Blind faith: engineers cannot afford it

Miscellaneous Musings from the Technical Director

Let me share a story from my first technical internship when I was in high school back in the 1970s. I was working in the engineering department of a pump company. Our analytical tools were simple calculators – and a new “computer”, with keyboard, screen, and printer.

Only one of the engineers took the time to learn how to use the new computer, so he was the only one that regularly used it for calculations. (Really, it was little more than an automated calculator.) The engineering boss distrusted the computer. There were no background hand calculations to cross-check, and he often asked for a hand check of the results. “Math is math” and the computer answers were all OK, but I always suspected that he secretly wanted it to fail so he could justify having it removed from the department.

Well, as it happened, one day the boss was asked to supply a calculation for a meeting that was to begin in an hour. The only way he was able get any numbers for the meeting was from the engineer using the computer. Our boss took the computer’s very simple printout into the meeting, and his bosses apparently were very impressed with his department’s use of modern technology. Immediately, the engineering boss was a “convert”.

From that moment, every submittal was greeted with the phrase, “Did you run it through the computer?” Even the simplest arithmetic was cross-checked with the computer. He no longer used hand calculations to check the computer, he took the computer’s results on “blind faith” and used it to check everything else. Even as a very green “newby” I knew that this was a waste of time, but the boss persisted.

Our computer “guru” then had an inspiration. He wrote a little program to take any number that you entered, format it with some nice text, and spit it out as an answer that was “put through the computer”. This was a brilliant solution to a sticky problem – until the boss found out. Of course, he was furious, but he also acknowledged the silliness of his demands.

His “blind faith” in a new technology clouded his engineering instincts, until he had his own “emperor-has-no-clothes” moment. The new technology was fabulous, but it was not a universal solution for all problems. Throughout my personal employment experience, and in my position leading a technical team, I have never forgotten this episode from my earliest days in engineering. It has helped guide the design of our commercial software products, and the acquisition of our own engineering tools.

This also might be a lesson for today’s young engineers. Seek out and appreciate cutting edge technology, but be careful and avoid the temptation of placing “blind faith” in any tool or advertised capability. Take the time to look past the superficial and really see what the technology can do, cannot do, and where it can most effectively be applied.

Onboard speed-power management – a "feel good" solution?

Miscellaneous Musings from the Technical Director

Here’s my contention:

onboard speed-power management (SPM) systems are nothing more than a “feel-good” solution for a problem that doesn’t exist.

OK, now that I have that out of the way, let me fill in some details…

A problem that doesn’t exist?

What is a problem? Dictionaries define it as “a question proposed for solution or discussion” (www.dictionary.com). I submit that what may be a “problem” to one is not necessarily a “problem” to another. Likewise a “solution” to one is not necessarily a “solution” to another. I believe that any solution to a problem requires commitment by those responsible to implement the solution. A tool that is unused or misused is nothing more than a “feel good” solution.

Technically, there is real opportunity for fuel reduction using SPM systems. We even wrote a technical paper about this some 10 years ago [MacPherson 1999], and we were a core partner in the development of a such a system for the U.S. Coast Guard R&D Center [Macesker 1999]. So, I do not mean that there is not a legitimate technical opportunity for SPM systems to be used in a valuable, productive way. I simply mean that there often is a disconnect between those that specify and purchase these systems, and those that are responsible to operate them.

What evidence do I have?

Let me offer two pieces of evidence – direct experience and indirect conclusion.

In our personal experience with development of the USCG system, we found a real hurdle to implementation of the SPM system in the “culture” of the ship drivers. They were personally responsible for a highly valuable asset and they took pride in a personal interaction with the control of the ship. They did not trust that a “black box” computer-based system could do what had taken them many years to learn. I personally have to honor this position – in spite of my understanding of the how SPM systems can monitor performance in a way that cannot be done by human staff. So, if the helmsman and skippers do not trust and implement the system, then there is no real solution and therefore no real problem to solve.

Indirectly, let me just point to two recent episodes in Alaska where cruise ships were believed to have traveled some distance with a whale stuck to their bow. In 2006, the Celebrity Summit arrived in port carrying a dead humpback whale, and just last week, the Sapphire Princess arrived with a dead fin whale. To my knowledge, both were outfitted with SPM systems. So what conclusion can be drawn from this? Assuming that a whale on the bow doesn’t improve the drag of a ship, one would have to believe that the speed loss or additional required power would be noticed by someone or something (the SPM system). Did the SPM systems register the change in performance? Don’t know, weren’t there – but there should have been some pick up of a drag increase of this magnitude. Was the speed low enough so that this added drag was not noticeable? Perhaps, but then the SPM system is really not needed. Was it noticed and ignored? We can’t know, but it doesn’t matter – the change in performance was not significant enough to demand some action or response.

