Page 2 of the operator's manual (pub. no. 36906) has a diagram showing this.
If this is not the manual you have, the zinc is on the side with the oil
dipstick, left and up a bit, it screws in to the heat exchanger (cylinder
with three black tubes) from 8 o'clock to 2 o'clock.

Westerbeke recommends you check this every month, replace when 50% depleted,
varies with use.

Hope this helps
Cheers.
"Jon Klapper" wrote in message
...

Stupid Manual!!!! It says to replace the zinc in the heat exchanger
every year. The $#!!$ thing probably hasn't been replaced in ten years
and I can't find it. The box of junk and odd parts that came with the
boat have two different size bronze plugs with zinc rods cast into
them. They obviously screw in somewhere but I'll be damned if I can
find them. One old plug with a corroded zinc has a bit of red paint on
it and looks like its on the outside somewhere. Is it possible its
inside the heat exchanger? Should I pull the endcap?? Should I just
sink the damned boat and collect the insurance?

Anybody got a clue????