leaking around exhaust

[iridea96xp]

ive noticed that water was in the hull of boat and realized it was leaking were
the 2 pipes join on a xp the 10mm stud was broke how do i get it out
pleaes help

 

[JPX]

Exhaust pipe hardware vibrating loose is definitely a problem. And that stud is in the least convenient place possible to extract it. But what you might end up with is removing the pipe, the curve AND the exhaust manifold to get it removed.