On Wed, 26 Mar 2014 19:51:26 -0700 (PDT), "Peter E."
wrote:

The brass grill in these photos is 12 x 8 x 2.1 cm.

http://easthope.ca/BrassVent0.png
http://easthope.ca/BrassVent2.png

Please explain how it should be installed. Should it be on a deck or on a bulkhead? Where is it typically located and oriented?

Is there a net accessible photo of something similar and installed properly?

Thanks, ... Peter E.

That is a cover for the raw water intake for your engine. It goes on
the bottom of the boat covering the water inlet.

See
http://www.westmarine.com/metal-plum...-hull--6606842
for a similar device which includes the thru hull fitting, that will
give you an idea of how it is used.
--
Cheers,

Bruce in Bangkok