Design Experts, Rough Water Question.
 

I have noticed several different approaches to bottom design (both cats and v's).

One being the longer running length, where the bottom seems to run straight forward and further forward before turning up to the bow (seems most US boats are copied from earlier designs, so most have the same characteristics).

Then, there is what appears to be another idea where the bottom (the straight area) starts sloping up to the bow way far back (seen this more on European style boats.

I believe T2x indicated that they tried this on the Conquests? And too me, the Conqust has the best style of any boat to date (see Jesse James Conquest/Chris Craft).

In other words, if you placed a 32 Conquest on the pavement, and sat a 32 Skater next to it, the Skater will have more contact to the pavement.

I understand that a "knee-jerk" reaction would think that more contact, better rough water ability. But then, as a cat uses a lot of air in the design, I can see the increased drag factor as well.

So, does anyone have any real hands-on experience with these 2 different concepts? Not looking for personal opinions as much as the theories and experience.

Thanks

Not trying to go in another direction with your question but isn't it similar to what a boats waterline length is ?
Everyone here always beats up on boat manufacturers and their susposed overall lenght with or without platforms and other appendages but no one ever discusses waterline length.
ed

Not sure the waterline would be a strong factor in my question as it is the actual keel length before moving up to the bow that I am interested in. Obviously, if the slope up going forward is radical enough, it would affect the waterline some what.

I have always looked at this keel line on boats and wondered the same thing. Hopefully this will turn into a great thread and we all can learn something.

Anyone on this forum a naval architect and into hydrodynamics?

Somehow I believe you have misquoted me and I am not sure from what thread. In fact the more abrupt the bow entry section the better the anti stuff and recover ability in rough water. So you have quoted me backwards. The 35' Jesse James had a fine entry section (more gradual taper, similar to the early Skaters). The Shadows, Chris Cats and later Conquests had a more abrupt bow entry as we eventually went back to the earlier Shadow Cat bow angle with a longer straight bottom section. We found that this was more effective in preventing stuffs at speed and created a "basketball" effect as the bow tended to rebound quicker upon contact with steeper waves.

Photos below show the later, long constant section and more agressive bow angle on the 32' Conquest "Captain America" as compared to the more gradual entry section on the older 32' Rolling Thunder, which tapered upward starting almost immediately forward of the front step.

Peter Hledin followed in pretty much the same vein as his designs incorporated a more abrupt entry after his original "classic" 32. If you look at every Skater designed after the original 40 footer (the next boat he designed after the classic 32) you will note that all of them have a much fuller bow and forward entry.

Hope this clears up any misunderstandings.

T2x

I didn't think i was "quoting" you (T2x)...i was only referencing that somewhere I read that the more gradual taper was used on the Conquests. Sorry for any misunderstanding - I value your information and you have now answer my question, thanks!

I do have another question.

In your opinion, was the Conquest brand a success? The basis for this question is "why" are they not around today? In my opinion, the styling was very aggressive and they looked faster than anything else - even today.

After Mark Lavin was killed in the 35' Jesse James, we simply finished two boats that we had on order. After that I wanted to quit, because I was deeply hurt by the loss. Marce Lavin convinced us to build the 48' JJ as a tribute to his son....in spite of my reluctance at that point. After that I did in fact walk away for good. Since I did all of the selling and management and owned the company it was strictly my decision.

Ken Adams went back to building tunnel boats and various plugs..with one exception, The Linder designed Flying Tiger about 5 years later...After that he worked for Reggie for a number of years. George went on to market safety canopies and act as Technical Chairman for APBA and the early OSS.

I continued with the TV gig until 2001..... when I had a parting of the ways with the APBA. After 20 years.....I think I did enough of that as well.

In recent years I regretted closing Conquest a bit. At the time I was feeling like the accident was a reason to quit, and I walked away from what amounts to the biggest passion in my life.... Boat racing......

Now I think that Mark would have wanted us to continue.

But Cest La Vie.......

T2x

If you watch this video, you'll see in action alot of what's being discussed.

http://media.boatmad.com/gallery/v/m...che_2.wmv.html

The Apache hull is designed with a substantial "forward buoyancy". At the end of the video, you'll see the second boat semi-stuff. It's that significant buoyancy up fron that prevents that, and most likely reduced possibility of serious damage that can occur with a total stuff.

