Available: Consultant Specialist in High Speed & Unconventional Projects

[chris.mckesson]

I am a project consultant with 25+ years specialized experience in unconventional and high speed vessels. Projects include Naval and Commercial Surface Effect Ships, SWATHs, Catamarans, and Monohulls.

I am retiring from full-time employment to pursue contract and telecommute opportunities.

Full details can be found at: http://www.mckesson.us/chris/consulting/

Chris B. McKesson, PE

[BMcF]

You lucky dog you...I'll see you Monday at the HSSL review and you can tell me all about it.

[chris.mckesson]

...I was hoping you would be my one of my clients, Bill.

See you Monday.

Chris McKesson

[BMcF]

..well there *might* be a couple real SES projects coming out at long last..one is even a passenger ferry ...

[Leo Lazauskas]

Originally Posted by chris.mckesson

I am a project consultant with 25+ years specialized experience in unconventional and high speed vessels. Projects include Naval and Commercial Surface Effect Ships, SWATHs, Catamarans, and Monohulls.

I am retiring from full-time employment to pursue contract and telecommute opportunities.

Full details can be found at: http://www.mckesson.us/chris/consulting/

Chris B. McKesson, PE

All the best with the sea-change, Chris!

Leo.

[chris.mckesson]

Hello Leo - thank you for those kind wishes.

I am indeed looking forward to a new set of challenges.

Bill McFann and I have just come from an interesting meeting at ONR with lots of presentations on CFD and automatic hull optimization. This brought to my mind many memories of GODZILLA, which I just wish I could get more people interested in. Your product is one of the most exciting pieces of hydro work I have seen in many years.

Are you in contact with Larry Doctors? Perhaps we will see you at the Marine Hydrodynamics symposium in Sydney in August 2008?

All the best,

Chris McKesson

[Leo Lazauskas]

Originally Posted by chris.mckesson

Hello Leo - thank you for those kind wishes.

I am indeed looking forward to a new set of challenges.

Bill McFann and I have just come from an interesting meeting at ONR with lots of presentations on CFD and automatic hull optimization. This brought to my mind many memories of GODZILLA, which I just wish I could get more people interested in. Your product is one of the most exciting pieces of hydro work I have seen in many years.

Are you in contact with Larry Doctors? Perhaps we will see you at the Marine Hydrodynamics symposium in Sydney in August 2008?

All the best,

Chris McKesson

Although I only have sporadic contact with Lawry (as he is
affectionately known here) he has been a great influence.
We've been citing each others papers for over 10 years now.
He and Ernie Tuck are, as you know, great admirers of
another Australian, J. H. Michell.

Nice work on the resistance components of SES, by the way.
I still have great reservations about the "finite hollow"
approach to transom sterns flows, even though I use it myself
on occasions. I read some recent work by Lawry and Bob Beck
on the problem and I'm still not convinced. I always feel
uncomfortable when form factors of more than about 1.05 are
used to bring theory in line with experiments. Values of 1.25
or more are a real admission that our theories are inadequate.

Many years ago Lawry made an offhand remark to me that giving
Michlet and Godzilla away for free was like letting babies play
with razors. They are not easy programs for beginners and I
have been sent umpteen input files to decipher which had
the ship upside-down or back to front, or with speed in knots
and length in metres etc. I think that they are useful programs,
but they need to be used cautiously within their domain of
applicability, and the results sometimes need careful
interpretation.

Here's something I'm still trying to automate within Godzilla
that might amuse you...

Suppose that Godzilla has actually found a ship that is in some
sense optimal. What is the second-best ship that is not too
similar to the optimal vessel? (For example, it's of no great use
knowing that the second best ship is a micron shorter than the
optimal one). I think that it would be very useful to have in
hand two or more (disimilar) designs with, for example, very
similar total resistance over a range of speeds. It would
certainly give naval architects a wide field in which to exercise
their voodoo.

There's probably a way of finding these optimal and sub-optimal
ships using multiple objectives and/or a variety of "secondary"
constraints. The challenge is to find a small set of constraints
that does the job.

