Finally....part II

[John Richied]

I gotcha BP, I actually understood you, I was just agreeing in a strange way… LOL
Oh yeah, I like the 'zen part too. :wink:

Now hanging off the back of the transom… damn…. Okay I have done it before too, but just to see how much water was hitting my foil off the prop. If you could get someone with a video camera and a fast boat to film your gearcase, pad, prop at 90 plus mph that would be way cool.

Scott (Yeller) had some video footage at the Allison Rally back in 2003 of a guy breaking in his 300 Merc drag, A bunch of them were on a run and it looked neat as hell… The guy was filming the prop and gearcase and the guy driving the boat with the 300 drag stabbed the throttle… WAY COOL! :mrgreen: :mrgreen: :mrgreen:

 

[GPI Racing]

Well, here goes,

The reason I do this(look over the back) is no matter how much you measure the pad (or bottom on a tunnel-vee) in relation to the gearcase or propshaft, in all my years I have never, ever had the water flow end up where the straight edge pointed it would. Depending on the boat's angle of attack (and on an Allison the size and shape of the lip) the water will rise at some form of angle. The weight of the boat, width of the pad, and speed you are running have a lot to do with this. You hear of guys running their gearcases 1" and 2" abouve the pad etc. I guarantee that the gearcase is running with the bottom surface on the water and not in the air with just the piece of skeg dragging.(their angle of attack is just real high) I ran 140mph with the STV and 129mph with the XR2002 and never had to run my gearcase at such extreme heights. What I will tell you is that in both those instances, the motor was close to the boat (very little setback) and the angle of attack of the boat in relation to the water was very flat. If you can envision this the result is the water off the boat doesn't make a huge rise before the gearcase. If you follow my posts on this and other forums, you will note that I always say you will be faster with the MINIMUM setback your combo can get away with. There is no secret to my set up style or the speeds I have run. It is just different from what the 'word' has been. I will bet the farm that no one will ever run 120 or 130 with 14" of setback on their Allison. The farther back you go the more the gearcase will have tough time deciding whether or not it wants to become a ski or a submarine. It will do one or the other. The only answer to the long set back would be run it real high so it only has one choice. Now think this way:: if you have a flat angle of attack with your boat (your bow isn't 2 feet in the air) the water will flow straight back for the most part because you pad isn't displacing the water like a bow high set up. With this better water 'direction' the gearcase can be lower and not have any more drag than the bow high/long setback option. But with the motor close in we have a better balanced boat that will run better as the boat changes attitude over waves etc.

I know this is a long post but I'm really only touching on the subject. I hope this answers the question of what I'm looking for when looking over the transom. (I sometimes drive 60-70mph and jump out of the seat and hang over the back, driverless)(you can do this if your set up has even steering torque) The question was asked and this is the most I've ever told on the subject. I hope some of it makes sense and helps in the quest for more performance.

Randy

 

[BP]

I had always been told the reason for longer set-back was to put the prop in cleaner (less turbulent) water. So if interpet what you are saying correctly..the neutrality(flatter running) of the Allison design minimizes that turbulence right behind the pad.So no need to go back as far with the motor?
thnx for the insite.

 

[John Richied]

I sometimes drive 60-70mph and jump out of the seat and hang over the back, driverless you can do this if your set up has even steering torque

You know I thought I was taking chances with one of my boys driving and me hanging off the back at 70 plus mph… either your flat crazy, or your extreme and crazy! I guess if you want extreme you have to get EXTREME!

Randy, I don’t understand why YOU yourself are not going after “ The Unlimited Bassboat World Speed Record”… but I guess just taking a part in it would make a guy feel pretty good.

 

[John S]

Randy.... what the hell are you doing? Now I gots at least another dozen questions! :lol: You mentioned "angle", so my question now is this- in a perfect world, the propshaft be 1/2 in the water, running perpendicular with the water, with the bullet floating on top, right? Would I at least get a good baseline if I took off with the shaft flat with the pad, or will the boat not "set"? Now I gotta recruit a buddy thats brave enough to hang off the back while I run!!! Thanks to all of you for the replies. Randy... disconnect your phone, cause the next couple of weeks Im gonna have more questions than an alter boy at prayer camp!!!(dont be offended, I went to 12 yrs. of catholic school)

Thanks again-John S :twisted:

 

[GPI Racing]

Hi Bob,

The cleaner water theory is nice if your boat is an old Larson. It does make the round though. Seriously, The long set back is for lever arm. You would need added lever arm if your gearcase is too high. Hence the trend. Truthfully, you need only the set back that gets the job done not more than you need. The trend is excess set back as it cover up a lot of other set up issues. It is harder to set up a boat with the bare minimum set back than the other way around. The result is worth it if you take it to it's final spec though.

Randy

 

[johnnyracer]

Thanks Randy. Almost every one that I looked at that runs pretty good ,you will be able to see the point on the nosecone runnin fairly clean on top of the water. But as I mentioned before its too high with a load in the boat. Drivable but needs more ground speed too lift up and go.

Is this what you have found or am I looking at this the wrong way. ?

I understand that just an ever so small difference in the lip from boat to boat will cause a big difference in where the water coming off the bottom (and also how the cone was installed on the case.)will hit the case .

Johnny

 

[FLYING BUTCHER]

set up

Great thread guys, I'd like to put my two cents in on an experience I had last week. I have never ran my boat very fast with anyone else in it, jsut don't feel comfortable doing it. A friend wanted to go for a ride last Sunday. My boat was full of gas, ALL my fishing stuff, trolling motor etc etc. Like I said first time I ever ran with two. He was directely behind me. The boat never felt so stable, never really got loose at all and ran 98!! Very strange how tight it felt running 14 set back and I could trim it wherever I wanted. Just a stable as heck. Really felt great. This probably doesn't have anything to do with the post but it was the best the boat has felt since I have owned it and it was jammed full. My pennies worth. By the way Randy got the switchboxes thank you very much. Keep an eye out for that used drag boat for me next year!!!

