Venting sink drain

[Billberner]

I have a center cockpit boat with a double pan galley sink located on the boats centerline. The 2 drains are connected with a horizontal pipe that connects to a 1 1/2” hose, vented loop, and exits the boat below the waterline.
The sink drains VERY slowly and water backs up into the second pan of the sink. Doesn’t matter which pan I’ve just used.
I’m considering teeing in a second hose near the vented loop and running it well above the waterline into a galley locker, my hope is that by venting the drain, the sink will empty faster.
Thoughts?
Thanks

Bill Berner
2006 Passport 470
Galesville, MD