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_name_51 (horsepowers INTEGER, year VARCHAR, tonnage VARCHAR)

### Question ###
How many Horsepowers have a Year smaller than 1974, and a Tonnage of 4437?

### Accurate SQL ###

SELECT SUM(horsepowers) FROM table_name_51 WHERE year < 1974 AND tonnage = 4437