 

[GPI Racing]

Bill's post is a great example. With all the additional weight in the boat, the pad will be running deeper in the water even at 95-100mph. It has too. Therefore the water flow going to prop is traveling more "uphill" and loading the gearcase and prop better, better than when the boat is light.

What does this tell us? If the motor was closer to the boat and slightly lower when he runs it in it's light state, the handling would "feel" much like he just experienced when loaded down. Hate to say it Bill but you need to try it, you'll probably be quicker yet as the boat would take a set faster.

When people ask me questions about their boat I often refer to the boat "talking" to them. Bill's boat is telling him something. If he gves it what it wants he will be rewarded with an even better, quicker ride.

Randy

 

[FLYING BUTCHER]

set up

Damn Randy you have given me a project for the rainy season we are in. Stop by and give me a hand, I'll buy you dinner and a couple beers!!!

 

[Bob Ant]

Great information on your thread Randy.

Now I got a bigger problem. How do I get this big red bouy (was channel marker in Tenn. river )out of the front of my boat or should I leave it there. It seems to help the balance when I am actually fishing off the front fishing deck.

I took you advise literally and was watching the back of the boat while running at 60 to 70. It is amazing how friendly the people in Tenn are as they were all waving at me as I was going by them. I was actually so close that I could hear some of them. I think they were talking about how good of a driver I was.

Now back to my problem. I don't think it is leaking but I may use some cawlking to make sure. Should I put some extra weight in the back. I was thinking about putting all my old burnt pistons and stuff in the live well. That should add about 200 pounds, God knows I never put any fish in it.

Just having some fun, too dark to go out on the water after work so I 'm going crazy. The last couple of posts have been the most informational ones I have read.


Keep it coming. I think almost everyone who owns an Allison on this page can learn something from all your experience.

 

[John Richied]

Before Randy came along on this site, Allisonman (Bryan) was the only one I ever heard say use less setback on your Allison…

I can tell you from personal experience I went from two of us in the XB-2002/225 ProMax running 92-95 mph to running 98.1 mph and 98.9, almost 99 mph!!! All I did was move my setback plate in from 12.5” to 10".

It’s stuck in my (our heads) from past history, what we read, etc. that more set back is better and a higher propshaft height is better. Neither are true with my Allison, but set ups vary.

 

[froggy]

We "old timers" all know about the less setback is better theory. However, to use less setback requires a bunch of setup that many won't want to suffer through. The setup requires careful, iterative, sanding of the pad among other things. One of the quickest Allison drag boats around here runs zero setback (engine bolted directly to the transom).

In the old days Darris recommended 4" of setback on the XTB's and the early 2002's---tells how times change---or do they?

I think an Allison can be made to run well at many different setbacks, depending on how the boat is loaded, etc. I have experienced much better handling at the shorter setbacks as long as the boat would lift.

froggy

 

[jimmyb]

i also think that today's range of props helps the less setback cause (because today's props generally have tons of lift, so you dont need the setback to get the lift)

 

[GFinch]

I'm wondering what would be best for a 1994 XB2003 with a bunch of torque and nothing in or on it. I'm thinking closer than the Allison plate I have, three positions, closest is 11 1/2".
From what I have gathered the early 2003s transom to pad distance is different, therefor needing more set back. I just don't know. I'd like to know, thats why I'm here.

Gary

 

[GotMyAlly]

How applicable is this "less setback is better theory" to fishin boats? Is less setback just for light loads or can an xb2003 loaded to fish still run with less setback?

Mine has always had more steering torque than other boats and I was hoping some l/u work this winter would help with that. But I never thought about too much setback causing setup issues. Maybe it is doing what GPI suggested....can't decide if it wants to run submerged or on top. It would be easy to move my plate in since I have the allison adjustable plate. Just never would have thought I could get enough lift to carry a 2 man fishing load with the plate moved in.

 

[John S]

Just got off the water for my 2nd xb02 experience-just keeps getting more funner! These things really react violently when getting off the gas, I thought that trimming in to slow down was the way to do it (like my xtb21) but I now understand they require a lot more steering/gas/religious input. I am having the time of my life playin with this thing. The 30et has one helluva a lot of lift, but she still dove to the port until I moved the weight to center (30 #). Im gonna raise her 1/4" tomorrow. Randy, do you have a 28et, I would like to have a comparison if I could. It seems like when Im going with the wind, it handles much better - again, opposite of the xtb21 :shock: Also, is it easier to be trimmed positive, then in while accelerating, or am I backwards? It seems like all my experience from my old rig is completely opposite now. Any input welcome.

Thanks-John S

 

[GPI Racing]

John,

Have a 28 but when you get the hang of it and the set up you'll be hard into the limiter. I'm worried you'll do that with the 30.

Randy

 

[John S]

Thanks Randy, its gonna take some time for me to hit the limiter with the 30, Im not confident enough to hold it that long, but it accelerates like a raped ape, so Ill play with it. Im gonna take baby steps on this thing, cause I can tell shes nasty! Hopefully I can get her to run flat before the lakes ice over!

 

[Forkin' Crazy]

Just got off the water for my 2nd xb02 experience-just keeps getting more funner! These things really react violently when getting off the gas, I thought that trimming in to slow down was the way to do it (like my xtb21) but I now understand they require a lot more steering/gas/religious input. I am having the time of my life playin with this thing. Thanks-John S

Ain't that the truth!!! I've got a few hours in mine now. It has to be the funnest boat I have ever owned. After I sell a couple more boats (the cyclone and the checkmate) I am thinking about getting an XR.... :shock: