As I stated above there is a caveat when designing stepped hulls that the L/B ratio plays a very large roll in determining the number of steps. As you no doubt know the higher the aspect ratio of the surface the more efficient it is. For example your 33ft model would not benefit from having two steps since the lifting surfaces would become much lower aspect ratio.

So on a longer narrow boat having multiple steps does improve efficiency since the L/B ratio is rather large thus making for a small aspect ratio and an in efficient single step boat.

This does not make more steps beyond 2 ate better though as it can make the boat very resistant to pitch in a seaway which could make the boat neigh on impossible to drive effectively.

Your quote does bring up a very important issue in step design, and that is the angle of attack of the step and the length of the step. Two more extremely important variables in making an efficient stepped hull boat. Too low an angle of attack combined with too long of a step and you end up with a step that has more wetted surface than it needs and may cause the same problem as mentioned above. Savitsky presented a paper in 2009 that was based on a series of model tests to predict the wave height aft of a step to give designers an easy tool to help predict wake height and using his equations from his hydrodynamic design of planing hulls to calculate the lift the after-bodies are capable of producing.

I've posted a link to a dropbox with that paper in it.

https://www.dropbox.com/s/c0ijod7en3...%20%282%29.pdf

I don't think either of us is in disagreement with the other about the last sentence of Potgieter's essay.

As far as case studies research and such...Papers from Chesapeake powerboat symposium,FAST conference papers, HSBO papers, SNAME papers, RINA papers, Dr. Doctors UofM class notes "hydrodynamics of high-speed small craft", Faltinsen's book Hydrodynamics of high-speed marine vehicles, and class notes from my high speed hydrodynamics course.

This thread is effing hilarious. It's amazing how easily things fly right over the tops of the heads of supposedly educated and intelligent individuals. Thanks to all the rocket surgeons who failed to recognize the sarcasm / humor intended by the OP.

Good one.
Personaly, I have no need for them, give me a perfect straight bottm anytime. They just arn't worth all the trouble that comes with them. But I am also a old "F":whistle:

You left out the word "really" .....:evilb:

sorry, to old to remember,

you ever watch a sv race in opa?? the spins can make you dizzy and say wahoo.....

You would be interested to know after 13 years of building this boat and also mentioning we use an insert in a V-bottom mold, we have seen every effect you can have on the aft running surface.

We do things completely different if we are going over the "90" or "100" mark. Pretty much a zero angle of attack and these adjustments are what make it handle. Also we have changed the trailing edge of the forward running surface miniscule amounts and seen major changes it attitude.

Unfortunately you just can't spend that many years on theories and math with a known end result in the class room. Or for that matter in a test tank.

My point to the original post is if there is a known issue why isn't it fixed instead of a sticker warning you to "hang on, you're about to go swimming".

One thing to think about as my theory: The more times the water reattaches it self to the bottom of the boat (each step) the more resistance and confusion it creates. In a turn we only have the re-attachment at the transom. With a multi-step boat we have multiple re-attachements.

Curious as to your opinion on this.

Did you actually mean 2000-2004?

[QUOTE=ActiveThunder;3919876]You would be interested to know after 13 years of building this boat and also mentioning we use an insert in a V-bottom mold,


Now that is what I like you can still build me a non-step after I hit the power ball:cartman:

[QUOTE=cosmic12;3920211]Or I could build you a boat correctly engineered to be faster, more efficient and MUCH MORE user friendly since you don't need this:

Maybe someday, I do know if that day ever comes it will be your door I will be knocking on.

I have a question ActiveThunder. Say I want a 33AT with 700/NXTs. If I ordered one new, would it have the exact same bottom as AJ's 33AT or would it be "tweaked" for the bigger power?

Good question.

I would reduce the height of the step and slide it back just a hair.

Umm...this thread popped into my mind when I saw THIS one in General Discussion: http://www.offshoreonly.com/forums/g...-one-hurt.html

Wonder if there was a sticker on the boat?

Funny how this thread resurfaced about an hour before that one.....

Its like you are prescient or something...

