Offshoreonly.com - Pic of stepped hull in action from underneath

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Offshoreonly.com (https://www.offshoreonly.com/forums/)

- General Boating Discussion (https://www.offshoreonly.com/forums/general-boating-discussion-51/)

- - Pic of stepped hull in action from underneath (https://www.offshoreonly.com/forums/general-boating-discussion/293282-pic-stepped-hull-action-underneath.html)

GTOKILLER

03-21-2013 08:45 AM

Quote:

Originally Posted by kevinb230 (Post 3889513)

It helps to break the surface tension of the water to reduce drag. Would be interesting to see a cat and a double step

Or cat W/triple step, I have been searching all over the net I have not found anything yet.......

hogie roll

03-21-2013 08:59 AM

Quote:

Originally Posted by Indy (Post 3889464)

Some thoughts or questions using the pic in post #1 as an example.

The weight of a boat is unchanged. Since part of it is riding on air it makes sense (to me anyway) that those portions not aerated are supporting the weight displaced by the air?

Is there an engineer here that can make some sense of this?

Some of the weight of the boat is being supported by the bubbles.

The helpful part is that the wetted surface area of the hull is much less. This reduces the hydrodynamic drag.

The quality of water of that gives it "surface tension" also causes it to want to stick to things. A boat comes in contact with lots of water then attempts to break free of it as well.

TexasVines

03-21-2013 10:56 AM

I think the next improvement will be a surface coating that mimics shark skin

it looks like one has been invented and is going to be applied to airplanes and I think it is only a mater of time until it winds up in the marine market

http://travel.cnn.com/lufthansa-tests-shark-skin-881186

hogie roll

03-21-2013 12:40 PM

Quote:

Originally Posted by TexasVines (Post 3889878)

Yeah, it seems counterintuitive, but properly designed rough surfaces or ridges can help break the boundary layer of stagnant fluid off of a surface. That's the reason your radio antenna on your car and the hull of a round semisubmersible drilling rig will have a corkscrew rib running around them.

the deep

03-21-2013 01:23 PM

Believe it or not Shark Skin was mentioned a while back by the infamous James Darr . Very interesting .

Cole2534

03-21-2013 01:28 PM

Quote:

Originally Posted by korvetkeith (Post 3889927)

Golf, anyone?

the deep

03-21-2013 01:33 PM

http://www.opdeniep.de/assets/images/Golfball.jpg

PetterM

03-21-2013 02:17 PM

Quote:

Originally Posted by PARADOX (Post 3889472)

There is a bunch of vids. and pix. from Merc Racing on lake X doing the Challanger Offshore 32' and the blackhawks testings.

Where can we find these? :)

PARADOX

03-21-2013 03:20 PM

Quote:

Originally Posted by PetterM (Post 3889976)

Where can we find these? :)

Try to get a hold off Kevin Sceba at Merc Racing or Harry Schull in Pompano Beach, FL. they might have the records. Ken Kawl, VP at the time at Merc. is retired. All my "pre June, 1994 stuff is with my "x'". Test date around late 93-early 94. (don't even remember anymore.) John Simpson (sp?)owner of Challenger Offshore at the time is gone AWOL. I can't even find him. Brownie might have some contact and misc. info. too. I have some old VCR vids the 32' (hull no. 1) with twin 502 Blackhawks running and "parked" at the Pier 33/Thunder marine 1995 Poker Run, (mayden voyage sort of speak) but not underwater.
P

vtown

03-26-2013 01:28 PM

what if you used a large vinyl sticker cutting machine to cut many half inch round holes. Would that be a good way to to beak up the surface and get a few MPH?

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