SCB.503.71 Mine Countermeasures Ship (MCS)
Jane's 1968-69 says that two new construction MCS were planned and JFS 1969-70 says they were planned for construction in Fiscal Years 1971-72.
However, Jane's 1970-71 says.
The US Navy has been forced to abandon plans to increase its mine countermeasures capability. The planned 16 new-design ocean minesweepers (MSO) and two new mine countermeasures ships (MCS) addressed in previous editions have been dropped.
I don't know anything about his design (it's not mentioned in the relevant Friedman book) but my guess is that it got as far as receiving a SCB number and the next number in the sequence is SCB.503.
At the time the USN had 2 MCS, Catskill and Ozark which were designed as large minelayers (CM), re-designated transports (AP) and completed as vehicle landing ships (LSV). They were again re-designated Mine Warfare Command Ships (MCS) in 1955; and to Mine Countermeasures Support Ships (MCS) on 25.08.60 and finally to Mine Countermeasures Ship on 14.08.68.
JFS 1970-71 said.
These are the first ships to be totally converted to carry the support and minesweeping launches and helicopters. Heretofore this role was performed by modified tank and dock landing ships. The Catskill and Ozark are fitted with navigation and communications equipment for vectoring minesweeping launches and helicopters; also fitted with command and communications facilities for mine force commander and staff. They are intended for use in support of amphibious operations.
Catskill was struck from the Navy List on 01.04.61 and Ozark on 01.09.61, but were reinstated on 01.40.63 (Ozark) and 01.06.64 (Catskill) and converted to mine warfare configuration. They re-commissioned on 06.10.67 and 24.06.66 respectively. However, not for long: Catskill was decommissioned & struck from the Navy List on 01.12.70; Ozark was decommissioned & struck from the Navy List on 01.04.74.
That meant the USN didn't have a requirement for ships of the MCS type. LPH-12 Inchon was re-designated MCS-12 on 01.03.95 and then and commenced a 15-month conversion/overhaul. I think editions of Jane's from that period said that the USN had a requirement for 2 ships of this type. I can't prove it, but suspect that the 2 new MCS (that may have been SCB.503) planned for the early 1970s may have been modified Iwo Jimas in a similar way to the Blue Ridge class LCCs using the hull and machinery of the Iwo Jima class.
