Rage - Chine Walking & Trailer Q's
 

Hello there!

I've got a new to me 2001 Rage with 90 hours. I've done the following:
1. added a procharger, new gaskets, Imco Powerflow & SS pipes; AZ S&M recalibrated the ECU.
2. New XR drive and added Mayfair one-armed steering.

The blower is making about 4psi. I am running a Bravo 30".

I haven't been able to really get into the top end, only turning 5,000 RPM (rev limit is now 5,400). Trouble is the boat starts getting squirley at about 80+ mph, chine walking back and forth fairly violently.

Any thoughts? Can I drive through that speed and get it to smooth out? Do I need tabs? Has anyone worked through this.

SECOND question -
I am in Seattle - my trailer is shot. Any thoughts on replacing the trailer?

There's a few here running 90+ that will chime in. I haven't heard to much about chine walk but I could be wrong.
Dave

I think bobl can talk about chine walk in the mid 90's with TX_Instigators Rage (I think he backed out and wasn't able to take it all the way) , but they also found it settled down quite a bit in the low 90's with some weight in the boat.

I've been messing around with my heat with gear ratio's and props. The boat was chine walking pretty bad at one point. Sent the prop out to be labbed. The diffuser ring was cut off and the boat really settled down tremendously. Only problem is if it don't work you just trashed a prop. Are you willing to experiment - $$$. Just my .02

A v bottom going fast is a balancing act. Many factors play a part. Different props will make it do different things better. tabs will help but in the end you'll have to drive it. Anticipate as it falls to one side or they other. As it falls to a side twitch [ snap and return ] the stern over that way and balance it so that it doesn't fall. When it falls and hits it will bounce to the other side and progressively hit harder and harder. The trick is to catch it and not let it hit at all. I would suggest practice balancing in a lonely area slightly over trimmed to make the bow light and practice balancing it AT ABOUT 75 % THROTTLE.Wear your kill switch. I learned how to fly a STV with a EFI 450 lb 100mph boat. Once you learn to anticipate what it is going to do you can DRIVE thru it and as it begins to fly it will smooth out. BE CAREFUL AND DON'T BACK OUT OF IT TOO FAST. Maybe this will help. My 3 cents , Jim

Thank you all for the thoughts. It's pretty snappy side to side - a little scary. Will practice a little bow light at lower speed.

Anyone put tabs on to correct it?

Interesting to think about the diffuser option. I do need to get the prop worked over and could do the diffuser.

Thanks again- Collin

Tabs make a good boat better and will give you more control of the boat in every situation. Get a good set like K planes. I never heard anybody regret buying a good set of tabs.
Jim

Was cutting the diffuser off recommended to you as a fix for chine walking?

Any negative effects from cutting the diffuser ring off?

Raytart - I am interested too in hearing more about the impact of the diffuser ring removal - is that on a B1 4blade?

ALSO - Anyone have problems with blisters/gel chips on your hull? I just got a steep quote from my marina in Seattle to fix some problems (prior owner banged the step on the trailer fenders, blisters along the chines on both port and stbd). Does Nordic have a hull warranty?

Thanks!

My rage is doing the same at a little over 70 wit the tabs up. If i bring my tabs down just a little, about level with the bottom of the boat it levels out. Glad to know it's not just my boat, I am not experianced enough to know how my boat sould act just yet.

While I am at it, I need some input. I have a 540 with a Vortech J series supercharger, Bravo 1 that was rebuilt to an XR by Max Machine, and a 30 pitch prop. Mark Boos at Presicion Marine Dyno'd it at 672hp @ 5400 rpm's. I can only get 4800 rpm's (my gauge says 5000 but the computer said 4800) and 75 mph out of the boat right now. Seems to me i should be running faster than that, my friends stock 496 runs over 70. Should I try a 28 pitch and pick up the rpms? I like the way my boat runs and my fuel econemy is great in the midrange but something just doesn't seem right?

Boost builds with RPM (particulary with centrifugal superchargers), and speed comes with boost and RPM. You probably aren't getting much boost @4800RPM. Try the 28. My boat is as fast or faster with a
28" P5-X as it is with a 32" B1, because I can spin it faster (+400 to 500RPM).
Regards,
Steve

I have the boost set @ 4 lbs. I am getting 627 hp @ 4800 rpms. I didn't want to increase the boost because I run the boat every Sunday with the family and wanted to keep it somewhat reliable.

I can concur with the previous comments that the Rage is prone to chine walk approaching 80 trimed out and once you get the hang of it you can generally keep the hull balanced enough to keep it from getting extreme. This is true for relatively consistent water taking waves head on or going away. Cross waves all bets off. I have the IMCO single ram external steering. Some times additional trim out helps stability in this mph range as well.

Rocket Man ran, I believe it was, 107 mph in a Rage on nitros a while back at a west coast shoot out. When I asked, he advised that as long as he was accellerating the handeling was ok but got squirley when shutting down above mid 80's or so. I believe his comments was regarding a straight line run only.

As also mentioned speed reduction should be cautious when in the 80's range and above as well as trim reduction.

I assume your motor is a 496? If yes do you still have the stock 496cast aluminum pistons in your current set up?

Here are a few photos
Pics 1 & 2 are the new 26 pitch prop that was labbed (Thinned out blades and diffuser ring cut down) It was cut down to be even with the back of the prop shaft.

Pic 3 is my old prop. Notice the length of the diffuser compared to the 1st two photos.

