Props
 

I had a question on props...

I am running a 1989 Checkmate Sportfire 18 with the stock 205 hp 4.3 mercruiser. What is the most optimal prop for this setup?? I was thinking about a Land and Sea Torque shift. Any comments on this??

Contact Mike Combs factory direct @ 419-562-3881 ...he can help you out!

My first checkmate was a 1996 persuader 183. This is basically the same boat you have just called a different name. I had a slightly modified 4.3 and the best prop that worked was a mach sterndriver 24 4blade. Mach is no longer in business but you can probably find a used one. Actually I know a dealer that has a few mach props still in stock. If you want to contact me and I'll give you their number and you can call them and see what they have. I now have a convincer 259 that I'm having all kinds of problem trying to find a prop that will work on it. Every prop works differently on every application.

The boat is a 259 convincor. 572ci 680hp. It also has a high X dimension. I've tried quite a few hydromotive props but they all had the same problem with getting on plane. They slip so bad out of the hole. I'm using a merc 26 4 blade spinning 5600 rpm. This prop causes serious, I mean serious chine walk at high speed. I'm still trying different props.

why is the X dimension high ??

seems to me you should put it back to stock height and you will be more stable and won't be having prop issues.

I have a 253 with 100 less HP than you, and i run a 27 hydro with no problems or slippage 5300. Also, it's pretty stable at 80mph.

Ted,

I had very similar problems on my 242 Convincor. Every Bravo I prop I tried chine walked like a mo-fo. Your answer may be in taking a Hydro-motive and adding 1in on the defuser ring. This will help with getting on plan. You can also add a slight roll on the tip/leading edge which will will help with slip. You may also want to try a prop like a Patriot. Its design is similar to Hydro, but it has more rake, thus giving better cruise and lock-up at lower rpm's. By the way, what gear ratio do you have? If you are 1:50 I would think that you should be using a much larger prop. If you are 1:36 I would think that you should be slightly larger than 26 pitch.

The drive is a bravo 1 xz. You are right I should be turning a much bigger prop. This 26 is spinning a little over 5600rpm. I tried a 30 merc. turned if I remember correctly 4900rpm, very slow getting on plane and chined walked bad at speed. The dealer I bought the boat from had a 253 with massive hp. He had the same problem with chine walking starts at about 80 if you can drive out of it levels out about 90. Unfortunately I don't have quite that much hp to even attempt to drive out of it. I did try the defuser ring on the hydro's. It definately helped. On flat water worked great getting on plane and most importantly no chine walk like the mercs do. Any thing over about a 1 ft chop the hydro's would just spin out trying to get on plane. I looking for some mach's (the patriot) to try. If I can find something that works close then I can have it worked on. How do you like your 242? I had a 1996 242. Had the basic 7.4l but put a procharger on it. I never had a prop issue on that boat. Probably mine was just short of the speed where the chine walking would start.

I have a Convincor 270 w/496Mag. Tyler Crockett reworked the engine and it dynoed at 550hp at 5400 rpm. I still have the same prop on the boat as before the engine was modified, a Hydromotive Q4 23 pitch. I went from 60 mph at 4800 rpm to 72 mph at 5400 rpm. Tyler said to get the rpms down to about 5100 to 5200 rpm. I was thinking about trying one of those Acelerator props from Houston propellers. I just haven't gotten around to it.

Ted, you may want to consider full hydraulic steering, if you don't already have it. I have a 251 convinsor currently with a 468 BBC (550hp). Best top speed are usally with a mirage 3 blade. But then you do get chine walk. I moved my tabs in as close to the drive as possible and installed full hydrualic steering. Chine walk was decreased significatly, then I tried a Hydro QIV and it eliminated chine walk totaly up to 80mph. Over the winter I am installing a 572cu BBC Normally aspirated. I plan to tune and dyno the motor in Late January and hope to see 650 plus hp. With a Bravo drive I tend to be very easy getting out of the hole so my planning times always seem long. Good luck, I'd love to hear more about your motor. Dave

Thanks for all the responses on my prop situation. This started out as me trying to help a fellow oso'er with a set-up I was famaliar with. I do have hydrolic steering. It is the imco dual ram assist not full. I could not see how I could fit the helm in the dash thats why I put in just the assist. More looking at props. The mach looks like it is a comprimise between the mercs and hydro's unfortunately I have the xz drive which uses the larger output shaft. Mach never made a prop for the larger shaft, only merc and hydro do. I'll have to take either a merc 28 and cut the blades or a hydro 27 and cup it. Again thanks for your input. Ted dlbcheckmate what types of tabs did you use?. Mine has those cheap dual ram boat leveler that baja and checkmate use. I"m thinking about replacing them this winter and haven't decided on who's the best for the price.

No I didn't buy from Kunkles, I bought it from Franks marine in berlin center. Actually' I technically did buy from Kunkles. One year frank and kunkles went together for the first of the year opening order from checkmate. The paperwork I had to take to the title bureau showed it was bought from kunkles, but it actually was from Franks. I've bought 3 new checkmates from Franks but unfortunately he is nolonger a checkmate dealer. I've tried just about every prop frank has in stock but I am limited because of the large outpup shaft of the xz. Frank had a 253 with a Paul phaff 572 420 mega blower that hit 103. Mine scares me at 80 couple.

Ted, I have the Bennet tabs (twin ram 12x16) I have considered installing K-Planes but I'd rather spend the money on motor parts. I would like to try an Imco "short" lower I think that will give me more speed, but some say that it's not as stable ? Any body have any experiance with a 251 with a short lower ??

