*It is highly likely that the [[Z1]] unlock quest must be cleared before [[I-8]] can construct Z3. Due to low sample size and lack of pictorial evidence other than collected construction data, avoid using her unless you've lost all your German ships after completing the quest.
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*It is highly likely that the [[Z1]] unlock quest must be cleared before [[I-8]] can construct Z3. There is only a small amount of evidence for this, but it's generally advisable to simply use Z1.