Bottom mods to '77 Southwind tunnel

[comin' unscrewed]

My favorite toy needs a complete makeover. So, while I'm at it I'm gonna make some changes (hopefully improvements http://free.***boat.net/ubb/wink.gif ).
First a short history:
In '96 Gregs shop performed a stage 2 (3?) blueprint on the jet, removed the jet intake, machined it for a shoe & ride plate, and reinstalled it at 4 degrees, and installed a snoot and "R" nozzle with changeable inserts, and a closed loader grate.
After the changes the hull was actually trapping air and working as it was meant to for the first time since it was purchased new by my dad in '77. I gained approximately 7 mph top end (now running a best of 93 mph according to a Rex speedo). But, sometimes on flat water it will loose the air trap on one side or the other and begin to pitch back and forth from side to side. The effect starts gently and increases it's intensity with each side to side shift until I back out of the throttle slightly. (Is this what is referred to as "sponson walking"?).
I spoke to Greg about it on the phone (in '96) and he suggested adding aluminum strips to the inside edge of the outside sponsons to maintain the air trap and help stabilize the boat. (I never did.)
Well the Gel Coat job I did in '95 went south so I've got to redo the boat from top to bottom. And while I'm at it I'm planning to add some depth to the outside sponsons (glass and wood, not aluminum strips).
My questions?
1. How much depth should I add? An inch? More?
2. Do the tunnel gods have any advice or suggestions to improve this particular hull?
Thanks for your help,
Steve

[Skaterfast]

Try to get a look at the Placecraft jet,you know the one that goes over 160mph.Or the Stoker tunnel.I've heard that on the Stoker the tunnels are not the same.One is deeper or wider?

[Jimboat]

Re-modeling your SouthWind tunnel sounds like a fun project. There's lot's of ways to optimize the performance, especially if you're prepared to do some hull mod's. It's important to "tune" the design changes to your hull, so there's no "rules-of-thumb" for what mod's will be best for you.
If you give me some of the hull specifics, I'll run a quick performance and dynamic stability analysis on our "Tunnel Boat Design" software for you.
http://www.aeromarineresearch.com/AeroM_logo1_200.jpg
AeroMarine Research (http://www.aeromarineresearch.com)

[HavasuDreamin']

Be careful not to add too much depth on the outside sponsons. Your pump needs to be able to suck water. Perhaps one thing to consider before modifying your hull is more positive trim: you might not be getting enough air under the hull to carry the nose. Therefore it starts to pack air then the nose drops because there isn't enough air to keep it flying, so you get the side to side pitch. My 19' Daytona does that when I don't give it enough trim (O/B Sorry)! Good luck!