Well in the process of buying it the owner said it "needed attention" and after buying said it was broken.
My impression is the rod has snapped and from what I've read that's fairly common.
I'm aware there's a drain-plug type thingy under the step as a vent, but this 'center valve' is under the water-line and is not an air vent. It seems it's on a threaded rod and you tighten it up to seal 2 holes on the underside of the hull. And presumably loosen it to let water in.
Might want to check out page 13 of the '95 and '96 manuals."
That doesn't mention anything about the ballast, but perhaps you mean page 12 where it mentions the water should be no more than 3 inches below the drain-plug hole? Yes, but that doesn't help me understand why it seems to have TWO ballast valves.
On page 15 it shows a cut-away view of the center valve. It seems it's right next to the finger-poking hole under the step. It's a rather fragile-looking setup but I can understand the basic concept.
OK, have found it... In the manual it says
"If you want to speed up the filling process, also open the gate valve on the transom by pulling upward on the valve handle. This handle is located just to the right of the engine (as you face aft). Remember to close it after filling the tank."
Ooer. So i do indeed have two valves, and it seems later models they did away with the center valve and just use the transom valve? And moved the vent plug?
Just an RV black or gray water valve
That sounds impossible to find in Borneo... Aha, I find this... does this look like it will fit? I have no idea how it's physically attached on the boat?
https://shopee.com.my/Kokoa-75mm-RV-Dum ... 4648143835
Let's check BWY...
Good job I checked!
http://shop.bwyachts.com/product-p/h209-1v0.htm
"Fits all M19 and 26X thru mid 1997, Newer 26X and 26M use 3" valve. This valve comes with a plastic handle installed on it. Metal handles can be purchased separately with part H206-110."
So in later boats they removed the center valve and just made the rear valve a lot bigger.
Mmm.
Well i don't know if it really needs a new one but it looks pretty barnacle-eaten so I guess I'll order a new one.
Edit:
Just seen JimmyTs post about tomfoolery's post
Edit 2: $21 for the valve is cheap enough, but over $60 for postage is painful... I'll wait till it gets here, see if if really needs one.
Edit 3 - This is the same thing, right? A 1.5" RV dump valve:
I also see this one, with a funky cable..