Which prop is better?

[Dhadley]

Re: Which prop is better?

Glad you got the Pro set up. You might think about the other hoses at some point.<br /><br />With the steering torque you had in the other boats you know what we mean. That's a classic case of the gearcase not being set up properly. While I wouldn't let go of the wheel at 65, there shouldn't be any pull in it at speed.<br /><br />With the hydraulic its still there, you just cant feel it. The only way we know its there is by the fact its harder to turn in one direction. <br /><br />This is why it worries me when folks talk about going to hydraulic to "eliminate steering torque". Hydraulic steering doesnt eliminate it, it hides it. Thats why dual cable is the much prefered set up on fast boats. And not the "no feedback" systems either. We want the feedback. That tells us if the motor is straight or not.<br /><br />Anyway, we hope you get to test soon. We're all anxious to hear how youre coming along.

 

[brownies]

Re: Which prop is better?

Back with test results and a new theory for speed.<br />Test conditions were not just great. Gusty windy. Considered this about normal though since very few days are just "perfect".<br /> Before modifications, WOT, 59mph/5000rpm, stable, drivable, propshaft 5" below pad,25p prop, hydrofoil.<br /> After modifications, WOT, 62mph/5400rpm, unstable, undriveable, propshaft 5" below pad, 25p prop, no hydrofoil.<br /> "PROGRESSIVELY" better by raising the motor as far as I could without unbolting the motor and raising it on the jackplate. <br /> BEST at WOT, 1.5" below pad, 65mph/5600rpm, unstable, undriveable, 25p, no hydrofoil.<br /><br /> BEST DRIVEABLE, 60-62mph, combination of backing off the throttle and/or trimming down thus increasing the contact patch, 1.5" below pad.<br /><br /> I think I have found a point where the boat will run with stability. If I trim up a shade, it will Decrease that contact patch and things get wild, in a hurry.<br /><br /> I would assume that most 80mph bass boats have these same constraints, and, that they are probably running "stable" on a larger contact patch than what "could" be had. (they could go a couple mph faster by trimming up, but, would be unstable like my boat?).<br /> <br /> I'm now thinking that I just may not have the power to push my boat faster on a larger contact patch?<br /> Does that make any sense, or, do I need to keep adjusting?

 

[walleyehed]

Re: Which prop is better?

DH, I have to ask...would the over-all lift of a TXP "possibly" help control some chine-walk?????<br />Remember me telling you it had a "feeling", not bad, just different???<br />I don't have a pad, but in my head, I see the over-all lift as a stabilizer "On" the pad.<br />I guess I'm wondering if there is too much bow-lift causing the boat to roll to one side when up and relatively "clean"...falling to one side or the other is causing the start of the chine-walking...???? (just thinking out-loud here).<br />I may be way off base here...

 

[brownies]

Re: Which prop is better?

Dhadley and Walleyhed, <br /> I sure need a direction here. Before messing with it I had a stable 59mph ride at 5000rpm WOT and propshaft 4.5" below the pad.<br /> Now, $2500 later I have a semi stable/controlable ride at 61mph at 5300rpm and propshaft 1.5" below pad (wooo....sigh). <br />I trim it out some more, bow climbs up up up and I've seen 65/5600 once and it wasn't a pretty sight.<br /> The chine walk "rocking back and forth" turns into a "seat of the pants feel" like the boat is almost "circling". That's when I shut it down.<br /> At that point, am I running on not enough pad? OR is that even possible?

 

[Dhadley]

Re: Which prop is better?

