We have made every kind of shell and tube heat exchanger imaginable, but this depropanizer overhead condenser was interesting. Bound for Alberta, ABSA made an unusual request. They asked us to verify the tubesheet thickness using long hand calculations. Concerned we would lose valuable production time, we called the (mostly) retired engineer (and EM owner) Peter Corless out of retirement. We put him straight to work on the calculations. Over several days and after some involved conversation the calculations were complete. Once approved production of the long and slender heat exchanger was full throttle. Weighing more than 75,000 lbs and extending nearly 70′ long this depropanizer overhead condenser was as unwieldy as it was unique and challenging.