At the same time, looking at the second boat, you'll notice that the actual water contact surface of the boat is quite small when running. Of course, this is a raceboat with substantial power running at top speed. In a pleasure boat/cruising scenario, a boat with less running surface is going to offer less hydrodynamic resistance- equalling less power usage at midrange speeds.

Like everything in boating, there's a compromise to be made.

If you were to, as in the description, set an Apache 41, a Cig Tiger and a Fountain 42 side-by-side on concrete, you'd see much more daylight from the second two.

P.S. The narrator in that vid is the guy right above me.

It REALLY hurts when your friends get killed in something that you built..........................

Amen to that. and it hurts just as badly....22 years later.

Brownie/T2X-
Sorry for the loss of your friend. While I agree with what you are saying- it was his choice to race and NO boat is indestructable to mishaps on the water. You have absolutely NO control over these factors.

You both have contributed ALOT to this sport and we are all thankful for it.

G

It may be just me, but these newest skaters just look like they were designed to stuff.

Ernie

I believe that is more of your eye deceiving you, caused by the cutdown deck sloping downward on top.

I think its deceiving on the trailer. The bow is near level or is level while its running. Also aids in idle visibility. I'm not sure what the others think but seems to me the big bows are not so poplular any more.

Attachment 353845


As far as others talking about the bottoms flat looking longer. I first noticed Reggies 40's doing that. A longer not rockered bottom extends the running surface and gives the boat more reach in the rough.

Many years ago Steve Stepps 22 had the same straight surface as a 35 Cig . Measured like you set them on the floor some thing like 17.5' would touch the floor. Thats why the Cafe's have a springy bow at high speeds. The 22' bottom meanwhile has grown to a 26' and now is called a 28. As a 22 it ran like a big boat and carried a lot of weight well.

On a V's the bow only needs to support the bottom. Notice Reggies latest super V's. Buzzi also designed low long bows.

On the Cats there is more Aero involved.The trend lately was been smaller bows. They get blown around less. They still run the long straight bottom surfaces.

My observations for what they are worth. Pennies? or less?

I would agree with that, the boats are built to be floating/running not strapped to a trailer for maximum performance. it would be the same as tire balancing at speed, not sitting still.

and to add to Jims post above, back in the day, most boats were standing up, lots of fast boats now are sit down, the bow needs to be cut down.

T2x...sad thing about the 35 Jesse James, very sorry for that. On the other hand, this same scenario (i am guessing) has played out in every sport out there.

Did anything good come out of the incident? Like the Canopy systems that have saved "how many" lives since?

And i am sure that the industry has gained much critical information from the "accident" as well and is being used on newer designs - like the facts you have posted from experience, forward recovery comes to mind first.

I know that these things cannot replace the mans life, and everyone who knew him most likely has an "empty" spot in their heart, but "Life Happens" to the best.

I have not read all your posts, but damn, the information you leave on here is "unreplaceable" and extremely valuable in terms of boat education; like spinning props the wrong way. I am sure that has helped an untold amount of boaters.

Anyway, sorry to raise the past and thank you much for your contributions to a great sport that doesn't get enough credit.

AND THAT PICTURE YOU POSTED - THE LINES, ANGLES, AND EVERYTHING, JUST WORK. THAT LOOK NEEDS TO COME BACK!

Wishful Thinking!

Thanks for the kind words, and yes the Lavin Foundation as you so accurately noted has saved a number of lives.

In truth all of us, Brownie, Peter Hledin, Linder, Peters, etc worked off of each other. As one built a hull another would watch and learn from it. The true innovators (and there are very few) took the state of the art and advanced it. Certain boats were examples of this: The first Cougar Cats, the Shadows, The Phillipine Cougar, The Popeye's Super Boat, Rolling Thunder, The Cougar Vee, Jesse James, Copeland's (Sirois') Outboard power head powered hull, Fabio's winged diesel vee, the 40 Skater....... All of these were departures from what came before and while they were evolutionary.... they also were examples of bold and unique change.

This is why I am so intolerant of the heel biting swine who "pop" designs and pawn them off as their own...when in fact they did nothing beyond make a mold and call themselves "original".

