Description This Campaign period was from 1 November 1969 to 30 April 1970. The generally good performance of the Vietnamese Navy during the allied sweep into Cambodia motivated the transfer of significant operational responsibilities to the Vietnamese. The barrier along the Cambodian border was turned over to the Vietnamese Navy in March 1970, which renamed the operation Tran Hung Dao I. In May, Giant Slingshot and Sea Tiger became Tran Hung Dao II and Tran Hung Dao VII. The allied navies also launched Operation Blue Shark, a seven-month effort designed to strike at the Viet Cong command, communication, and logistics network (or infrastructure) in the mangrove swamps at the mouth of the Mekong River system, on the river islands, and along the river banks all the way to the Cambodian border. Coastal Surveillance Force PCFs landed SEALs and LDNN for swift, deadly attacks on the usually surprised enemy. The units often followed up on intelligence gathered by Naval Intelligence Liaison Officers (NILO) assigned to many of South Vietnam's provinces and operational areas.
Coinciding with the turnover of river and coastal fighting vessels in 1969 and 1970, the Navy transferred many of the bases from which they operated. The first change of command occurred at My Tho in November 1969. Then, in the last three months of 1970, COMNAVFORV placed the Phu Cuong, Long Binh, Kien An, Chau Doc, Tan Chau, and Ha Tien Operating Bases under Vietnamese control. The transfer of Sa Dec and Chu Lai the following spring completed the process. During this same period, the Vietnamese Navy took over the six Advanced Tactical Support Bases established on the Vam Co Dong and Vam Co Tay Rivers for the Giant Slingshot operation and two more on the Cua Viet River in I Corps. In addition, the allied naval service assumed control of the harbor defense posts of the Stable Door effort, the three existing coastal radar sites, and Market Time's coastal surveillance centers.
Meanwhile, the Navy deployed Seabee detachments throughout South Vietnam to construct logistic facilities at new and existing bases. Once the Seabees completed this work and U.S. leaders felt the Vietnamese could totally support their combat units, the Americans transferred the bases to their allies. In this manner, beginning in the spring of 1971, Rear Admiral Robert S. Salzer, the new COMNAVFORV, relinquished control of Cat Lo and An Thoi, two of seven primary Logistic Support Bases that provided allied naval forces with major vessel overhauls and other supply assistance. In the same period, the Vietnamese took charge of Ben Luc and Rach Soi, two secondary or Intermediate Support Bases. These installations handled minor craft overhauls and provided units with maintenance, administrative, financial, and supply support. The next incremental transfer occurred in September when the Dong Tam Logistic Support Base and eight Intermediate Support Bases were Vietnamized.