Toward an expanded Measure of Merit

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Within Systems Engineering much effort is devoted to the development of Figures of Merit. In a textbook case of naval architecture the measure merit is economic, perhaps required freight rate (RFR).

This measure of merit is the parameter that is used to choose between options: Pick the ship with the best RFR. But all parties will admit that the RFR does not capture all elements of the ship’s requirements. Instead, some requirements are taken to be sine qua non, and are thus valueless as discriminators. Examples might include complying with applicable laws, or having adequate structural integrity.

But let us consider further these fundamentals. Take something as straightforward as structural integrity: This term means the ability of the structure to withstand the sea loads. But what sea loads, and for how long? Shall we design for the extreme wave event? Shall we design for a 40 year life, or shall we assume some mid-term refurbishment? Clearly the answers to these questions will have some impact upon the ship economics.

In warship design the measure of effectiveness is already extremely complex, and adding esoteric elements just makes the problem worse. But I opine that warship analyses also have higher budgets and more rigor, and thus could be best prepared for trying to tackle these items.

Conventional wisdom is that this impact is so small as to make it not worth consideration. But how many of us have ever taken the time to prove this, even once? And might not a long sum of individually-negligible considerations add up to be a discriminator? But I digress. Obviously a consideration of structural integrity could be folded into an economic measure of merit. It would be tedious and it might be insignificant but we all know how to do it.

But now let me return to the concept of a measure of merit, and focus upon the word “merit.” Synonyms for “merit” might include “goodness” and “quality.” So let’s try substituting the term “measure of quality” for “ measure of merit.” Now we find that we are practically forced to widen our tent. What are the things that contribute to quality? Economics is one them, and it is one that is particularly tractable and calculable, but it is certainly not the only element that goes into making a fine ship.

Here is a list – off the top of the author’s head – of elements that contribute to the quality of a ship. Note that the list is organized according to the perspectives of different stakeholders.

For the Owner, a good ship is:

  • Economic – she makes money
  • Reliable
  • Doesn’t get sued
  • Easy to man
  • Makes her owner proud

For the seaman a good ship is:

  • Seakindly
  • Easy to maintain
  • Easy to operate
  • Comfortably arranged
  • Reliable
  • Makes her crew proud

For an insurer, a good ship:

  • Pays regularly (makes money)
  • Doesn’t generate claims (reliable, reliably manned, etc.)
  • Doesn’t embarrass the Company

But why stop there? Are we not, as naval architects, each of us committed to the success of all ships? Indeed as citizens of the planet does not each one of us have an interest in, say, the environmental impact, or even the economic impact in terms of our quality of life?

My purpose in this essay is to argue that we should use as broad a measure of Quality as we can, and further to argue that this is possible.

In taking this position I do NOT mean to argue that we are producing low-quality ships. But I do mean that we are producing them tacitly, and not as a result of engineering rigor, except in the case of a few top-order parameters.

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