Interesting watch for some...

[Kris Flynn]

I took these videos recently of the water coming off the back of one of my boats... some interesting things I have noticed thats for sure.



And

 

[Terry Keeley]

Why do tunnel hulls (generally) run such high dihedral on the sponsons?

Obviously very stable but awful wet running too?

 

[jaxracer]

Why do tunnel hulls (generally) run such high dihedral on the sponsons?

Obviously very stable but awful wet running too?

I believe that answer relates to cornering ability. Unlike sport 40s and riggers, they run no form of turn fin so the sponson is required to do all of the work to make it an effective round track boat.

You are correct on them tending to run "wet" and is probable cause for drag. If you look at custom built straightaway tunnels, the dihedral on the sponsons is typically virtually eliminated as they opt for a flatter running surface. From my experience, flatter is faster, but higher sponson dihedral tend to corner much quicker and better at higher speeds.

-Mitch Jr.

 

[Wasted wages]

definitely plows a distinct groove in the water following the sponson on the straightaway !!