Brian D wrote:
How about this one:

http://www.shipstore.com/ss/html/AFI/AFI10104.html

No reservoir tank required. Small pump. Puts out 126 db at 1 meter
and
meets all International Maritime Organization requirements for
anti-collision horns on boats less than 20 meters (65') in length.
Price is
reasonable at approx. $150.

As I understood it, this is exactly the type that the original poster
is seeking a replacement for! 126dB @ 1 meter is also certainly an
exaggeration for this horn. Those little vane air compressors top out
at about 5-7 psi, which is not going to get you to 126dB. I believe
that this same horn can probably achieve 126dB @ 1m, but only if run
from a small air tank with higher supply pressure.

-Adam