In the four years following the cessation of hostilities with the Manticoran Alliance, Bolthole's scientists succeeded in developing LAC carriers, modern-standard light attack crafts and pod-laying superdreadnoughts, among other systems.
Despite their best efforts, the intelligence services of the Manticoran Alliance were unable to discover its exact location until the end of the Second Havenite-Manticoran War. (HH11) It was located in a system on the far side of the Haven Sector with a population of hundreds of millions. (infodump)
After the total destruction of HMSS Hephaestus, HMSS Vulcan, and HMSS Weyland and the formation of the Grand Alliance, Bolthole became the key R&D facility for the Alliance and its researchers. Admiral Sonja Hemphill and most of the Weyland's surviving researchers departed from Manticore to Bolthole in or around July 1922 PD so that Hemphill and her staff could combine forces with Shannon Foraker to explore further hardware development. The facility would also be the Alliance's primary shipyard. (HH13)
- David Weber's comment on the origin of Bolthole and the BLS in the Infodump