What do you call jokes

What do you call a Titan who can't swim?

Titanic!

Imagine the Titanic with a lisp. It would be unthinkable. My version is imagine the Titanic with a lisp, it would be unsinkable.

What did the front half of the Titanic say to the other half when it hit the iceberg? I'm breaking up with you.

What do you call someone with notorious special needs and an extra chromosome?

The double trouble.