How high to fly the bow on a tunnel?

[vishus]

does anyone have pictures of how they fly the bow on a tunnel (RapidCraft RIOT or STV EURO) to get over the "hump"? I am stuck and can't get my RIOT past 85 (with some weight in the boat) or 79 with me and a couple of gallons of gas!!

I spoke at length yesterday with UT, he is a WEALTH of knowledge on the 2.5EFI, and sounds like a good tunnel driver as well.

I just want to see "what" it looks like!

thanks,
sid

[Gordie Miller]

OOOOOOOOOOOOOOOOOOOOHHHHHHHHHHHH, this is a trick question. The answers should be good.

[vishus]

no trick that I am aware of. I just haven't been able to do it. I have the motor running well, and I am now working on learning to drive it. I only get a small window with good water and no traffic to practice. With a couple of hours of trying, I can't fly it (YET)!


thx.sid

[LaveyT]

I have seen the Riot flying mighty high! I run my Lavey at a pretty extreem angle and his was just as high.I think Anthony SS wrote an article on the STV owners site about this subject also.
As for the Lavey,it takes a bunch of trim 3/4 out or more on the gage to get full lift (unglue the bow) then I trim it in slightly and I can feel the stern "pop" up and full speed is achieved.I am still working on weight distribution/setback to improve lift/speed.
where a good jacket! Dave
Also,I noticed that when I have a 220 plus passenger in front to avoid hop I must sneek up on the trim as the speed builds.If I just trim up and nail it the hopping will not stop at 80mph:eek: Scary

[Sam Baker]

We've had this discussion several times actually. With the riot - as well as STVs - you need to fly them higher in the midrange (50-75). Then trim down at about 80 to level them out. Once you reach those speeds, there is enough air pressure to hold them up at a more level plane than when they're running 55-70. I know when I drove my Riot, you could trim the thing to stupid angles at 55 and it would just float awesome. Then you obviously have to remember to trim it down as you go faster so it lays down flat and goes fast.

I just saw Kirk drive his last night and he looked great. He could've tapped her down a notch or two, but he didn't have it too terribly high. They do run pretty level at top end.

Unfortunately, I don't have any photos of me running my Riot at high speed.

sam

[woodco]

All Ya Need Is ..........

[Talon2.5]

hehehe woodco, the only flying youll do with that is back to get it re-sleeved hehehe

had alot better luck with the mercs than my freinds with those and thats a fact jack!!

sam pretty much said it all right there!!

[vishus]

thanks for the replys. I understand what I need to do, I was just hoping to see what it looks like. My brain and my trim finger are fighting me on this one.


I am going to go out next week during the week with a friend and his EURO. Hopefully we can practice to get this right.

how long did it take for most of you to learn to drive these tunnels?

great pics lavey...

thx.sid

[Ted Fraser]

sid , I had the same problem a few years ago. I bought Kirks boat with a 2.4 efi and I went to Ron Baker to pick it up. When I tried to drive it it would be everywhere at 65 to75 mph. It would hook back and forth and I would have to let out of it. The best way I found is to trim it up and nail the throttle and speed increases trim down and the transom will lift and you will be on the pad. I ran a cleaver and it seems to help in bringing to transom up. The boat ran 103 with a 30 inch prop and it was surprising good it a chop about 12 inch is what it like but it will handle rough water pretty good. It was a lot of fun to drive and was very fast. I bought a nitrous kit from Chuch Goodman and ran it for a while and I did not get beat to often on the lake. This is what I run now.

[STV_Keith]

Not a Euro, but I've found in the limited time with my '92 Pro Comp Ski that I do trim it more when cruising in the middle, just to keep the bow hung and it smooths the ride a little.

I trim it about level before I go for a blast over 70mph, which is where mine starts the porpoising with 2 people in the front seats. That stops around 83-85mph and the boat settles fairly flat.

My motor still has a rev limiter stopping me at 7000 (well, I have seen 7100 on the tach - however accurate that is), so I tend to hit the wall then trim it up to see if flying it gets me any more speed. Here's a pic of it trimmed flat, at around 97mph (all I can get with the limiter in place)

http://www.speedcraving.com/stv/misc/keith-7a.jpg

Now, here's the next pass, trimming more to see if flying it a bit higher would help the terminal velocity (it didn't).

http://www.speedcraving.com/stv/misc/keith-6a.jpg
http://www.speedcraving.com/stv/misc/keith-5a.jpg

[BLACKBIRD]

telling someone how to drive a high performance boat isn't the most simple thing to do.If you think it can be done by reading a description or something like a how-to manual this is a scary way to learn. You have to get the "feel" of the boat no matter what hull style and getting the "feel" can be somewhat frustrating to some. Once you get the "feel" it's like riding a bike,,, you never realy forget it, or what it feels like.

I would STRONGLY recommend that you do NOT use written instructions or pictures to learn such a "instinct " type skill. looking at pics would only be a good comparison if you could ride outside and look at the boat's attitude at the same time while sitting in the drivers seat and accuiring the "feel".

Get some you trust and has experience with high performance boats. Ride in the passenger seat and "feel" what going on. Talk to him about trim angles and maybe have him give you a thumbs up when he feels the boat is trimmed correctly. Then you take the wheel while he sits as passenger and be prepared for him to say STOP or TRIM DOWN or even TRIM UP.

