Five years ago today we launched Station HYPO. We want to thank you for helping us celebrate the past, present, and future of Navy Cryptology.
Our first post follows.
The Team at Station HYPO
Today, we proudly announce the establishment of Station HYPO. The vision of this blog is to post quality content that celebrates the history of Naval Cryptology, keeps members of the Cryptologic community up to date on current events and development, and sparks discussion about our future.
Why Station HYPO?
During WWII Station HYPO played a significant role by providing time-sensitive intelligence to Admiral Nimitz and his commanders, giving them the tactical advantage they needed to defeat the Japanese Imperial fleet. The support provided by Station HYPO was so reliable that Admiral Nimitz compared this special type of intelligence to having an additional fleet of ships. We believe the same innovation, competence and collective ownership that permeated Station HYPO 75 years ago exists in our Cryptologic Enlisted Sailors and Information Warfare Officers today!
Station HYPO began in 1938, three years before the attack on Pearl Harbor, as the Hawaiian Decrypting Unit/Communication Intelligence Unit at the Pearl Harbor Navy Yard administration building. In June 1941, five months before the attack on Pearl Harbor, CAPT Safford head of OP-20G in Washington DC assigned then LCDR Rochefort as the Station HYPO Officer-In-Charge. On December 1 1941, under the charge of LCDR Rochefort, the Decrypting Unit/Communication Intelligence Unit moved from the second floor of the Administration Building to the basement. This was partly for security reasons, because the basement was sealed off from the rest of the building, but also to accommodate a growing staff, which had doubled from 23 in June to 47 in December. Later in the same month, after the attack on Pearl Harbor, the unit was re-designated as the Combat Intelligence Unit and was given the classified code name Station HYPO. At the time, HYPO was the phonetic code for “H” and was in direct reference to He’eia, Hawaii, the station’s location.
In April 1943, Station HYPO moved from the Pearl Harbor Navy Yard into a new two-story building at Makalapa, adjacent to the Commander-in-Chief Pacific Fleet (CINCPACFLT) headquarters where it remained for the duration of WWII. In 1945 it became known as Naval Security Group Pacific and moved to the fourth floor building of the CINCPACFLT headquarters building at Makalapa until 1951.
Some of Station HYPO’s WWII contributions include, but not limited to:
- Established the Japanese Imperial Fleet organizational structure (Naval Order of Battle) and Command Control structure.
- Discovered that the Japanese Imperial Fleet radically reorganized days before the attack on Pearl Harbor and was attempting Radio Deception.
- Provided time-sensitive intelligence to Commander Submarine Pacific that resulted in the first sinking of a Japanese man of war (submarine) following the post Pearl Harbor attack.
- Provided intelligence on Japanese build up on their outer defense located on the Marshals and Gilbert Islands.
- Provided time-sensitive intelligence on the Japanese naval forces operating in the Coral Sea resulting in the battle of Coral Sea. The intelligence provided gave Admiral Nimitz confidence in Station HYPO efforts.
- Provided accurate time-sensitive intelligence to Admiral Nimitz regarding the planned Japanese attack on Midway Island. Admiral Nimitz repositioned his remaining aircraft carrier battle groups based on this intelligence alone.
- Provided time-sensitive intelligence on the location and movement of Admiral Isoroku Yamamoto, the Commander-in-Chief of the Combine Fleet, which resulted in the shoot down of his transport aircraft killing the Admiral. Admiral Yamamoto was responsible for the attack on Pearl Harbor.
While the efforts of a small team of bloggers will never replicate the accomplishments of Station HYPO, we proudly take its name, along with the spirit and selfless attitude instilled by CAPT Rochefort years ago. Please join us as we remember the past, recognize the present and explore the future of Naval Cryptologic community.
29 September 2020 at 12:32
You do a great job and I find the postings to be of interest. I may not always comment Mario but I appreciate the time and effort you take to post these very interesting stories each day. Thank you and I continue to look forward to your posts every day. Be well always, you and your family.
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29 September 2020 at 13:01
I was stationed at NAVSECGRU CINCPACFLT MAKALAPA from 7/68 to 6/70. It was great duty. Worked with some of the finest “O” branch guys in the Navy….TAZ
29 September 2020 at 14:54
Outstanding blog, high quality, professionally executed. Thanks for doing this and I hope to keep reading it for years to come!
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29 September 2020 at 17:45
Superb website, Mario. I read every one of the articles you post. Sometimes it’ll take 2 or 3 days before I’ll tackle one that’s way over my head, but I always read and try to understand them.
I was interested to see that in the first HYPO article it states that HYPO’s facility moved into what Rochefort’s oral history refers to as “the bomb-proof basement” from its location on the upper deck of the HQ building of the Fourteenth Naval District. Two other points are also of immediate interest: The article states the number of HYPO personnel grew from 23 in June 1941 to 47 in December. If I read this correctly, all of these people were working in the actual ComInt unit itself rather than in the field at the various intercept facilities on Oahu and elsewhere. Is this correct? If so, it’s first time I’ve ever seen 47 listed as the actual complement for personnel at HYPO in Dec. 1941.
The other point both from the above article and various other sources, is Rochefort’s rank when he came aboard at HYPO is listed as lieutenant commander. I believe he was promoted to Commander (temporary grade) upon fleeting up to become officer in charge at HYPO. The plaque on the wall above the old HYPO facility also refers to Rochefort’s rank, in this case at the time of the battle of Midway, as “Lieutenant Commander Rochefort.”
The 2 January 1942 Roberts Commission testimony of Joseph J. Rochefort printed in Part 23 of the Pearl Harbor Attack Hearings (see PHA23, pp. 673-688) gives Rochefort’s rank as Commander and not lieutenant commander.
If my analysis is correct, and have put many hours into trying to make this correct, Rochefort’s promotion to Commander was concurrent with becoming officer in charge of the Communications Intelligence Unit, a.k.a. Combat Intelligence Unit, a.k.a., Station HYPO, at Pearl Harbor in about June 1941. (I’ve seen different months listed. I’ve never found an exact date given. I have not yet examined Captain Rochefort’s personnel files or anyone else’s personnel files at the Washington Navy Yard. I certainly do plan to do so within the next two years.)
Your Station HYPO website is, by far, my favorite Internet website. I cannot thank you enough for making the information available that you and the rest of your crew put on the Station HYPO website! Happy Fifth Birthday, Mario! Ditto, to every member of the Navy-Marine Corps communications intelligence organization, past, present and future.
Andy McKane, Maunaloa, Molokai, Hawaii.
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29 September 2020 at 19:31
Mario, you have done an incredible job with this and I applaud your hard work. I love the posts, read them everyday and I’ve learned a lot. BZ
30 September 2020 at 22:25
I don’t understand why we had our CT ships floating around without any support nearby. The USS Pueblo and liberty were defenseless when they were attacked by North Korea and Israel. Was a sad day for the US.
CTO2 1962 -1968 Adak, Alaska and Kamiseya, Japan
1 October 2020 at 06:21
When I was stationed at Wahiawa from 12/56 thru 12/58 we had about 60 5-UCO covered long-haul off-island circuits and 26 each long haul and on island GORGON and PYTHON covered circuits (full dux). 3 of the on island circuits
were with MAKALAPA (CPF) and we made a courier run daily with pouches of low precedence (routine and deferred)
because we were always backlogged w/priority and higher traffic for them. When 26s came out, the ckt speed was
upped to 100WPM and that was a real god-send for us. I enjoy reading your articles each day and now at 83 yoa it
really brings back memories. Thank you and a big BRAVO ZULUI to you and your staff.