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.