Larry Penberthy by profession was an engineer*, and a very successful one. So when he turned his mind to the issues of climbing his discerning mind analyzed everything-- from the gear used, to the human body itself. Inevitably, his inquiries led to TESTING.

Penberthy was best known for his iconoclastic testing of standard "hard" gear such as ice axes and climber's helmets, but his interests did not stop there, and in this image from July of 1972, we find him at 10,000 feet on the west side of Mt. Rainier in his trademark white shirt and dark slacks, puffing away on a makeshift rock treadmill, all hooked up to medical gear! What's going on? Note the fellow dressed warmly in the puffy down parka-- he's a physician from California whose interest is in Acute Mountain Sickness (AMS). Penberthy is his guinea pig, and is 56 years old... If one looks closely, on Penberthy's one arm is a blood pressure cuff, and in that hand a heart monitor; in the other hand is a counter, counting the number of steps he's taken on the rocks. Meanwhile, the doctor is watching a wristwatch and recording results in his log book. Real fun, and much grist for Penberthy's next issue of his beloved MSR NEWSLETTER. (see image below from October 1968 newsletter, compliments Mr. Ed Tieman).

* Penberthy was a 1936 graduate of the University of Puget Sound in Tacoma. Interestingly, another 1936 graduate was John Lea. In the early 1970s, Mr. Lea and his younger brother Jim Lea were two of the three* founding fathers of the Thermarest Air Mattress (incorporated as Cascade Designs in 1972). Of even more interest is the acquisition of MSR by Cascade Designs in 2001, which was also the year of Penberthy's death. (*the third founder was John Burroughs, a contributor to my book about MSR)

Please Note: All Material below, and in all my "History of Gear" webpages, is copyrighted, and no usage of my material is permitted unless explicit permission is granted by me, Bruce B. Johnson, owner of Some of the material below is derived from interviews and/or correspondence with Mr. Ed Tieman, climber and former MSR employee from the early 1970s and 80s...... Editors: Please contact me at if you have interest in publishing....Others: if you were involved with one of the old-line, vintage gear companies and have a story to tell in these pages, please contact me soon.C*


A fellow Engineer and Iconoclast in the History of Gear has always been Mr. Jack Stephenson of Stephenson's Warmlite... Both men have had a reputation among their peers and customers of being both brillant and occasionally less than easy to get along with; in fact, Stephenson admiringly told me, "Larry is as stubborn as me." As of 2016, Stephenson continues to produce his ultralight tents and sleeping bags for a small, custom market of discerning customers.

Continue to Warmlite pages


Final Words about Penberthy and MSR: Penberthy died at age 85 on Nov. 24, 2001. MSR was sold to REI in 1981, and Cascade Designs has owned it since 2001



Main Page: Essays and pictures about the Pioneers of the Outdoor Gear Revolution, 1935-The Present

Back to MSR- page one; please note that I've now completed my book about the early history of MSR under Larry Penberthy and it is available for sale.


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Page last revised 11/03/2023