When I lost the computer server this morning here's where I was at --<br /><br />I think youre both onto whats going on. Yes, at this attitude with this prop we're going to need more torque to go faster (on the same pad area). Yes, if we start using different props to get a different ride attitude we may get past that. <br /><br />We're also getting into the area where we should look at the design of the hull. The pad should be perfectly straight. The edges should be sharp, especially the back of the pad. As you go out from the pad there should be a slight hook. The further you go out, the more pronounced the hook. Hook gets you on plane. Once on plane and on the pad there should be no hook in the water. <br /><br />I think youre going in the right direction. Every time you raise the motor it gets better. I mount my motors on the plate as high as they will go and then run the plate lower. If you need more height, that will give you the most. <br /><br />Youve made real good progress with your rpm. You went from a 2:1 gear ratio and 5000 rpm to the 1.86:1 lower and 5600 rpm. With the same prop. Gaining that much rpm is a real feat but gaining that much AND going to a 1.86 ratio is great.<br /><br />Lets do this -- you have a comfortable spot now. At that same (comfortable) spot lets try some different props. That will give you the feel of what different styles do.<br /><br />Do you have any buddies that we can use their props?

 

[brownies]

Re: Which prop is better?

Seems I'm the only person I know around here with a yamaha. I have a 25p tempest (and hub kit) on the way. At least if I don't like it, it won't be hard to get rid of.<br /> I almost hate to jump all over the place with blades, brands, manufactureres, styles. <br /> I don't mind trying lots of props, but, think it best to be somewhat organized about it. <br /> For example. Try three or four different pitch Tempests to begin with. Keep the one I like best and then maybe try a different one.<br /> Whatchathink?

 

[walleyehed]

Re: Which prop is better?

I don't feel that just trying one model in different pitches is going to solve any handling issues.<br />I feel you'll find the better handling props by trying several manufacturers in the same pitch...yes, you may find 1 or 2 that give different RPM figures-and this should be expected, but you will likely find the design best suited to your boat quicker.<br />See what DH thinks.....

 

[Dhadley]

Re: Which prop is better?

The Tempest will definately give you a different feel than the Yamaha prop. Personally I like to try different props on the same rig to get the feel for each. Each one will have strong points and be better suited for certain things. I hate to limit myself to one brand / style with any given hull and set up.<br /><br />Remember, the faster you go the hydraulic steering is going to be one of the major factors in how the boat handles.

 

[Ron G]

Re: Which prop is better?

Just going to say this is a very good thread,out of curiosity im amuming the hydrolic sterring is not letting him drive the boat is this correct?

 

[Dhadley]

Re: Which prop is better?

Lets just say it's something that needs to be kept in mind. There's always some slack in a hydraulic system. That may or may not be an issue when youre trying to balance a boat on the pad. Driving at these speeds and above requires some small constant moving of the wheel to counter the chine walk. The faster you go the more precise those movements, or corrections, have to be.<br /><br />Any steering system - any system - that has slack makes it easier to get "behind" in the steering. As the boat starts to walk over to one side you steer the other way. The boat then comes back and you counter that. If you get too far behind you'll be steering the same direction the boat is trying to walk or dip.<br /><br />Many times we can correct it all with set up. Sometimes not. Making a prop change can help or it might be more pronounced. Thats where all the testing comes in.<br /><br />Some pad bottom boats are easier to drive than others. Some take a very skilled driver to control. Some may not be able to be controlled above a given speed. It all has to do with design.

 

[walleyehed]

Re: Which prop is better?

Ron, It's an issue of "less" feedback. Makes it harder to tell what's taking place back there.<br />As DH said, "it's hiding the true feel".

 

[walleyehed]

Re: Which prop is better?

Sorry DH, I was typing same time as you...

 

[Ron G]

Re: Which prop is better?

Thats what i thought.on mine when it gets up there like that you got feel the motor more than the boat to drive it,makes sence.

 

[brownies]

Re: Which prop is better?

I'll be back with more info from testing IF anybody still wants to hear about this. (it's making me crazy) <br /> I guess I was just nuts to think the following: <br /><br />I thought this boat should easily go considerably faster being from a reputable company that claims to be a leader in "performance bass boats".<br />I thought the speed would be easier to come by and that I would not be having these problems until....around mid 70's /mph.<br />Looks like I thought wrong. Not giving up on it yet though.

 

[walleyehed]

Re: Which prop is better?

