I tried to replace mine last fall. Posted on here and also emailed C&O.
Got this page from them:
http://www.candomarineparts.com/Thruhull.html
So since I wasn't sure, I said:
"It is either PN AS-2 or PN AS-1. I will take one of each."
Didn't hear back for a bit, so I followed up and received:
"I did get it and I have been looking for the AS1. I have a bunch of the AS2s
but I haven't been able to locate the AS1. I have Sherry looking for some at
the other store. I will try to get some in here as quickly as possible.
Sorry for the delay"
That was on Thursday September 24, 2009. I haven't heard back yet which probably means they don't have it yet. I've bought lots of stuff from C&O and it's always been a great experience. Even picked up my boat at C&O II even though it wasn't bought from them - just met a customer of theirs there, bought some tackle from them and the people there were first class all the way.
I think it's just a hard part to source.
I'm sure when they have it I will hear back. I'm going to grab a couple of each just in case.
If I do, I will remember to come back here and update that they have them in stock.
Charles