Wow
 

Nice move taking someones misfortune to take a stab at another manufacturer.

this thread started after the cig splash in Havasoooooo

05-19-2013, 11:57 AM#1




TeamSaris





Driver-441 Racer
--------------------------------------------------------------------------------
My Boats: : 32 Cobra Raceboat, 27 Avanti Raceboat 27 Kryptonite RaceboatJoin Date: Aug 2004Location: Lake GeorgePosts: 10,201Feedback Score: 0




Holy Hell!



We hosted our little demo race event this weekend, about 2-3 mile circle track. RedMatter brought his 39 TG with the 1100/M8 package. Let me tell you, ive run a LOT of big power vees and none of them compared to this boat. The handling over 100 was flawless, putting her into turns at 90 wasnt an issue, the boat does everything right. And when you lay into it, you better be ready...the acceleration is MIND BLOWING. Video and pictures to come.
HUGE thanks to Ken (RedMatter) for being crazy enough to throw me the wheel and throttles for a few laps


Here are some pictures of the boat in last years event
Sharkey-Images | Demo Race Three





Saris Racing Team Ocean City 2012...AIR - YouTube <<<NEW VID. Follow @SarisRacingTeam




THIS GUY DIDNT SEEM TO HAVE ANY TROUBLE WITH TURNING A T/S TOP GUN AT 90+ MPH........
BTW, I had a Formula 382 with the same sticker in it. I dont think they are openly admitting the hull design sucks, but rather warning operators what CAN HAPPEN with a stepped hull boat. I am an AT fan for sure, but when the owner of a boat company slams another on a public forum, its kind of a turn off for me....... A few yrs ago I was considering buying at certain staggered 37 AT here in CT. In talking to the owner, he himself had taken a sharp corner and spun and rolled the boat ejecting a few people and the boat went under. Now, I know that was the ONLY staggered 37 AT ever made......is that because you actually took your own advice and fixed a bad hull design so this wouldnt happen again? Or is it still the same design minus the stagger? IMO, it was a good hull design, with an inexperienced driver......just like most other spin outs.

Just to clarify I love love love the At`s not the small one I owned (too small for lake Michigan) but the 37 are beautiful and come with all the ameneties/ storage I`d love to have..... BUT I`m with Kreed.

I didn't watch the whole video; is there footage of a Cigarette in there?

i believe we are crossing over conversations; with a video of a race posted in a topic that was about pleasure boats.

I would personally run a race prepped boat differently than a pleasure boat.
When they put the first seat belts in cars, it didn't make them safer. It made the drivers go faster and take more risks because the felt safer. The same goes for all the preparations put into a race boat.

Cigarette makes fine machines. However, their lawyers more than likely "made" that sticker.

"Now, I know that was the ONLY staggered 37 AT ever made......is that because you actually took your own advice and fixed a bad hull design so this wouldn't happen again? Or is it still the same design minus the stagger? IMO, it was a good hull design, with an inexperienced driver......just like most other spin outs."

I don't think the stagger was the issue but it could have contributed to it. If it wasn't staggered could they have recovered the turn? I really don't know. However based on witnesses, alcohol and a bad choice seems to be the major contributing factors, I will say I have spent quite a bit of time working with the bottoms of my boats to make them as safe as possible but also with the best efficiency increases. I feel right now step placement in both the 33 and 37 is right where it needs to be, Next up will be the 29 later this year.

A little know fact: Every boat is flipped upside down (on purpose) and blue-printed before it ever hits the water. That is how dedicated we are to make sure things are right.

As far as a decal on the dash, if there ever is an issue based on poor hull design or placement of the CG, the sticker isn't going to do squat in court if there are severe injuries or worse.

Hope this enlightens you a little on my thoughts and how we build the boat.

Based on the history of certain boats, correcting what might be a known issue seems in order. However if you have a dedicated mold without any chance to make adjustments to I can see why you would stay status quo. I would dare say that reducing ALL weight in the front of the boat would certainly help with the boat swapping ends. That is reason enough for a no-stagger 37.

Pat maybe you comment on the 37 Active Thunder (staggard boat) that spun out in Branford CT a few years back. As I remember the witnesses on the beach said the boat came in the river at speed and made a turn as it was starting to slow and it hooked and spun throwing all the passangers in to the water. Correct me where I am wrong and give us all some insight was this boat a" best guess" design. There must have been a reason that AT has not kept producing the staggard design.