While I am grateful for your belief that the Conquest lines should have continued, and I believe that the Captain America design is as good as anything available today, I also believe that , had we continued, our direction would have changed in the years that have passed. My favorite design at present is one that we are about to get some really good data on. It has sat around for 40 years without any advancement or updating at all and it never had the benefit of any kind of engineering budget or financial support.....

I believe it has tremendous untapped potential.

Time will tell.........;);)

T2x

It is an illusion. The forward entry areas on the sponsons of that Skater have tremendous lift and "anti stuff" properties. At speed the forward deck is basically level. Certainly any hull that hits an abrupt wave at speed is susceptable to a stuff, but there have been almost no instances of that happening to Skaters since his earliest designs (the 24 and 32) were replaced with newer, better technology.

If I had to choose any hull today to feel safe in at speed, Peter's boats top the list.

T2x

P.S. Buy a Skater....I did;)

T2x, Does it fly like that? Will it stay up or did it eventually come back down. Or where you feathering the throttle to hold it up?

Pretty cool.

I hear what you are saying... but that shape (top of the boat) is most likely designed to create additional lift by taking advantage of the air moving over the top of the boat (shaped like a wing).

Great post!

I have wondered myself the reason behind the size
of the sponsons going forward.


I realize this is on the bigger end of the scale But take notice on how tall (Deep) the sponsons get towards the nose.

Towards the transom it is approx 3.5 feet high to rubrail.

When measuring the front depth it is almost 5.5 feet high
to rubrail With a quick taper to the bow points.

Its hard getting it all in the camera :eek:But its odvious that it is built huge towards the bow.

I know any excuse to post pictures of my boat!:rolleyes:

Seriously you can really see how big they are.

That is not mine..... That picture was taken back in the 60's. Typically they did not fly like that but if you look at the pix below you will notice a certain consistency in that they were always basically airborne.

T2x

40 foot Switzer? I'm in!

I think that's called a 737..........

Seriously, I am very big on the concept of scale speed....

i.e. a 16 foot tunnel boat at 130mph is equivalent to a 32 cat at 260 mph...or a 48' cat at 390 mph. if all things are equal....(and they never are). While this may not be quite as direct a scale up....it is not far off...and explains why it still takes a lot more talent and stones to drive a Champ boat on a tight course in traffic than to make a one way speed run in a turbine powered cat (with all due respect to the guys who do that as well).

A 40 foot "wing" with proper modern power will do two things:

1. Go very fast.........

2. Attain these amazing speeds with less power than a traditional Cat or even the "Cat Killer" :p.

The issue of course, as it has always been, is the rough water handling and turning capabilities of the design. While Wings were no slouches in the mixed chop they raced in at courses like Lake Havasu, Biscayne Bay/Miami Marine Stadium, etc. They very definitely had a wave height limit and that limit was an absolute. If you scaled the design up to 40 feet or so...that limit would also increase accordingly....but it would still be there..... until and unless certain changes were made in the hydrodynamic design of the sponsons.

That ....my friends is the challenge in a nutshell.... a challenge which I am sure is solvable IMHO.

T2x

Why do you think the European Deep V boats of the early years tended to have a short straight keel area with a shallow long forefoot as opposed to the longer keeled deeper forefoot of the American designs.

Was this trade off of a short footprint strictly to keep the wetted surface down for spee?.And did it work? They stayed with those designs for many years.

And a quick question for Brownie long as we are on the same subject.

I now know that your Nova came from the Donzi 8 metre and I can't remember who you said designed it and if you had any input at the time when the hull was designed for Donzi.I think you had said you were at Donzi at the time

.But anyways here is my question.

Why was that particular design so different from all the other high speed offshore boats of the era with the heavily flared forward topsides and the deep abrupt Forefoot.? Was the hull originally designed for a fishing boat for Donzi and you saw in it a good hull for a rough water offshore boat for the length.I have always admired the Novas and their destinctive looks but i have never rode in one in the rough.How did the hull perform with this different approach to design ?

I love these threads...

T2x I have some questions....

I believe my 40 has a tunnel width of 58 inches. I think the new widebodys are 66 inches. If wider is better, when is a tunnel too wide? Don't you lose alot of compression?

Second question. Some of the early 90's Skaters have a v towards the back of the tunnel. What does that accomplish??