SPM systems might make management “feel good” but we would have to question if, due to no fault of the system itself, they were useful in functionally identifying performance issues that resulted in a responsive action. If the culture onboard has a skepticism that prohibits its effective use, what’s the point of having it? Likewise, if a whale doesn’t get your attention, can we honestly say that SPM systems are effectively integrated into the ship’s operation?

SPM systems are technically valid ways to reduce fuel rate and improve ship operation. But, they are just a “feel good” opportunity for “green marketing” if not properly employed.

References

Macesker, B., et al, “Evaluation/Validation of an Electronic Engine Speed Pilot on the USCGC TAMPA (WMEC 902)”, U.S. Coast Guard Research and Development Center, Report CG-D-04-99, 1999.

MacPherson, D.M., “The Implications of Adaptive Speed Management (ASM) for Fast Ferries”, 15th Fast Ferry International Conference, Boston, 1999

Time trial racing – deep water versus shallow water

Miscellaneous Musings from the Technical Director

I received an interesting email yesterday, and I thought I would share my reply with our blog readers. It comes from a speed record holder “kite surfer”.

In the world of speed sailing, kite surfers can sail in very shallow water (down to less than 10 cm), which gives us very flat water without chop. Last year the sailing world changed the rules to force us into deeper water saying that using shallow water was using ground effect and reducing drag which is cheating, but reading your report it seems the opposite is true for displacement hulls. Do the same rules apply to planing hulls that are pushing 50 knots in water depths less than half of the beam of the board?  

This new rule is pushing us into choppier water and slowing us down and not letting us show our true potential to sail as fast as possible. We are trying to put a case together (if there is one) to challenge this rule that – as far as a bunch of surfer types can make out – is a bit unfair to us. 

So the question I’m asking is “do we get an advantage in terms of speed from sailing in very shallow water with a planing hull in terms of ground effect or is it a disadvantage like your report states for displacement hulls”?

(Edited for space.)

First, my hat is off to anyone going 50 knots on a small board. I don’t have the same “need for speed”, but I’m impressed none-the-less…

The Rules Committee is making a correct technical statement about shallow water drag, but there are other aspects of the physics of operation in shallow water that may be on your side. Let’s first consider the general hydrodynamics of shallow water drag.

The attached plot [Hofman 2000] illustrates the basic principles of added drag due to shallow water. A non-dimensional depth-based speed parameter is on the X axis (usually noted as FNH, but shown here as FL), and a ratio of drag in shallow water to that in deep water is on the Y axis. You can see how shallow water drag increases rapidly as it approaches the “critical speed”, after which it just as rapidly drops off and produces negative added drag. Displacement hulls generally stay in the “sub-critical region” as they typically don’t have the necessary thrust-making “oomph” to get past the critical region drag hump. This is the mode that was described in the paper you read from our Knowledge Library. Planing hulls, however, typically can get past the critical hump, at which point shallow water becomes beneficial.

How beneficial? Let’s refer to another plot specifically for a planing hull [Khattab 1999].

You should be able to identify the various zones – sub-critical (0 to 0.9 m/s), critical (0.9 to 1.6 m/s), and super-critical (1.6+ m/s). You can also see that the super-critical (planing) drag benefit of shallow versus deep water is indeed significant.

However, in the context of making a case for racing in shallow water, I would acknowledge the drag benefit and ask “so what”? It would seem to me that one critical aspect of any type of time trial racing is uniformity in the venue. For example, you can also see from the plot that the planing mode benefit is affected to a much smaller degree by water depth or speed – the curve shapes in shallow water follow the deep water drag curve, and the drag offset is relatively uniform regardless of the “shallowness” of the water.

I would also have to question if there were any other performance benefits by running at an inland location (where you would find shallow water), rather than offshore. For example, does this give you more consistent wind velocity and direction? You also mentioned surface chop, which I would suggest has an even bigger effect on planing drag than shallow water, especially at 50 knots.

So, while I think the Rules Committee has a legitimate point to want to have uniformity in water depth (and the venue in general), it seems that the better solution is to do exactly the opposite of what they are suggesting. By requiring racing in shallow water, rather than in deep water offshore, it seems that you gain uniformity not only in the hydrodynamic aspects of added drag, but also in wind (your propulsion) and other potential variables (chop). Good luck.