Don't give up...I know Dhadley has some tricks up his sleeve, and if ya don't post back, we don't learn either...<br />Looking fwd to your testing.

 

[Dhadley]

Re: Which prop is better?

Yeah, dont give up! We'll get it. I know it's a lot to digest at one time. Thats why we make small changes. Lets see what the Tempest does. I'd love to see what one of these Lightnings or TXP's would do.

 

[jelacop]

Re: Which prop is better?

sounds like you are trying to get orange juice from a lemon.<br />yes the main factors in speed are rpms, prop size, and gear range. but small motors can only turn big props if it has the horsepower to do it.<br />i know you put the kits and did the engine work. but what about compression, fuel, and fire.<br />if you back bore your intakes and exhaust for more efficency and shave your heads down or get a set of 135 heads you will increase your compression to about 165. you will see a dramatic power increase. as for the chime the prop probably is lifting the boat to much because you are sliping the prop to get 5600 rpms right now. two choice are spin a little smaller prop faster or get the power to spin a 27 pitch prop.<br /><br />this formula has worked for me in my need for speed:<br />rpms / gear ratio x prop pitch / 12 x 60 / 5280 x 93% = about your expected mph<br />do the math it works<br />and good luck turning that 150 into a 225.

 

[brownies]

Re: Which prop is better?

Compression is 175psi across the board. <br /> As far as OJ from a Lemon? Do you really think I need a performance rig to catch a fish? Does anybody?<br /> OR, Rather...it hasn't helped me catch a fish. I can, however, NOT catch fish must faster than before.<br /> That's not the point, That's not the question, That's not even an issue.<br /> Trying to get OJ from a Lemon? It's a Given.<br />All Jelacop's thoughts have been considered. <br />The math is no problem. The hp,speed,etc is a problem, but, a minor one.<br /> The real problem I'm having is "no sense in going 80 if the boat won't take it (if it's uncontrollable).<br /><br /> DH and Kenny, others and ANYBODY with some suggestions are giving me some ideas on how to adjust the attitude of the boat via set-up/prop selection in order for it to go faster, more stable. Right now, when things get wild, it seems as if the bow is way up there. I think if it had any more lift it'd fly.<br /> Thinking that a short 17' boat, light in the front, may need to run at an attitude with a bit less lift. I know that means more drag, but, maybe I can stumble onto a prop that will help?<br /><br /> Apolgies also, Most days I really don't make much sense no matter what I say........sigh.<br /><br /> I've learned a some things on this thread and now have an idea of where to go next. (left myself wide open on that one). Anyway, I'll continue looking here daily and hope I get some props in by weekend so I can test, give more input, and maybe get some help in narrowing it down further.

 

[Dhadley]

Re: Which prop is better?

Youre correct in thinking about the lift. At the point youre at we want the prop to lift the boat, not the trim. The prop will have more "straight up" or overall lift where the trim lifts the bow. <br /><br />I vote for leaving the set up where it is now and trying the Trophy. Compare the two and see what you think. I'm thinking you'll think you stepped into a whole different boat.<br /><br />Remember, one change at a time. Youve stuck with your baseline prop and found that there is a comfort zone and a speed increase. Lets leave the set up where it is and change only the prop.

 

[brownies]

Re: Which prop is better?

Would I be considered an idiot of I JUST NOW "got it"? (even if only a little)<br /> Let me make sure.....<br /><br />Lift when referring to a prop raises the back of the boat? (straight up lift on the motor, or, if not straight up, it is upward, at the motor)???<br /> AND...Not the bow rise induced by trimming out?<br /><br />If that is correct, then please scoot over just a bit so that I can get over here and share the same page as you.<br /><br />It's all starting to make more sense now.<br /><br /> (I'll be breaking ice to get out on the lake and try these other props now. My newfound enlightenment has given me some badly needed inspiration).<br /><br />If that's not correct, and I'm still "in the dark"....please wait a few days to tell me. Inspiration to run a boat at WOT in 30 degree weather is hard to find...lol.