Don't do the shorty drive. Mine was ordered with a one half inch higher than Checkmate normally uses. I 'm not sure but I think Checkmate uses a 2 inch higher X dimension than merc recomends. Mine is heart throbling unstable at speed. Think stock. Remember think stock. did I mention think stock.

Ted,

I definitely would not go the route of the shortened drive. This could cause all kinds of stability issues. dlbcheckmate was on track when he suggested installing full hydraulic steering. It was night and day on mine. I would also forgo the idea of changing your tabs and instead spend the money on a helm unit. I never used my tabs on my 242, to include when it ran 110mph. Here are a few other suggestions. The reason Mach props work well on checkmates is b/c they have less diameter than hydo's. Less dia will have less paddle wheel effect and make the boat more stable. So you could do one of two things. You could take a Patriot and have the hub cut out of it and then have a larger hub welded in. Or you can take a hydro and cut the dia down to 15 or 14 3/4. By the way, by cutting down the dia, you will be able to get more rpm's out of your motor, which in turn will give you more speed. Of course if you cut down the dia in a hydro, I would have an additional 1" of defuser ring welded in as well. This will help with planning issues. As for Patriot, I have two that I would let go. One is a 14 3/4 x 26, and the other is 15 x 29. One last question. Have you had the bottom of the boat checked or blueprinted. If you have a serious hook, it could cause some of your problems. Hopefully this will help.

Without full hydraulic steering you are wasting your time. 80+mph without full hydraulic will cause all kinds of handling problems and is simply not safe. Don't waste your money on anything else until you solve the steering issue.

We're not discussing a steering issue we're discussing a handling issue at speeds, with different props. Mercs cause chine walk; Hyro's can't get on plane.

Ted
 

Do you get out to Berlin Lake by Franks much? I do most of my boating out there. I have had Frank to work on my Checkmate. What graphics to you have on your 253? Here is a photo of the tabs Frank put on my last boat.

here is another

Ted-

I have gone through what you are describing in detail for the last 2 years. I still believe you have a steering issue. Yes, Merc props can cause more chine walk , but that is because they usually produce more bow lift.

My old persuader ran about 80 with a Hydro prop, if I put on a merc I couldn't control it past 77. Then I went to full hydraulic and put the merc mirage back on. Instantly I could hold it WOT and hit 83.

My new ZT260 will run 90 with almost any prop. No chine walk at all, but it also has full hydraulic steering. The X dimension is at 17 3/4 which runs fast, but planned poorly so I drop it an inch and lost no speed but fixed the planning issue.

Obviously your setup may vary, but stability equals top speed for most boats. Checkmates are very finicky when it comes to bow lift, prop selection, and steering.

zt260, what prop and HP are you running to hit 90 ?

Its a mirage plus labbed to 24 by merc. I'm pushing 800+HP. But that was last year, This year we are building for close to 1000HP and 100+mph. Once I get the specifics of I plan to build together I will post it for some technical help.

dmann did you have a problem with your right tab and you had to take it to Franks. I was working on my boat at Franks, somebody showed with a boat that has your same color graphics and I helped Frank fix the right cylinder. I do very little boating on berlin. I keep mine rack stored in the flats. Berlin is about a hour and fifteen minutes from my house so it is not convenient. OK i'll convess if you're famaliar with franks I'm the one that went through four motors in one year. Don't ask, three were blower motors. And yes with a lot of work you can fit a blower under the hatch of a 259. You might be right on the chine walking caused by the hydrolic assist insted of the full hydrolic. How did you fit it under the dash. I think the first boat Checkmate ever put full hydrolic steering in was Franks 253 and frank had to do some of the work on it at the factory. They cut a lot out of the way but when the boat is in two halves it's pretty easy compared to already completed.

ted
 

yes, I did have a problem with the right tab. It was from the improper install. If you notice they also put the tabs on the wrong side, L to R. He called me after he drilled the transom and said he could not fit the second ram on the right side.:mad: I remember talking to you now. I think you bought the green & yellow new 259 he had there. I think that was the last Checkmate he sold from his marina.

If you every get out this way look me up. Where do you boat at?

Thats my boat. dmann You're from North Canton, where the hell is that?. Sounds like a third world country. I worked in North Canton (green township) for a few years. Met my wife there. Lived in malvern, on lake mohawk. Now I 'm in Cleveland and keep the boat racked stored in the flats. Thread sealant was put on the wrong end of your tab cylinder hydrolic line. A small piece wedged in the cylinder and that tab was really slow. Good memerory huh? . Let me know if you you do any boating on Lake Erie and we'll get together this spring. My boat is now parked at franks shop. Later in January were going to do a couple more changes to it.

Ted,

You will be amazed at difference between hydr assist and full. When I first started to do motor upgrades on my 242 I only had hydr assist. The first motor was a 454 with a 177 blower, cam and head work. The motor dyno'd right at 600hp. At that time the best I could do was 78.9mph on the GPS. The boat wanted to chine walk and b/c you normally have at east a 1/2" to a full 1" play in the steering cable the problem never got any better. When I went to my 540ci, I also went to full hydl steering. With new motor and steering the boat was more stable at 90 and 100+mph, than previously at 78mph. Again I also found that a little less dia prop makes a big difference. As I stated in previous postings, with less dia the boat handled better and got me more rpm's, thus more speed (ultimately 110mph!). Good luck.

Checkmate110 I'm very interested in the 15x29 prop. Will it fit the larger output shaft of the xz drive? I had a 242 with with a 454 and a procharger, never had a chine walking problem but the boat loved to get airborne. Get back to me on that prop

ted
 

I do get to the Flats a few times a year. What are the changes you are going to do?