Below is the list of tables from the database along with their columns and datatype. Need to generate an accurate SQL query for the question.
Only use the columns present in the respective table. Only use the columns which are required to generate the SQL query. Only use table joins if required and not otherwise.

### Tables ###
TABLE: CREATE TABLE table_52766 ( "Name" text, "Pennant" text, "Builder" text, "Laid Down" text, "Launched" text, "Commissioned" text )

### Question ###
what is the launched date when the builder is john brown, clydebank?

### Accurate SQL ###

SELECT "Launched" FROM table_52766 WHERE "Builder" = 'john brown, clydebank'