Table: comus_corvette
Columns: ship
laid_down
builder
engine_builder
launched
completed
disposition
fate

Question: When was the Carysfort launched?
SQL: SELECT "launched" FROM comus_corvette WHERE "ship" = 'Carysfort'

Question: When was the stokers' training ship launched?
SQL: SELECT "launched" FROM comus_corvette WHERE "disposition" = 'Stokers'' training ship'

Question: How many ships were named Carysfort?
SQL: SELECT COUNT("completed") FROM comus_corvette WHERE "ship" = 'Carysfort'