So I was reading a thread on this topic in the forum from 14 years ago.  Since I am the head cook and bottle washer (and Chief Mechanical Engineer) on our 2003 MKII, I want to try and solve the slow draining problem.  My older Bro is the Captian and electronics Chief. The Cat 36 is currently on the hard so yesterday I ran a small diameter snake up the through hull and there was absolutely no obstruction in that part of the drain hose.  Once I got on to the boat I removed the galley sink drawer and through hull access panel to get a clear view of the plumbing.  I've included a picture of what I saw.

I'm thinking I should rotate the drain line T-joint 90 degrees so it faces downward.  Simple physics would make gravity promote faster draining.  Is there a reason this was setup this way? 

I saw someone in a related post said they extended the drain lines from each sink and lowered the T-joint in the process and that seemed to help.  So how about extending each sink drain hose and join it to a Y-joint further down for a more direct and gravity driven water flow.

I'd love to hear if others have had this issue and if it bothered anyone enough to fix it.