not come into production until a few months before the end of the war, and it helped to swell surplus capacity. The result was that shipping in the 1920s was under a cloud of shipyard overcapacity, making it difficult to disentangle the cycles. The index shows little change over the 20 years, with just three short peaks and two lengthy troughs. The average length of cycle was 7.8 years. Contemporary records show that the first cyclical trough started in 1921 and continued until 1925. During this period the market was weak, though this is not fully reflected in the annual statistics. In 1926 there was a brief boom, triggered by the coalminers’ strike in the UK, plus a revival in business activity. By the end of 1927 rates were slipping again and the market moved into a seven-year trough, one of the longest on record.