sentences:  Both attacks largely failed, but while at Zeebrugge the operation came so close to success that it took several months for the British authorities to realise that it had been unsuccessful, at Ostend the attack had ended catastrophically.Both blockships intended to close off the canal had grounded over half a mile from their intended location and been scuttled by their crews under heavy artillery and long-range small arms fire, which caused severe casualties.Thus while Zeebrugge seemed to be blocked entirely, Ostend was open wide, nullifying any success that might have been achieved at the other port.