Original: A number of 6 m Trailer Sailers sailed on Lake Eyre in 1975 , 1976 and 1984 when the flood depth reached 3 â '' 6 m ( 10 â '' 20 ft ) .
Simplified: A number of 6 m Trailer Sailers sailed on Lake Eyre in 1975 , 1976 and 1984 when the flood depth reached 3 â '' 6 m.