Any presentations remotely along those lines at the ONR meeting?

Regards,
Leo.

[chris.mckesson]

Intriguing! you mean a case where, say, the best hull is 400 feet and the second best hull turns out to be 200 feet. And then you start looking for octave-periodicity or something. Very intriguing idea, i will have to think on it. I saw an interesting graphical method of presenting optima, in a paper from belgrade. The problem was one of presenting ships on a 2D design space - say Length & Beam. But of course the problem is many-more-than-2 dimensional. In this presentation each design was analysed to determine it's 'goodness', and then when any plot was made on a 2D plan, the size of the spot indicated the total goodness in all the other dimensions. The result looked like a star field, with the first magnitude stars shown as larger than their dimmer cousins. By plotting a pareto frontier in this way, in some of the cases one found two "galactic centers" one at X1-Y1, and the other at some other XY. And you could tell quickly visually because of this trick with the size of the plotting-points.

Well anyway - I'm sorry for that fractured explanation. But suffice it to say that I am intrigued by the idea of "neighboring plateaus" and will give it some more thought.

And by the way: The first time I ran GODZILLA it was on a SLICE, and indeed I put the ship in sideways (I got X and Y switched.) It was great entertainment to watch the evolutionary process correct my error, as the hulls got fatter in one direction and skinnier in the other, until it had morphed the hulls into the direction of flow. In the case of a SLICE, with four hulls arranged in a square, the effect was a visually dramatic correction of my own mistake!

All the best,

Chris

[BMcF]

Don't want to butt in on this..but about 8 years ago I was contracted to provide inputs (for SES platforms) to a group that was under contract to develop the kind of tool that Leo was asking about. The goal was to be able to input a set of top-level requirements for performance parameters like speed, paylod, and range, any constraints on size, draft..whatever..and let it run. The output was a ranked set of 'point designs' that could be, of course, any of the various vessel types, including hybrids, that were 'in' the mix of options that the 'tool' supported. If I recall correctly there were at least 8 or 10 distinctly different 'families' of vessel types in the program and a fairly wide range of propulsion system options as well.

Not sure whatever came out of that in the end..or where it went. Chris might know; MAPC was the prime contractor on that effort. Ring any bells, Chris?

[Leo Lazauskas]

Originally Posted by BMcF

Don't want to butt in on this..but about 8 years ago I was contracted to provide inputs (for SES platforms) to a group that was under contract to develop the kind of tool that Leo was asking about. The goal was to be able to input a set of top-level requirements for performance parameters like speed, paylod, and range, any constraints on size, draft..whatever..and let it run. The output was a ranked set of 'point designs' that could be, of course, any of the various vessel types, including hybrids, that were 'in' the mix of options that the 'tool' supported. If I recall correctly there were at least 8 or 10 distinctly different 'families' of vessel types in the program and a fairly wide range of propulsion system options as well.

Not sure whatever came out of that in the end..or where it went. Chris might know; MAPC was the prime contractor on that effort. Ring any bells, Chris?

Butt away, Bill. There was a qualitative spreadsheet tool like that described in "High-Speed Sealift Technology" Vol. 1 by Owen K. Ritter and Michael T. Templeton, CDNSWC-TSSD-98-009, Sept. 1998.

Leo.

[BMcF]

That fits the description in all respects, Leo..except for the date. Perhaps the effort I was involved with was an 'extension' or improvement of that tool..it was indeed spreadsheet-based.

I had to chuckle about how it worked..if you included rather large numbers for speed and range in your point-design requirements and rational/moderate payload fractions, the SES always 'won'.

[chris.mckesson]

So, along those lines: I am intrigued at the concept of continuous design spaces across craft types.

The initial example is of course the -maran, where for values of x=0 you get a monohull, x=1 gives a catamaran, and 0<x<1 gives all possible trimarans.

(Leo, that was yours, wasn't it?)

