When the maximal number of elements that may be inserted into a container is not known in advance, the container needs to grow dynamically. Growable containers are most frequently implemented on top of lists or vectors, yet both are inefficient in terms of space and time usage. We investigate the implementation of OCaml of sequence data structures that store their elements in fixed-capacity arrays, called chunks. For sequences of several thousand elements, we show that our chunked-based sequence data structures save a lot of memory and may deliver better performance than classic container data structures.