According to China Daily, Chinese shipyards saw their orders shrink by 41 % in 2008. A further drop of 48-66 % is expected for 2009, as well as cancellations amounting to 15-25 % of existing orders.
China had 3,050 shipyards (as of late 2006). The largest, China State Shipbuilding Company, says it has 8.8 % of the entire world's ship-building order-book (in total, China claims to have a market-share of nearly 50 % measured by order-book-size).
China's ship-yards focus on bulk freighters (such as the ones hauling iron ore from Australia to China), which make up 66 % of orders. Oil tankers account for 18 % of orders, container vessels for only 9 %.
Presumably, current production is still going strong due to the order backlog, and will only start dropping off later this year or 2010. However, the mid-term outlook is certainly grim: Massive overcapacity implies zero new demand for all standard-type vessels.
I couldn't find industry revenue figures. However, China Daily reports the industry's 2008 net profits as 28 bn RMB. Assuming a profit margin <10 %, revenues would have been >300 bn RMB (>1.5 % of China's GDP).
There certainly won't be any more profits going forward. Nor will there be many jobs left.