Our holding tank is about 10 gallons and is located under the
starboard settee. The connection for the vent hose is at the
forward end of the tank. The hose runs back to an outlet about 3
feet aft and 2 feet above the tank. This gives a rather curvy,
mostly horizontal hose run of about 6 feet. Air can enter and
leave the tank for filling and emptying, but there isn't any real
"air circulation" to prevent odors. It looks like there might be
room to put a new connection at the aft corner of the tank which
would shorten the hose run by 2.5 to 3 feet. The tank is
fiberglass or some kind of very hard plastic. (It's been painted
so it's difficult to tell what it's made from.) We think the tank
is probably 20 years old and was custom made for the boat when it
was built. The vent hose appears to be 1/2 inch ID.

So here are my questions:
1. Would shortening the hose by this amount make any real
difference in the air circulation?
2. Would modifying the tank cause any problems with its
structural integrity?
3. Assuming the answer to 1 is "yes" and 2 is "no", how should we
go about adding the new connector and removing the old one?

Thanks

Cindy