Hydro51

I'm trying to find out how much I need to trim off an Accu-Tech Slingshot rudder to run on a PPB drag cat. The current Speedmaster 60/90 tapered rudder that is on it is 4 3/4 inches long overall from where it sits flush at the top of steering block. The leading edge of the 60/90 rudder is 3 5/16 inches long. Should I cut it at 4 3/4 to make it the same overall length or 3 5/16 to make the leading edge the same length?

Thanks, Mark

Ron Olson

My Feedback: (1)

I had a Canadian copy of the Drag Cat and kept the Speedmaster rudder length stock. I just used it as a play boat but did race it once. An old rule of thumb on rudders was to have them at 1-3/4" below the lowest blade of the prop.

Hydro51

That tells me I should cut the slingshot rudder at 4 3/4 to make it the same overall length as the speedmaster 60/90.

Does that old rule of thumb apply to all the different types of hulls/setups?

Ron Olson

My Feedback: (1)

I wouldn't go as far as saying every hull type as there is going to be one that's going to challenge the theory, say a deep-Vee mono as opposed to a shallow-Vee. When a Drag Cat is up to speed, there isn't a whole heckuva lot in the water so a decent length of rudder can't hurt.

Hydro51

Well, the slingshot rudder is 6 inches long compared to the shorter 60/90. I don't want it so long that it might slow it down, but I also don't want it too short to make it not track straight. I guess we can try running it like it is just to see what it does first.

gtdad

I'd start at 5 1/4" overall length....you can't add it back on. See how it tracks and go from there

Hydro51

I got some good setup information from a member on MGB. I cut it at 5 inches per his setup sheet and gave it a nice razors edge. We'll see how it tracks tomorrow.

Thanks guys.

Tahoe1970

Scott , I gave him the link to the set/up sheet I did back around 2010. ��

hendocap

Trick is to buy a couple different blade and cut them at different lengths and see which one gives you what you want. These boats are enough to drive you to drink & drink , & drink some more.

Hydro51

We'll see how it does today with this one cut at 5 inches overall. We might try one at 5 1/4 inches overall and a shorter standoff next time if it's still acting a little finicky, it has a 4 inch standoff on it now. Wally's setup sheet suggests a 2 inch standoff, just trial and error at this point.

gtdad

That setup sheet was before we went to the 4" standoff. Believe me, you want the longer one! Lol! Hendo is right...I drank and drank, until I ran 84 with mine

Ron Olson

My Feedback: (1)

Wally used a thin blade rudder on his Drag Cat as he was picking up water from an under the hull dual pick-up. As much as his boat was on the edge of blowing over it was a wonder that they scooped any water at all!

Hydro51

Water conditions turned out to be too rough to get any decent runs in this past Sunday. I also made some strut adjustments per Wallys setup sheet, have to wait to see what it does.

Ron Olson

My Feedback: (1)

I saw on MGB that Wally gave you a setup sheet but there's also a schematic drawing that I used to have.
Mine wasn't built to run 83 MPH so I wsn't overly fussy on mine. With a dual pick-up rudder I never had a problem with it pulling to the right. I tried to find one of those Hammond boxes locally as supposedly there was a dealer about a mile from me but they didn't carry those anymore so mine just got a radio box from Zippkits.
In the second shot above is Wally, his green boat next to mine at the Flint record trails. I just brought it along that day. The purple one was one of the first out of the mold when Tom Borisch tried having a local guy to him pop one out of the mold. As you might see it didn't work out so hot as it was splitting at the seam, the reason for the 200 MPH tape on it.

Hydro51

The one we have has flush single pickups glassed in the bottom of each of the rear ride pads and it came with a ron buck radio box. I only have 4 pieces of (noodle) flotation in the front of the hull, the rest is a couple bags of air in each sponson used for packing in shipping and wrapped with large bubble wrap. I'll have to take a couple current pictures of it and post them here.

Hydro51

Here it is, as it sits now. The boat is not "mine" per say, but I drive and tend to it as if it were my own at this point for our club president.

Ron Olson

My Feedback: (1)

Nice boat done right.
I found out on mine that I should have moved the engine up a little further to where you can just get to the starter.
I see that you're using one of Dan's pipes, I put one of those on my F-41 Stryker and just ordered the 1" from him today for my 30cc Rampage. Very impressive pipes and I'm not a pipe expert but there was a very noticable difference in speed between that and the pipe that was on it before at the same length setting.
BTW, it won't hurt a bit to run some noodles along the sides either. I've got this paranoia about having a boat going all the way under so I tend to pack the hulls well.

Hydro51

Lol, I worry about sinking one too. I've had this boat blow over on me twice and it stayed a float belly up level with what's in it. If we hit 80mph with this boat, that would be great, but I'm more worried about making it go in a straight line at this point. It also has one of Dan's coils on it mounted to the right stringer in front of the carb.

As for the pipe that's on it, it's his external version and makes all kinds of noise mounted on the GZR 30cc, lol. I recently just put the internal stinger version of that pipe on my hydro set at 13 inches and also noticed an immediate increase in performance from my other pipe set at 13.5 inches.

Ron Olson

My Feedback: (1)

I started mine off at 12-3/4" but the boat only had very limited time on it. Bad health problems late in the running season put a kabosh on getting it out more. His high-voltage system looks good, I might have to give at least one a shot. There's a new prop waiting for open water too, one that G-Force did for me.
What prop are you using? When I saw Wally making his runs he had a fresh H-50 that Chris Hoffmann did up for him.

Tahoe1970

Now that I see these pictures , if the bottom is painted you need to scotch brite the ride pads......knock the shine off the anywhere water touches. I'd do all three ride pads on both sides. I had both of my dragcats painted pretty too , mine ran like **** until I scuffed the ride pads. The clear coat from painting is not slippery in the water and causes a **** load of drag.

Wally

Hydro51

The club president has a 2820/2 for it right now, IDK who it's from or what it's pitched at, it's not my prop. I have a 2816/2 500 I've ran on it and you can here it pulling that prop when it unloads, I haven't gotten any good runs with the 2820 yet.

Hydro51

The entire bottom of the hull was roughed up before we got our hands on the boat, I guess it couldn't hurt to go over it again.