Sedan Bridge Common Drain Plumbing

The gray water sump box is much further forward than the galley sink and all the food going through there... Not sure why Sea Ray thought that was the best plan.

I am doing this upgrade this winter. Have not figured out the best plan yet, either drilling new overboard drain out the Laundry Room Area as others have, also thought to increase the overboard outlet size for the Washer and add a Y-Fitting. My preference was also to tie into the main drain line.

I assumed I would tie into the exit pipe from the sump box, somewhere in the laundry area. Just haven’t had a chance to trace it back yet.

Will share more once I do.
I just can't come to terms with cutting a hole in the side of the boat and why exploring the use of the common drain. This first picture is the starboard side common drain where it turns down into the lazzerett behind the ice maker in the cockpit. From here it runs forward (left) inside that sealed gunnel area; I just don't know how far forward and what it will take to get to it. The braided hose and white hose are to the bridge AC unit; the other white cuffed line, now removed, was to the old ice maker. The second picture is behind the Starboard sofa/bed; the grey line is the central vacuum line to the aft connection point. The access cover on the floor is to the starboard fuel sender and the access plate on the wall is to that area inside the sealed gunnel where the drain line should be if it runs that far forward. Just to the left of that access plate is the galley cabinet with the sink. FYI the same removable panel on the port side gains access to the port common drain for all the drain lines running down from the bridge sink and cooler. Looks like I'm the trail blazer here.
starboard common drain.JPG

IMG_2636.JPG
 
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I just can't come to terms with cutting a hole in the side of the boat and why exploring the use of the common drain. This first picture is the starboard side common drain where it turns down into the lazzerett behind the ice maker in the cockpit. From here it runs forward (left) inside that sealed gunnel area; I just don't know how far forward and what it will take to get to it. The braided hose and small white hose are to the bridge AC unit; the other white cuffed line, now removed, was to the old ice maker. The second picture is behind the Starboard sofa/bed; the grey line is the central vacuum line to the aft connection point. The access cover on the floor is to the starboard fuel sender and the access plate on the wall is to that area inside the sealed gunnel where the drain line should be if it runs that far forward. Just to the left of that access plate is the galley cabinet with the sink. FYI the same removable panel on the port side gains access to the port common drain for all the drain lines running down from the bridge sink and cooler. Looks like I'm the trail blazer here.
View attachment 77247
View attachment 77248

I plan to tap into the main drain line up near the laundry if possible.
 
I plan to tap into the main drain line up near the laundry if possible.
If you are talking about the starboard common drain line it is above the laundry room. I really believe it stops right behind the sofa/bed where that access panel is but don't know for sure.
 
A sketch of where I believe that common drain is located (the red line). The only possible reason (I think) SR didn't tie into it for the galley sink is to prevent engine exhaust gases from migrating back through as it does exit right next to the exhaust port. If a P-trap is installed at the sink then that issue would be resolved.
stbd common drain 1.jpg
 
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I like the idea of it going into the common drain but My concern is the long run and turns that the common drain takes. As much as we try to be good about putting too much down the kitchen sink we do live on the boat a lot in the summer and it is inevitably that stuff goes down the drain with kids and guests using it. I am worried about sludge build up over time. I like the short run overboard that a thru Hull would provide. How close to the water line would be ok for the they hull. I see them very close to the water line on many boats and this drain goes upward immediately so even when listing into a wave it seems it would take a lot to run in the line. I will install a Groco through hull that has the 90deg bend built in so before the water gets to any connections it would be about 8-10” above the water line.
 
As already stated here, the 550/58 galley sink drains into the common drain run. Also worth noting that it has a p-trap.
 
A sketch of where I believe that common drain is located (the red line). The only possible reason (I think) SR didn't tie into it for the galley sink is to prevent engine exhaust gases from migrating back through as it does exit right next to the exhaust port. If a P-trap is installed at the sink then that issue would be resolved.
View attachment 77250
Tom,
My dockmate had an '05 500DB - I believe the same as yours with a different badge. As I recall, the laundry is below the galley. Looking at your diagram, it looks like you would have plenty of drop to the common drain manifold from the galley sink...
 
