Me: [pointing] What’s that?
Brother: A concrete ship. Used to be a tourist attraction — had an arcade, snack bar, that sort of thing.
Me: And it’s made of concrete?
Brother: [wry smile] Yes.
Me: Err, were they surprised when it sank?
Read more about the S. S. Palo Alto, which really was a concrete ship… one of twelve built during WWI when steel was scarce.
See also the various aerial photos of the ship at the multiply-wondrous californiacoastline.org website.