I did a design tool exercise similar to Bill's, for the Special Warfare community. In that one I defined a space of between catamarans and WIGs, with Tunnel Hulls occupying all the middle ground.

We did NOT include powered lift in the same continuum - we gave SES their own 'sheet' of the workbook - but it's clear that they do in fact belong in that continuum. Look at a PAR-WIG like the Caspian Sea Monster (http://membres.lycos.fr/dracken/Ekra...rono_russe.jpg) - surely this is some sort of degenerate case of an SES.

So now we have a three-axis design space:

Leo's hull indicator (called "x" above)
A Cat-Tunnel-WIG parameter (call it "y")
A Powered Lift -to- Passive Lift parameter. (call it "z")

Of course, I'm not sure why this intrigues me so much!

I do have a paper from HIPER 99 at which we postulated that the optimum craft will always lie on an edge of the design space...maybe even always at a corner. This is because "hybrids are always bad" - which is of course patently untrue in a thousand real-world cases, and yet seems true in high performance craft.

OK - phone just rang - gotta go!

Chris McKesson

[Leo Lazauskas]

Originally Posted by BMcF

That fits the description in all respects, Leo..except for the date. Perhaps the effort I was involved with was an 'extension' or improvement of that tool..it was indeed spreadsheet-based.

I had to chuckle about how it worked..if you included rather large numbers for speed and range in your point-design requirements and rational/moderate payload fractions, the SES always 'won'.

The spreadsheet I was referring to wasn't available to attendees at the time of the workshop and I think that it took a while to be released. I couldn't work who actually wrote about it at the CCDoTT workshop, although I suspect that Band, Lavis et al were involved, as well as C. Kennell.

Good luck!
Leo.

[BMcF]

Originally Posted by Leo Lazauskas

I couldn't work who actually wrote about it at the CCDoTT workshop, although I suspect that Band, Lavis et al were involved, as well as C. Kennell.

Good luck!
Leo.

LOL..it always comes down the same small group of 'suspects' in most cases anyway. Colin was also at the recent ONR meeting with Chris and I..

[Leo Lazauskas]

Originally Posted by chris.mckesson

So, along those lines: I am intrigued at the concept of continuous design spaces across craft types.

The initial example is of course the -maran, where for values of x=0 you get a monohull, x=1 gives a catamaran, and 0<x<1 gives all possible trimarans.

(Leo, that was yours, wasn't it?)

I did a design tool exercise similar to Bill's, for the Special Warfare community. In that one I defined a space of between catamarans and WIGs, with Tunnel Hulls occupying all the middle ground.

We did NOT include powered lift in the same continuum - we gave SES their own 'sheet' of the workbook - but it's clear that they do in fact belong in that continuum. Look at a PAR-WIG like the Caspian Sea Monster (http://membres.lycos.fr/dracken/Ekra...rono_russe.jpg) - surely this is some sort of degenerate case of an SES.

So now we have a three-axis design space:

Leo's hull indicator (called "x" above)
A Cat-Tunnel-WIG parameter (call it "y")
A Powered Lift -to- Passive Lift parameter. (call it "z")

Of course, I'm not sure why this intrigues me so much!

I do have a paper from HIPER 99 at which we postulated that the optimum craft will always lie on an edge of the design space...maybe even always at a corner. This is because "hybrids are always bad" - which is of course patently untrue in a thousand real-world cases, and yet seems true in high performance craft.

OK - phone just rang - gotta go!

Chris McKesson

Yes, the "generalised trimaran" factor was mine. I used it in a paper with Ernie Tuck at FAST'97. I recently tried to combine it with another parameter so that I could have generalised SES with two or three sidehulls, (or none for "pure" hovercraft) but I haven't finished that work. I hadn't thought of it in terms of WIG, though. That sounds like your sustention cube.

As to why such things might be intriguing? Maybe now that you're a telecommuting consultant you have plenty of time for pondering. It's the sort of thing that has kept me poor (but happy) for the last 12 or so years.

Cheers,
Leo.