If you are talking about the starboard common drain line it is above the laundry room. I really believe it stops right behind the sofa/bed where that access panel is but don't know for sure.

We need to follow the discharge pump from the gray water sump box under the floor. I believe that discharge goes back towards the bilge area in the Laundry.

Still need to confirm this...
 
So I did some investigation today and found:
  • The sink drain (looks to be 1 1/2 inch) exits through the galley cabinet starboard side and routes down behind the freezer to under the galley then behind the washer/dryer and over to the tunnel and on to the sump box; about 30 feet in length.
  • It appears the starboard 2 1/2 inch common drain routes forward and ends also behind the freezer.
  • It appears also the forward bilge pump and sump discharges into the starboard common drain behind the freezer.
  • There is a P-trap on the galley sink.
It would seem obviously simply to cut off the sink drain line, modify the common drain to add a vertical tap, then tie in the sink drain as they all seem to be behind the freezer. I'll pull the freezer out and look. First pic is under the galley against the starboard hull side. The second picture is what looks to be the starboard main drain exiting that sealed gunnel and going into the galley cabinet side.
Stbd drain under galley.jpg
Stbd Drain Mid.jpg
 
And another picture in that tight space showing the hot and cold water lines going to the galley sink and where that "45" is printed is the back of the cabinet aft of the galley sink. The galley sink drain line is just about eight inches further forward of the hot and cold water lines but can't be seen in this pic. Showing what I think is the common drain below painted black.
IMG_4304.jpg
 
So I did some investigation today and found:
  • It would seem obviously simply to cut off the sink drain line, modify the common drain to add a vertical tap, then tie in the sink drain as they all seem to be behind the freezer. I'll pull the freezer out and look. First pic is under the galley against the starboard hull side. The second picture is what looks to be the starboard main drain exiting that sealed gunnel and going into the galley cabinet side.

I agree with that idea but maybe a Y valve on the sink drain that would allow you to easily switch a valve back to the Gray Water Sump if it is causing some issues.

Where were you taking these pictures from?
 
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If you pull the back cushions off the sofa/bed on the starboard side and look in there, this on the far left side (next to that first cabinet before the sink).
I like the Y-valve idea.
 
Looking forward to pulling the freezer out to gain access.

thanks for the trail blazing...
 
I pulled the freezer out and the starboard common drain is right on the hull side of the sink cabinet. The two white corrugated hoses connected on top are from the forward bilge pump and sump. The white line coming into the end is from the forward AC unit and dumps water into the drain when any one of the three units are cooling or heating. The gray line going through the hull is from the central vac and silver duct is the vent from the washer/dryer. The white line in the far right bottom of the picture is the sink drain. Right there.... The common drain is about 8 inches below the sink drain line coming through the cabinet. I'm going to cut in a Tee and tie in a new hose to the sink and cap the existing line for now to see just how well it's going to work.... Getting back in there to cut in a tee is another story.
IMG_4311.jpg
 
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Never clean and easy... Might try to convert the end cap drain into accepting both the Kitchen drain and the A/C Drain with some sort of Y fitting with reducers as needed.
 
I pulled the freezer out and the starboard common drain is right on the hull side of the sink cabinet. The two white corrugated hoses connected on top are from the forward bilge pump and sump. The white line coming into the end is from the forward AC unit and dumps water into the drain when any one of the three units are cooling or heating. The gray line going through the hull is from the central vac and silver duct is the vent from the washer/dryer. The white line in the far right bottom of the picture is the sink drain. Right there.... The common drain is about 8 inches below the sink drain line coming through the cabinet. I'm going to cut in a Tee and tie in a new hose to the sink and cap the existing line for now to see just how well it's going to work.... Getting back in there to cut in a tee is another story.
View attachment 77545
Tom, I'm amazed they didn't do that from the factory; sure looks like gravity could easily do its job...
 

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