Tunnel Question . . . Know anything about Transverse Flow?????

[kelvin523]

This thread reads like obfuscated bullsh!t, just saying...

[XstreamVking]

That's from an expert!

[CUDA]

The gimmick is transverse flow, your going WAY too S L O W. ..................

Yeah don't put a plate on your lower unit It will slow you down

[FMP]

This thread reads like obfuscated bullsh!t, just saying...

Please elaborate, and mind the French.

[FMP]

Lots of info and plenty of links http://www.google.com/patents/US5458078

[MN4V]

I've worked on many race tunnel boats since the late 1970's and have tried many different ideas for sponson shapes to help turning and acceleration/speed.
The transverse flow (water spray) doesn't seem to happen, like your sketch, on the race boats. This water spray comes up almost vertical and hits the lift strake
on the vertical tunnel side.
I'm not sure why you've added the pads to your sponsons, but we always like to test one design change at a time. Test the boat as designed/built and then decide
if the boat needs changes to run correctly. There are a lots of things going on in tunnel boat design. Even prop design can make a huge difference.
Mark N

Here is a SST-60 boat I designed and built. I used Jim Russell's TBDP to design the wing section of the tunnel and used a new technique
for the other parts of the boat.
https://youtu.be/_hJf8Sigpt0

[Jimboat]

The transverse flow (water spray) doesn't seem to happen, like your sketch, on the race boats. This water spray comes up almost vertical and hits the lift strake
on the vertical tunnel side. Here is a SST-60 boat I designed and built. I used Jim Russell's TBDP to design the wing section of the tunnel and used a new technique
for the other parts of the boat.

Agree with Mark's comments. There is a "Whisker Spray" that can generate some drag in some circumstances, and effectively designed spray rails can reduce this.

[WillySteve]

My little 10' Cougar Cub tunnel needs a fin to come out good! I installed one from Bob's and it now leaves really nice. Before at the high engine height it blew out really bad!
Actually on N2o it initially clears the water!
This little boat wasn't made to run 60 but it handles extremely well at that speed. IMO it needs to be a few more feet longer though!
The tunnel is 8" deep in the front and 5" in the back with no pads!