The system did not perform as effectively as expected, however. This was due to two major defects in the design. The riveted joint that connected the interior torpedo bulkhead to the bottom of the hull was not strong enough to sustain the tremendous shear loadings associated with direct contact explosions. The joints failed even in cases of non-contact explosions; this prevented the hollow drum from collapsing as designed and resulted in massive flooding. The fineness of the hull shape prevented the 3800 mm thickness from being maintained for the entire central citadel; the width of the drum was reduced significantly abreast of the main battery, down to . The ability of the drum to absorb explosive shock correspondingly fell in relation to its size.