But the workers are from all around the area, they are not live inside Changxin island, right?
I think it's hard to keep up with the schedule when the entire Shanghai is in panic mode.
I don't know if you are living in China and have been in industrial areas in China, if you are then you should know that generally all factories provide dormitories for staff and workers inside factory compound or in closeby buildings. I see no difference here in Changxin island.
Firstly Changxin island has no direct road link to Shanghai city proper (Pudong and Puxi area) , its only road link is by a bridge to Chongmin island to the North. Chongmin island is linked to Shanghai Puxi Shengqiao town via underwater highway tunnel across the Changjiang river aka Yangtze river aka Yanzijiang. Which means Changxin island is indirectly linked to Puxi via Chongmin island, but there is no direct link to Pudong.
Second there are large highrise housing areas on the Changxin island, with recreational sports complexes clearly visible on Google Earth images. I am sure these housing complexes can accommodate all workers and staff of all shipyards on the island. There is no need to drive for hours from Pudong to the shipyard.
Is there any scheduled ferry service from Pudong to the shipyard, I don't know but I dare to speculate there is none because there are no towns on the island, some farmers yes but no town folks to justify a ferry service.
So tonight lockdown on Pudong is going to be ended at 12.00 midnight, thereafter Puxi will be locked down until testings on its residents are completed, probably within 2 weeks.
In short, lockdown on Puxi and Pudong should have minmum effect on Changxin island, unless the shipyard management decided to stop work by own initiative or by order of city government.