[racket] hash table confusion

I have a hash table (created by using make-hash) where the key is a
struct. This seems to work fine although the documentation says
   The make-hash procedure creates a table where keys are compared with
   equal?,...

and it seems that equal? gives #f if I compare two structs having the
same contents:


(struct cpd (x y))

(define C1 (cpd 1 "bla"))
(define C2 (cpd 1 "bla"))

(equal? C1 C2)
#f


Why does my hash table work fine? In my hash handling I'm using
make-hash, hash-ref!, hash-set!, hash-for-each.

-- 
Manfred