References

Hofman, M. and Kozarski, V., “Shallow Water Resistance Charts for Preliminary Vessel Design”, International Shipbuilding Progress, Vol 47, No 449, April 2000

Khattab, O., “Investigation of the Behaviour of Planing Hull Forms in Shallow Waters”, International Conference Hydrodynamics of High Speed Craft, 1999

1-800-IGNORE-ME

Miscellaneous Musings from the Technical Director

When we get into work each morning, one of our first tasks is to check voice mail for the hours that the office has been closed. I must say that I am increasingly frustrated by the rapid and clipped messages that are often left for us.

My rule for such things is simple – if I want to be sure that someone will call me back, it is incumbent upon me to make sure that the information I leave is clear and complete. All-too-often, this is not the case. I’m sure you know what I mean…

Think about how salespeople deliver this information. Remember those annoying television ads that repeat a “1-800″ contact number a dozen times? Annoying perhaps, but there is no confusion about the number to call.

You won’t find salespeople rushing through a message or a contact number. This is the sole avenue to further communication. It is a valuable part of their sales process. So why do we discount the value in our voice mail messages for technical communication? We want your voice mail message – please don’t make it easy for us to ignore you.

Dog sledding as a model for team management

Miscellaneous Musings from the Technical Director

I am not about to cast myself as a business “self-help” guru. Those guys crack me up. If they had the business savvy to be successful, why are they flogging “how-to-succeed-in-business” books and audio tapes. They are good at selling books and tapes, but I’m not sure how much one can glean from them otherwise. Having said that, I had an opportunity to witness “corporate effort” (with a small “c”) in a very primal form – dog sledding.

Our family had been wanting to dog sled for many years, and never really had a good chance to do so. This year, we went up to northern New Hampshire and spent an afternoon with the Muddy Paws Sled Dog Kennel. This outfit takes in rescued dogs of proper breed with dog sledding experience, and offers drives of various duration. They opened especially for us that day, and we had the place to ourselves. The dogs were wonderful, and the new puppies cute as anything. But I digress…

To give you a sense of our dog team, we had eight dogs set up in four pairs, starting with a lead dog and his partner. The lead dog took the audible instructions from the musher (driver) and managed the team’s direction. His partner had the responsibility of keeping him in line. Lead dogs sometimes get a little full of themselves and would choose their own route if left to their own designs. The lead partner would nudge, block, and even nip, the lead dog to make sure that he followed through on the musher’s command.

The following six dogs were the real pullers, with the steadiest runners forward and the strongest at the back. We had two Malamute-cross dogs as the major traction for our sled, and they had a calm strength that was almost elegant. They were a real contrast to the more anxious and flamboyant lead dogs. Our little group was quite a collection of different roles and strengths – each necessary for the success of the group, and each relatively useless without the other.

The real eye-opener for me was how the “need to work” changed the personalities and motivation of the dogs. We had to stop to help another sled get turned around, and the dogs momentarily lost their focus. We wound up with a confrontation between the lead dog and at least one other dog that erupted into an eight-dog teeth-and-fur snarling mess. The musher got things untangled, but there were minor injuries to two of the dogs. After resetting the group, we were back on our way.

Almost immediately, the whole tenor of the team changed as the musher started to get the sled moving faster, allowing the dogs to work with focus. The cadence became steady, and you could see a change in the body posture of every member of the team. Heads were up, focused forward. Commands were precisely followed. There was a palpable joy in their movement. The team and musher were working as one unit, not as nine individuals.

I was very impressed. The lessons to me were refreshingly simple.

• One cannot succeed alone. I cannot achieve my objectives alone. I need my team.
• Every team needs diversity of talents and strengths. The core of HydroComp’s management is a partnership of engineer and business administrator. Our team is likewise built of individuals with different education and experience. We have also found that our interns – both engineering and business – offer creative insight and energy.
• There is focus when the purpose for the work is known by all team members. My management style regarding the “big picture” has not always been inclusive, to my detriment. The engineer in me wants to retain control of processes as much as I can. We lost a good employee some years ago, as I unknowingly did not include him in the broad vision of the purpose for the work he was doing. Reflecting on this, I believe that he felt a bit like a tool in my toolbox, rather than a full member of the team. It was a humbling lesson for me to learn.
• The need to work and produce is fundamental. “Busy work” is rarely worth the effort. Good team members want to be productive and see their work valued by management, customers, and clients.

New "Marine Performance Technology Exchange" posted

You can download our latest issue of the Marine Performance Technology Exchange from the Knowledge Library on our web site. The principal article is about the “Contribution of a nozzle in ducted propeller performance”. Just look for the November 2008 issue.