What Do You Do If You Have A Seaplane Too Heavy With Fuel And Cargo To Take Off?

attach it to a bigger seaplane!

the aircraft is used when landing a large normal transport sea plane is to big to land in a small area, say a bay or a lake,

the aircraft was know as the Short-Mayo Composite,

and by all accounts successful in what it was designed for, 

if you have time grab a coffee and watch this video, what a totally mad out of the box idea, but it worked!