyone on this board will say a stainless steel prop is better than aluminum. I do not know exactly why though! http://www.checkmate-boats.com/6/ws/,s,8626072361/Graemlins/eyes.gif

Like I said, I may be wrong with any or all of that info. That is just what I think to be true from what I have read from this board. http://www.checkmate-boats.com/infopop/emoticons/icon_confused.gif

[Bill]

Good job Will!!! Stainless is better because of less flex in the blade to transfer the HP to the water. Flex is bad, aluminum is soft and will flex when a load is put on it, after a few years of use, aluminum will lose its shape, not to the eye, but it will.

2003 ZT 240 6.2litre/Bravo 320 H.P. 25P Mirage Plus

[Will]

Thanks Bill! http://www.checkmate-boats.com/6/ws/,s,8626072361/Graemlins/thumb.gif I am learning from the best! http://www.checkmate-boats.com/infopop/emoticons/icon_wink.gif

[vinny p.]

Will-- is pretty much correct. A 4 blade prop will give you a better hole shot but you may lose a bit of top end speed over a 3 blade. The plus side is that your mid-range or cruise speed will increase. That means your fuel economy will be better. With a 4 blade you can cruise at say 40 m.p.h. at 2800 r.p.m., where a 3 blade may need 3100 r.p.m. to get the same speed. The 4 blade will also bit the water better. Much less chance of blow out. You can run more trim as well.
Here is how the #'s work. The first number is the diameter of the prop. That means the width from tip to tip, if spun in a circle. The second # is the pitch. That number respresents the theoretical amount of forward travel a prop will go in 1 revolution, providing that there is no slip. So, by increasing pitch, you will lower your top end r.p.m., hopefully not losing any speed. If you over pitch, your motor will not be able to pull to a high r.p.m. Larger pitch also means less hole shot. Diameter acts in just about the same fashion.
The choice of steel vs aluminum depends on the type of boat and where you do your boating. If your boat is a fairly slow runabout, then the need for a steel wheel is questionable. If you are making alot of horsepower with a performance boat, then you have no choice but to go with steel. If you have a habit of running aground, then a steel wheel will last longer, however it can result in a broken drive. With aluminum wheels, the prop usually breaks first if run aground. The main advantage is that a steel wheel will not flex as much as aluminum.

[Will]

Yeah......that's what I meant to say! http://www.checkmate-boats.com/infopop/emoticons/icon_biggrin.gif Ya see what I'm saying......these people are experts.

[CHECKMATE ZEUS]

AND IF YOU RUN FAST ENOUGH TO RUN THE PROP BLADES OUT OF THE WATER, AN ALUMINUM PROP WILL 'BURN' ALONG THE BACK SIDE ABOUT 1/4 WAY UP AND EVENTUALLY THROW A BLADE. A STAINLESS WILL NOT. SO DO NOT RUN AN ALUMINUM OVER 50 MPH.

I am the one who knows all!

[175checkmate]

Everything right so far. I am currently running a 25p laser 2, love the prop. I also ran a 28p cleaver, nasty prop on my boat. I have a 14.5" 27p 4 blade ballistic prop that made the boat handle funny. No trouble turing it, but made the boat do strange things. The best thing is to try a bunch of different props on your boat to find one that works for you. A great hole shot prop will not be great on top end, same thing goes for a high pitch top end prop, it will be hard to get out of the hole.
One thing that has not been talked about is the term Rake. This is the props ability to lift the bow. Some props are designed to lift the bow, some the stern. This will depend on the type of hull you are running. What we have seen so far is checkmates need all the help they can get lifting the bow. There are a ton of varibles concerning props. How high the motor is will make props handle differnent. Below is a good prop calc. Plug in the numbers, 1st Engine rpm, 2nd Gear ratio, 3rd prop pitch 4th prop slip. The normal ratio for prop slip is 10%, some boats are better some worse but 10% works for the normal. ONe more thing, triming the engine or out drive will lift the bow, anything past neutral will eat speed. Good luck and have fun.
http://www.rbbi.com/folders/prop/propcalc.htm

http://www.checkmate-boats.com/6/ws/,s,8626072361/avatars/rooster_3.jpg


1975 Checkmate Tri-mate 2, 2.4 200+

[Bill]

And when it come to providing lift for the stern, you must have a lower unit that has the correct rotation.

2003 ZT 240 6.2litre/Bravo 320 H.P. 25P Mirage Plus