The Hulk is a super freighter. It's is terribly slow, but it can carry an exceptional amount of cargo. You can build it after Trade Ministry level 25.

The huge hulk requires Trade Ministry LVL 30

The fast hulk requires PropLab 25.

When scripting the new hulks that recently became available, you can use the following as the ship types:

hulk

hulk_huge

hulk_fast