I have a MKII, aa 93.
I agree with the others, the corrugated hose coming in from the left in the pic is the manual drain pump. The pump is located in the port lazarette, under the lid, bolted to the cockpit side. There's a cutout on the cutout side giving you access to put a short pump handle into the pump.
The black & white hose coming in from the right in the pic is the shower drain.
The ice box drains to a foot pump located under the 3 drawer setup in the galley. From there it runs to a T at the galley sink drain thru hull. I've heard some owners have run the drain line directly to the bilge. Any liquids, like milk, can stink up the bilge real fast.
Plus cold air drops, hot air rises, so have line directly to the bilge allows precious cold air to run down to the bilge.
I removed all of that and put a rubber stopper in the drain. I have a small wet dry vac I use to take water out of the ice box and I don't use ice. I have a cold plate in there.