ya think 150 rpm will do it?

[Ray Zuelke]

Last summer I went to a Trophy Plus 27 p. Boat ran 82 mph on the speedo -- no gps at that time, estimate 78mph gps from prior test.
RPM was 5800 - engine max wot is 6000. Additionally, I had to trim positive to get too 5800. I felt positive trim added to chine walk condition. Can drive "through" it, but difficult and interesting.

I thought if I had the prop worked, asking for 150 more rpm without needing so much trim, would be better.

With that in mind, I delivered the prop to Merc Racing in Fond du Lac. GREAT EXPERIENCE. Excellent customer service. Scott @ Merc. said he would do a partial lab, "wedge" the leading edge and take some cup out of the back end of the blade. Done. Looks great, can't wait till spring to give it a run. I now have a gps - Garmin 276c - which I will install before ice out. I will report findings. Merc. said if they did not hit the bulls eye, bring it back and they would work with me to further dial in. Great.

I would appreciate any in put on my process so far----have a little time to gather information, still driving on lake with atv at this time.

Z

 

[JW]

You asked for more rpm, but that's not always the best for our type of boat. We can use the 'cup', which helps bow-lift.

All that being said, if you told him what type of hull and engine the prop is for, then you're probably good. The better prop guys know what a prop needs to work with certain hulls for better top speed. Did you describe the boat and engine package to him when you sent the prop out?

 

[Ray Zuelke]

I hope I didn't screw up. I guess I knew in the back of my mind that the cup helps with bow lift, which gets air under the boat, which makes it fly. When I talked with Merc, I told him in my opinion 150 rpm would give me the 2 mph I was looking for, while being able to accompolish that with less trim, which should cut down on chine walk.

I did share the yr. make, model of boat. He seemed quite familiar with Checkmate. He even shared in a prior life he had quite a bit of time in a similar hull--- some type of bass boat. He was very familiar with the engine, Merc's 250 Pro XS.

After I got the prop home and started thinking --- I thought it would be a good idea to get in put from this site.

No matter what, all is not lost. If I need cup put back in, another trip to Merc will get that done. Thing is, I don't mind giving up my #1 prop in the winter. Same would suck in summer. Very short in N. Wisconsin.

Thanks for your input.

Z

 

[hotdaddy27]

In my opinion, chine walk will always be there with a Pulsare 2100 over 70mph. I would spend more time behind the wheel before I messed with set-up as an attempt to alleviate the chine walk.

Last year, I 'bout scared the hell out of myself trying to "tame the walk", but eventually I got the hang of it and now counter-acting it comes almost second nature.

I am no better a driver than the next guy, but I kept the setup where it was until I could control the boat. Then I tweaked and twisted for speed (still looking for it mid 80's and climbing)


Good luck!

Oh yeah, the chine walk seems to be worse with the heavier 3L motors.

HD

 

[Mark]

Should be an interesting experiment one way or another. Typically, the cup provides the grip, the rake provides the lift. But they work together. As JW says, if you lose too much grip then the prop lets go and the bow comes down. Usually the more the cup, the higher you can raise the engine. However, it is all a delicate balance. You'll find out in the spring if they nailed it or not.

 

[smallblockford]

i think the guys at merc will have you pretty close labing a prop is pretty neat the right guy labing your prop can make the world move a little bit faster in your boat. with out even cracking the moter apart

only time and testing will tell keep us informed on how it turns out

 

[hotbeek]

Hey Ray,

I think your prop will probably work for you. I think you could get some more with setback and height adjustments. You'll get less walk with a higher propshaft dimension too.

Better keep that prop off the bottom of the Lake.

P.S. You'll love that Garmin 276c. It works great on the fourwheeler too. I had mine mounted on my snowmobile this winter. Better than most snowmobile maps !

 

[Roberts Marine]

Hey Ray, just happened across your page. Who ever wrote that the chine walk doesn't go away on a 2100 is correct. It is something you have to learn to balance. To get the boat to go fast you have to reduce the wetted ares of the bottom. ( Less Friction) The fewer degrees of trim required to air out the boat the straighter it is being pushed through the water will help reduce the walk. That is one reason for the increased set back on the transom. I believe we have a 10" plate on your boat. If it is the 5" a 10 will help. Now that the boat is aired out you are running on a very small surface in the water. You also have a large prop turnig to the right which in turn is trying to twist your boat to the left. It would be like tring to ride a bike with a large weight hanging 5" off to the left. You cuold do it but learning to balance it would be a whole new trip. So you just need some seat time untill you get the feel of counteracting the boat coming off balance before it actually tips to one side or the other. Once it starts bouncing back and forth you just got to start over. Let me know how the rework from Merc works. I'm still looking for the perfect prop for the 2100 too. The lab finish Bravo 4 blades are pretty cool. Lots of money.
Bob