[ ] Four Ships over Four Years (-16 Industry)
Starting at 35 Industry, this would leave us with 19 unused Industry, giving +15.2 Industry over four years. Total afterwards, with the Stingray construction also finishing, is (16+19+15+20) 70 Industry.
[ ] Six Ships over Four Years (-24 Industry)
This would leave us with 11 Industry, giving +8.8 Industry over four years. Total afterwards is (24+11+8+20) 63 Industry.
[ ] Eight Ships over Four Years (-32 Industry)
This would leave us with 3 Industry, giving +2.4 Industry after four years. Total afterwards is (32+3+2+20) 57 Industry.