SOUTHWIND TUNNEL Pilots - I need help

[bigriverdog]

I am the head wrench on my sons Southwind Tunnel Dragster and it has some major handling issues. It is very spooky to drive at lower speeds and I am not sure what to expect from this hull. If any of you could help with some advanced setup for this hull, I would really appreciate some phone time or e-mail discussion. Feel free to PM me.

[Nucking futs]

Come on over to www.southwindjetboats.com and we can help.

[comin' unscrewed]

I am the head wrench on my sons Southwind Tunnel Dragster and it has some major handling issues. It is very spooky to drive at lower speeds and I am not sure what to expect from this hull. If any of you could help with some advanced setup for this hull, I would really appreciate some phone time or e-mail discussion. Feel free to PM me.
Can you give some details? "Spooky to drive at lower speeds" isn't much to go on.

[dtr352]

The one time I drove mine before the motor went to hell I noticed that if I left the place diverter all the way down to long the boat would experience a lot of bow dteer. This was the first time I had driven this particular boat or any jet for that matter so I was just playing with the trim. Not knowing exactly what your boat was doing this is all I can say. Good luck.

[bigriverdog]

The boat wants to hunt at slower speeds (go everywhere but straight). It's like it is running the strakes. The pump and bushings are new and tight and the steering is also good. It doesn't seem to react much to nozzle angle at these speeds. It doesn't have a droop and I am wondering if the higher nozzle is pushing the front end down. The boat has very little bow lift gatting to plane.

[FOURQ]

sounds like it stering with the bow to me. you might need to change the setup.
4Q

[BrendellaJet]

sounds like it stering with the bow to me. you might need to change the setup.
4Q
I think hes on to that...what in particular?

[Nucking futs]

May be in the entrapment plates,may be to low.What are they set at?If you have no droop put the plates up at 2* for a starting point.Do you have a rideplate and where is that set at?What speeds are you talking about?Just after you plane out or at a cruiseing speed?Do you have ane porpose in it?

[FOURQ]

right now my plates are set at 2* up and the ride plate at 3* up and it launches out of the hole so good it almost comes compleetly out of the water, when i first took it out after i got it it was at 2* on the ride plate and some doof set the plates at an angle going down twards the center and it did the same thing. I took the diverter off and added a american turbine ft droop and set the plates at 2* all the way around and it was gone and worked real good. so i would start with the plates at 2* all the way around and see what you get.just rember ALL boats are diffrent even out of the same mold so be carefull when you first hit it as it may want to bite ya..
4Q

[bigriverdog]

4Q and Nucking futs I think you have it. Its feels like it is running the nose. I also spoke with Money Sucker and his set up is just as you recommended. I haven't really messed with the cav plates and they are about 0 and I am at 4 degrees on the ride plate. I really think a droop is needed just to get the nozzle closer to the water to get some more lift. Thanks so much for the help. I am going to set it where you guys recommend, as a base line and go from there.

[Nucking futs]

The cav plates are used as air entrapment plates.They should not be running in the water at all if the set up is correct.That is what helps the boat gain lift.It acts like a big venturie and air passes through the the tunnels and then the plates let the air escape almost like suspending it in air and if you dont have enough plate you basicly are putting the boat on its bow or the same can happen if you put to much plate in it, it will want to fly the nose. There is a fine line and you must adjust a little at a time and try to find the sweet spot.I hope this makes sence and if not i will try to explain differently.......Tim

[Cs19]

I kinda agree. I do think the plates affect the boat at cruising speeds alot.
We run ours (cav plates) even with the outside sponson, its basiclly an extension. Just take a piece of metal or some sort of straight edge and check to see where they (cav plates) are in relation to the sponson in front of it. Unless you have an electronic angle finder which most people do not have.
How are you guys checking your settings?
I find it hard to believe that the slower SWTD's are actually running with the tunnells tottally dry at top speed,we are talking about a what, 3 inch tunnell?
Now on a boat like BP's its a different story.

[Nucking futs]

I agree with you on the slower tunnels ,just was stating how it worked and what the plates were to do at best.Alot of the river runners wont get enough lift for the plates to be out of the water and was trying to give an easy explination on how and why they were there..........Tim

[bigriverdog]

CS19, There is about 3 inches from the top of the tunnel to the outside sponse but the center pod hangs down about 6" +. The outter sponses almost act like outriggers.
I haven't given the cav plates much attention because I thought once on plane they were a so what. Obviously I was wrong and will need to see if they may be contributing to the problem.
Thanks to all for the input. Its great to have a forum that gets so much great response. See ya on the water. :p

[Cs19]

Ya, the only way your gonna get anywhere is by trying stuff, let us know what you find out.
I re-read my post and it didnt make sence, what I was trying to say was we run ours just as an extension of the tops of the tunnells, not the sponsons,and no up or down in the plate at all.
Good luck with it Riverdog.

[FOURQ]

what I was trying to say was we run ours just as an extension of the tops of the tunnells, not the sponsons,and no up or down in the plate at all..
that could ba a little dangerous beeing that it could give you a bit to much vertical lift...hows that thing ride???real free?
4Q

[LVjetboy]

Hmm...lots of ideas flying around. I'm running my tunnel plates zero and ride plate about 2 degrees. Not spooky at low speed or high...although not a true SW either. As for tunnel plate affect vs speed? Anyone here actually measured when their tunnel plate lifts out of the water? I doubt it.
jer

[Nucking futs]

No there is no way to actually measure it but we have lots of pics to show that they are in deed out of the water.And yes it had bottom mods done and was not a out of mold bottom.It was prety close to what MR.P had posted on his boat.