Thanks,
Erik

Erik:

Compression is a function of tunnel angle fore and aft....not width. Increased width gives increased overall lift.

"Too wide" is a condition that will vary from hull to hull and for a specific application. To me, too wide, is when the width compromises the hull strength and makes the boat overly slippery in turns...... The new Skaters have neither problem it seems.

By the way, my 1968 20' Wing Switzer has a wider tunnel than my 28' Skater....and that is probably where the "new" wide tunnel concept came from.

Vee's in tunnels do a couple of things:

1. provide a natural "wedge" aft to reduce loping

2. In our cats the vee went full length in the tunnels to aid in softening the blow from wave impact in the roughest conditions.

T2x

Brownie should answer both of these...but I will provide a picture one of the "early European" vee hulls that Tommy referenced (see Sonny Levi designed English Souter hull T-35below).

Thank you!! :ernaehrung004:

By the way, when you speak of great designers you never seem to mention Randy S. of MTI, why is this.....:party-smiley-004:

Question: which thread did I lift this particular quote from? Seems it has appeared once or twice before here my friend...:drink: Hope you're doing well and planning to shake things up soon. :evilb:

http://www.amalficoastcharter.com/no...barche/?p=1017

Here is a great link I found on Sonny Levis designs.Lot of other stuff in there also --Hickman sea sled etc.Check out the big motor yacht Cat that Levi has on this site.

There is a english translator in the upper right corner.

Basically my original question - but you said it better!

Great designer??? And this may be out of line, but I was under the impression that he was very close to Skater, made some cash in the middle east, came back and started MTI as a direct result of Skater's hard work and years of efforts? Please correct me if I am wrong and I will remove this statement.

To Tommy M. Dick Cole invited me to his design studio to draw the Donzi 7 meter. I knew what I wanted, but was not trained in marine architecture. Dick taught me. My name is on the drawing, and it is the shape that I wanted, but Dick is the brains behind it. As far as the psychology, at the time we were on top of the sport boat (read: useless) world, and I wanted something more utilitarian. The model had mild success. When I started Nova, to build v-drive boats, I stretched the design (again with Dick's help) and made a dandy twin inboard. I always hated aluminum stern drives. Still do................

To T2rex: Speed is a square root function of scale. 16' to 32' is a 2:1 scale. The square root of 2 is 1.41, thus the speed increase is 130mph x 1.41 = 187. The 48' is a scale of 3. Square root is 1.73. 130 x 1.73 = 224mph. Pretty believable stuff when you compare it to the state of th art. 32' Skater, 50' Mystic, all day speeds. Not surprising. I STILL want a 40' Switzer............

Yes and no...... since rarely does the width and depth increase in direct proportion to the length..... so there really never are true scale ups.......

However, I will acknowledge that my scale may have been exagerated under the "poetic license" laws of OSO.:p

One other point using your formula.

If Champ boats race at 130 or so on a 1 mile course, then the precise equivalent would be 32 foot offshore cats racing at 187 on a 1.41 mile course, and 48' cats racing at 224 on a 1.73 mile course.

Like I said, nothing really compares to the cojones of a Champ boat driver.

T2x

I don't mention Randy, simply because he is not, in my opinion, a designer. He is a great set up man, a talented throttleman, and a crafty business man.

Nuff said

T2x

I threw that in because I know it is a very hot subject on both sides of the fence....:drink:

I allways heared and thought that a "longer" running surface will give you more lift. thus., more speed. but more friction. less speed. With the steps and cats.. do we have both ?
What about rough water handing and deadrise? Deeper "V"s better in the rough but slower? Wider "cats' stable but now your driving a Cestna.. It's an age old debate... but I wonder is there will be a design that uses a combination of ALL the evolutions and cats and "V" hulls? A hybrid?
I was involved with the testing of the Black Hawks and step in Lake "X" back in eraly 90's.
I am a "step" advicate even tho my current boat don't have one. (my Dad had a 12'l ittle speed boat in the late 60's with a step)
And the big question.. What can I possibly do to a "V" hull. (Avanti = Coyote Beep Beep hull by Arronow. :) )
To gain speed and "landing" flatter in lieu of often "stern" landing. Great rough water boat but I thnk it's a bit stearn heavy ..


T2.. I respact your inputs and expertise.
Thanks for your comments.