Get the "feel" the smart way. Swimming is what you do after the boat ride to calm the excitment;) ;)

[KaptainKirk]

You bought my boat??
Or do you mean when you bought a Riot like mine ??
Vishus keep practicing it will come.
It just came to me when I was running around with Bruce Bush and Yammer in Ohio.
Since then I can get over the hump at 70 with ease.
Once in awhile with 2 people 25 gals gas and cooler full I have a problem for a burst then get out of it , hit it again and I am over the hill.
Most of the time now it is second nature done with out thinking.......but it was a bitch at first and I was scared like we talked on the phone.
There is a guy named Whitey in Ohio who has Bakers personal Riot.
He doesn't like the cleavers on the Riot.
So far I like my 28 cleaver no matter what the load...even dusted a 260hp riverrocket he had two guys and was runnin a 26" I had me and my lady inda boat and I was pulling him at a little over 90.
I also like the yama drag props....but they don't like 3 people in the boat found that out last night had ta give her 8500 on the way home ta fly the 3' rollers onda way to the launch ramp.
Of course that was 20" pitch yama drag prop.
Keep testing it will happen.
Also are you running outa HP ??
I been to a 104.6 for a best so far.
Been between 101 and 103 a whole bunch.
Also I have added the Johnson brothers fin.
It has helped tremendously with holeshot!!
Keep us posted on your testing.
K.K.

[Gordie Miller]

This is mostly a racing scenario, but to a certain extent it will hold true in pleasure applications too. " There are two kinds of tunnel boats drivers.........................those that have blown over, and those who are going to blow over". Marles???????????? Am I lying here?

[B.Leonard]

Full tunnels that is :D

-BL

[mr fun]

but my wheel torques right and i gott crank it left, if you look at that shot of Lloyd on the Carrolton advertises thread so does he, but you are crankin the wheel right? is that a left hand rotation motor? :confused: fun out.

[us1]

How true it is. In racing if you don't blow it over you aren’t pushing it hard enough. Blackbird said it all; it’s all in the feeling. In certain conditions you can stand it up on the tail all the way down the lake and in other conditions you need to tuck it under and pick up the tail keeping the nose down. If you try to drive it at one certain angle it going over for sure.

[us1]

By the way, never drive at this angle, right Gordie.

[B.Leonard]

That shot was a gradual right hand turn at about 65-70mph.

The boat has almost zero torque steer. It does have a torque tab on the skeg. Also, I'm finding out that even though my propshaft is 1" above the sponson pads, due to it not having a center pod, the motor needs to come up much more.

-BL

[Racemore]

I don't care what kind of boat it is I fly a tunnel to the edge or as high as It will go with out going over.When the boat is trimed up and the bow is lifting into chine walk is race trim or bleeding it.If you have enough power to reach this point then getting over the hump isn't a problem so you run just under it and the faster you go you can drop the nose but never to the point that it sticks or drags the nose down.Once you find that range and can maintain it in variable conditions you will have the answer to your question.If you can't get to that point setback, prop tuning and type can help.If you still cant get there you need HP.

Ted,you may have to much stern lift with three cleavers.you might try a round ear on the center motor since it is in dirty water.I know it might sound strange but i loaned my 34 Hoss to a guy that had twin V8's on a 30' Chris Cat because he tore up is standard rotating cleaver which was a 30 and he ran 3-4mph faster and said it freed the boat up.Strange but true.You can tune a cleaver to have bow lift also.Ugene at REMCO prop ran King of the hill at 117mph on a Valero YT in 1989 with a Cleaver.

Just a thought.:cool:

[us1]

That’s right full tunnels can go much higher. The Silverwing is 3 inches above the bottom and my Sterling is 4 inches above the bottom.

[LaveyT]

Bruce,You will pick up a few MPH if ya SIT DOWN when driving.
Hate ta burst your bubble but ya look like a Tim Conway tape I got,Dorf drives tunnel boat:p

[B.Leonard]

It's a habit I got from the Lund :D

No seriously :D ... it's a very skinny boat, I've been thinking about a windsheild, something to give it some thickness, but all that wind in your face sure makes it fun :)

-BL

[WILDMAN]

Trimmed up looks good, but mine runs fastest perfectly flat. Looks like the whole boats touching the water. Fastest yet is 124 on gps turning 32's at 8300! I run my motors in the tunnels and they're 5 inches above the bottom! Of course there is no water pressure over 95 mph so I use a transom mounted water pickup. It's only 1/8th inch in the water, but feeds both motors at 15-20 lbs.

[LaveyT]

I know this is off the subject a little,but: As B.L. states his lower
should surface,But there is no pad to measure from.On a MOD V.P. boat the center pod pushes water down (more or less) and controls the water feeding to the prop at a fixed depth in most water conditions.
On a true tunnel the prop/lower would see more variations in water flow?In a six inch chop lets say,wouldnt the prop/lower see it? How does this effect blow out, handling ect?:confused:

[Stray Kat]

VISHUS

What props are you running? I bought my RIOT new in 1997 and ran 27" & 29" MAZCO RE3's. I always felt that these were not the right props for the boat even though the boat ran well.
It would run over 100 MPH with either prop but I had to work at it and needed enough room to do it. After seeing a lengthy video of my boat last year I finally got to see how high it flew & it was definately too high. I bought a 3 Blade 28" MERC LAB Cleaver and a 4 Blade 26" Hump back Cleaver over the winter. What a differance in the handling of the boat. With the 4 Blade 26" the boat runs a solid 100 MPH with a full gas tank ( 35 gallons ), one passenger, cooler & other boating stuff - even as the gas goes down the speed stays right at 100 MPH. However with the
3 Blade 28" Cleaver the boat runs 103 - 105 MPH after burning off about 10 gallons of gas. I've run 107 MPH alone in the boat
may have gotten more speed but ran out of room. The boat handles better than ever before & runs nice & flat with a good cushion of air under it. Once you get the feel for the boat & how to drive it you probably need to do some prop testing to find the prop best suited for your rig. :D ;)

[gtsmpuc]

This is waht it's all about.