How to get Lumenade
After going to Lichlett and talking to the scientist he will tell you to go to the Tidesway Beaches and he mentions the lighthouse keeper.
Go to the lighthouse there and talk to the lighthouse keeper when it’s night, select the first dialogue option and give him some ancient junk. It will appear as a completely black item in your cargo inventory.
Ancient junk can be found in the vaults of Skull Castles.
Lighthouse keepers will give you laminate for every piece of ancient junk you give them.
How to use Lumenade
Once you get some Lumenade, you can take it to the scientist wherever they appear, such as the Tidesway Beaches.
Talk to him and the research menu will appear, where you can spend your lemonade to unlock new blueprints that can be made at the Ship Shape Shop Merchant.