Like I said earlier... I changed my gear ratio from 1.50 to 1.36 as an expriment in hopes of gaining top end. The orig. setup was spinning a 28 pitch bravo to approx. 5300. With the 1.36 gears I couldn't spin that prop. So... I got a stock 26 which I could only get to about 4500 rpm. The speed was almost the same as the orig set-up but the boat was chine walking bad especially when coming off a full speed run. I had TSPM send the prop to his prop guy and he thinned the blades to pick up rpm and cut the diffusser to help the handling issues. Not sure why he thought it would work but I agreed to let him do it. Well IT WORKED PRETTY DAMN GOOD. I still need about 200-300 rpm so I'll be sending it back. I also took the drive spacer out prior to labbing the prop in hopes of that helping the chine walking but it made no differance so I put it back in because I had positive results with it when I first installed it. Am I making sense???


And Yes - it's a B1 4 Blade!

With the IMCO exhaust and ASM recal I would guess NOT a 496 :cool-smiley-011:

raytart,

I am really interested in this chine walking versus prop mods you experienced. I hope you do not mind a few more questions.

Did you experience the same chine walking with the stock 28P B1 and 1.50 gears that I believe you said produced the same mph?

Since the chine walking with the 26P B1 and the 1.36 gears went away when you had it both labbed and the diffuser ring removed how do you know that the labbing alone could not have been the reason that the chine walking was eliminated?

Did the prop shop mention fixing any other chine walking problems by diffuser ring removal only or other experiences that lead then to the conclusion that diffuser ring removal is the key to eliminated chine walking.

Do you have the number for this prop shop?

Hey Rage

Not a problem answering your questions.

The answer to your first question is NO. No problems prior to gear change.

As far as the labbing of the prop eliminating the chine walking... I really can't give an answer on that because the labbing and the cutting the diffuser were done at the same time. I never spoke directly to the prop guy. I spoke with my dealer (TSPM) and he relayed the message to me. But I recall the conversation and the prop guy told him that cutting the diffuser would help with the handling issues. I'm not even sure of the prop shop or the guys name. Have you asked this question under prop forum? I read some of the posts and there seems to be alot of knowledge there. You may find someone who has done this before and possibly get a more informed answer. Keep in mind that with the gear change, the prop shaft is actually spinning faster but the motor is not. I tried other props with the new gear change and did not experience chine walk. But those props, all of which were B1 4 blades did not allow me to get even close to max rpm.

Like I said in an earlier post "Are you willing to expriment...$$$. I was and I'm still experimenting. I still need a few hundred more rpm's and I hope to get over 80 mph. If I don't get over 80, All of this is one for the books. But I must say that I did loose "Punch" But not too bad. I do like the way the boat carries itself now. It feels like it's riding higher out of the water and the sensation of flying reminds me of driving my old Hydrostream.

Ray

Thanks raytart. I will check and see what the prop forum has to say.

I had a 700hp Rage that walked between 80 and 90 mph.
Didn't own it long enough to really figure out a cure.

Now I own a 35 that walks near 90. Just add in a little tab
and it's solid. My solution on the 35 is live with the tab since
the boats fast enough that I don't care for any more.

Further down there is a thread asking about blueprinting hulls.
I've been intrigued by the following possibility:
There is no such thing as a flat fiberglass surface, in order to give it strength (Orval Summerstedt taught me that). Put a straightedge on your chine and notice that it is convex.
Now take the convex side of a spoon and hold it against a stream of water, and it will bounce on and off in a way that
makes you think of chine walking. I wonder if a good glass guy
could bondo (this would preserve the inherent strength providing shape of the glass) the shape of a chine to be exactly flat, and if that would cure chine walk?

I'm definitely not a glass guy so don't blame me if I'm
full of it.

Pesky Varmint

Peski Varmit,

Very interesting experiences you describe. I have not played with the tabs yet for chine walking control thinking they would just slow me down. But there may be a fine line of just enough tabs to steady things down but not scrub off speed. Worth some testing. The concave hull theory as to contributing to chine walking is interesting as well. I was thinking more on the lines that hull irregularities will cause parasitic drag. I wanted to hear from someone who has blue printed a Rage hull for actual before and after results.

Rage

Check your post in prop section. There is somewhat of an answer to your question.

Ray

raytart, I saw it. I posted a followup question asking about any negatives to diffuser ring removal as well. If nothing significant I will likely have the DR removed to improve the basics of my set up. Thanks.

raytart,

Feedback from the prop forum (below) says there may be a penality to removing the diffuser ring in the form of plane out problems and less bow lift. Did you see that?

throttleup
Throttle Up Propellers
Platinum Member
Join Date: Mar 2002
Location: St. Petersburg, FL
Posts: 3,955 Quote:
Originally Posted by Griff
Maybe a few more rpms (50-100) and a very small speed increase. removing them may cause problems getting on plane and reduces bow lift.

That has been our experience as well on stern drive applications.

Julie
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raytart,

The prop forum was informative on this issue.

There was mentioned a potential down side to diffuser ring removal. That was increased potential for creating control / handeling problems do to prop ventilation during plane out, in turns and reduced bow lift. Any of these things happen to your boat?

Nope,

Very happy with the results I got.
Just cut the damn thing off already!
What's the worst that can happen?
You won't know till you try it.
Why don't you keep the prop you already have and don't mess with it. Then buy another prop (possibly used) and have that worked. This way you won't have any downtime while it's being labbed. AND you'll have a spare prop.

Ray

Thanks for the info.