The 37 stagger AT had 1/2 a dozen owners or so, over 10 years or so. It spun one time, ~10 years after it was built; (while full of booze) and boom, it's now a turd?

Someone is reaching. You can spin a newer model AT out. I can tell you how to do it; but you are going to have to work REALLY hard to make it happen--setting the boat up completely atypical to any normal running condition requirements. I had to turn my personal 37' so hard while navigating the "S-turns" on Smith Mountain Lake several years ago, that I put the rub rail in the water and my auto bilge came on when I straightened out (I had a PWC cut directly in front of me while I was running around 50mph).

But, nah; they can't turn.

The guy who designed and patented the bottom of the AT; did so with step, transom, and outdrive placement in mind--for handling and efficiency. I invite ANYONE to come down to Pompano; and Pat or I will walk you a few doors over to his "laboratory" and introduce you to him so you can bounce your advanced turning theories off of him directly. :D

PS; make sure you bring note taking materials, and plan to stay for happy hour. :drink:

I have to say I mirror what Kreed stated about being an AT fan. Nice looking boats Pat and you seem to have a nice loyal following. I have always said AT would be on a short list if I was to build a new boat. I feel AT fills a void that Cigarette and other manufactures have left out. For me that market is a 90mph boat with a full cabin stock power and Bravos, this keeps the price down. I have to say to me it is a turn off watching another manufacture try to exploit an accident for gain. How many T/S Cigs have been built and spun out vs. AT? Those in glass house should not throw stones. Unless Pat with all the experience you have can tell us what exactly is the design flaw with one of the best selling boats??

We keep the $hitter full on the AT to help with that. :drink:

I'm not exploiting another manufacturer. Simply asked a stupid question. I kept this in the AT forum as 'a little poking fun' thread. It actually became informative and interesting when the kid that recently graduated with a degree came on board for a few days.

As far as glass houses, we have had 3 rollovers. 2 were with factory people at the helm. I don't hide from the truth, I know exactly what happened in 2 of the 3 events first hand. The stagger boat I only know what I saw here on OSO and second hand from one person who claims he saw it. Now how many of the other boats?

If I know of any issues I correct them immediately. And beyond problems am always trying to improve the boats from something as simple as hardware to whatever I hear the people want to see in a boat.

[QUOTE=Sydwayz;3933141]The 37 stagger AT had 1/2 a dozen owners or so, over 10 years or so. It spun one time, ~10 years after it was built; (while full of booze) and boom, it's now a turd?

Someone is reaching. You can spin a newer model AT out



I never said it was a turd....only one on here that mentions it and that is you! ........I was actually interested in buying the boat. I liked it then, and Id still buy it now. And I belive your right, lawyers put that sticker in alot of boats....including Cigs. I was just surprised that a company owner would start a "just poking fun" thread knowing that behind every joke is a certain amount of belief in the joke! So maybe, Pat has something against Cigarette, who knows....but if he really was "poking fun" because of a spin out, then I hate to see his "Outerlimits fun thread"! LOL.....This post is it for me guys, its been fun. Hope to meet you some day for a coctail in FLA.

I guess you missed this PowerBoat Magazine ad.

22' and 42'? I've never seen either of those.

22:
http://www.offshoreonly.com/forums/a...r-banshee.html

Some old footage including the 22AT here:
http://www.youtube.com/watch?v=a736aQE6n7g 42/43 put on hold until recreational lending comes back.

awesome video ! really like that boat best revenge. 32 ?

Yep, it's a 32. It's owned by a guy named Harsin here on the board; out of Indiana.

It was originally built and owned by a guy named ActiveThunderTodd here on OSO. Good guy. The "Best Revenge" part was in response to his divorce.

i gotta get a 32 . figured it was something like that . my wife hates boats and everything about them so i get it . maybe its just because im obsessed .

Thats a cool old video i have a copy of it and my boat is on the cover.

That's awesome. You should post more old promotional material.

I think Active Thunder should get into the ski / wake boat bizz.....hell 23 ft boats with 120K MSRP...why not...

someone shot this video again in hd! 2013 version

Best Revenge is the nicest looking 32.

Please tell me the 42/43 is staggered, if its not good luck trying to sell those cig and Outerlimits owners on it. I comprehend what pay says about gaining nothing from a staggered setup, but good luck telling 95 percent of those guys....