Worst Professional Blunders...

[TheCPUWizard]

SIZE=4]Wondering how many people will be willing to post some of their worst professional technology blunders...[/SIZE]
#1) While designing a targeting system for the main gun of a Frigate....

We were on sea trials, a videeo camera was loadede into the main gun, and drone aircraft were sent flying around. If the drone stayed in the center of the cross hairs, all was good.

Afrter about 2 hours, the ship suddenly reverberated with a heave metal on metal BANG, that rattles the entire ship. The was mild panic, since this was the first time the ship was out at sea, and anything upto and including a hull fracture could have been the cause. Nothing was found.

About an hour later, the same thing, less panic, but more concern. Again nothing was found.

Another 1.5 hours passed, and it happened again. This time a sailor saw the main gun move from the targed possition, slam down against the bottom stop, slam up agains the top stop, then return to tracking the target.

The cause was found...but why???

Looking at some of the machine logs the reason was determined. A gun must correct for "actual" wind. But the ships sensors (anonemeters) measure relative wind. You need to subtract out the ships speed and heading (the induced wind). Now when dealing with angular measurements, you typically use either 0-360 or +/-180. I had chosen the latter.

There was a filter algorythm that smoothed the data. If the wind was coming in over the stern (very rare), then sometimes you would get numbers in the 170-179.99 range other times in the -179.99 to -170 range.

Now what happens if you average these two numbers. YOU GET A NUMBER NEAR ZERO.

The computer interpreted this as an instant hange from a tail wind to a head wind!. The gun went berserk......

[June 1991 abord an RNLN M-Class Frigate]