Ram air stepped hull

[dockdave]

I have a cathedral hull circa early 70's (glass). I've owned 3 of these hulls, these boats used to be rental boats, i believe someone splahed a whaler back in the day. Got another in the barn and i am toying with stepping the hull, and to try what i believe is a new idea. I plan to flush the for-deck just shy of mid ship (xtra large casting pllatform) and plan to fab a console with a very large (whole forward face) intake duct (something similar to lobsta boat racing windshield duct), that will in turn feed forced air into stepped hull. New idea, been done, or idiotic. I would love some feedback from the wizards of boat design.

Dave

[TollyWally]

It's not new, LOL not much is. National Fisherman had a blurb about a similar idea years ago. I might be able to find it.

[dockdave]

TollyWally

Kinda figured not an original concept, but my 22 month old gotta have the coolest "custom" (there is only one) skiff on the skinny water of Moriches.If you could track some 'ol info that would be great. As you can tell this is not a short term project. I appreciate your time.

Dave

_____________________
Stupid is, as stupid does.

[TollyWally]

Hey Dave,
It took a little digging through the archives but I found it. National Fisherman, June 1994. The article is about a guy named Lou Cuccia with an outfit called Controlled Air Systems out of a town called Gretna, LA.

The testbed in the article was a 30' stepped hull catamaran running dual 150 outboards. The step looks to be just aft of halfway. Air is fed through a vertical slot set athwartships above each step and exits through vents in the aft vertical face of the hull where it steps up. The test in the article describes the boat as going at a top speed of 37 knots with the air slot closed. Opening the airway increased the speed to 45 knots. Carrying a 7000# payload the speeds were 33 knots closed and 38 knots open.

The article quoted a guy named Dr. Robert Latorre, chairman of the School of Naval Architecture, University of New Orleans who has written several articles on the subject. At the time of the article they were working out the bugs for monohull applications.

So that is a little bit of info to work on, keep us posted with your ideas and experiments. :)

[dockdave]

TollyWally,

Just want to thank you for your investagative work, excited to see some facts of past executions. In my mind kinda figure the benefits increase as speed increases. I went and flipped the boat last night so i can map a plan to cut the step. I've noticed some boats step forward raking some aft raking, what's the deal? I haven't a clue. some radiused inboard to outboard, some angled straight. Never seen a tri hull stepped. When i do step this puppy are their any benefits to changing the running angle of the aft section?Any hoo thanxs for your time.

Dave