New Boat Sink Scupper Connections?

[David M]

A couple Sundays ago, I was asked if I could skipper a one year old 49 foot Hunter for a local companies employee party. The boat was being chartered out of a sailing club in the Bay Area.

After about two hours into the charter, the galley sink and the after head sink started backing up. I put someone else on the helm and went below to have a look. Raw sewage (at least what looked like raw sewage and smelled like it) was in the bottom of the galley sink and the after head sink. It did not smell like old salt water that had been sitting stagnant in a hose. It had a yellow color as well.

I did not have the time to trace the problem since I had to get back up topside to run the boat.

My question is, is the gray water on new boats sent to the holding tank or is it plumbed directly overboard? It there an ABYC rule for this? To me it seems gray water should never be plumbed to the sanitation tank for this exact reason.

The sailing club claims that the gray water is sent directly overboard, but I could swear that it was raw sewage. Needless to say, although it ended up being a nice day cruise overall, but it was not as pleasant as it could have been.

They also claimed to have filled up both water tanks, but the heads, which used fresh water from these tanks, had no water coming from them after a while. It was only after we got back to the dock and filled the water tanks that the heads had fresh water flowing in to them. Could this fact be related to the problem of having raw sewage in the sink scuppers?

The club is in denial that raw sewage could have been coming up the drains, they also claim the water tanks were full when the boat left the dock. We did a checkout the Saturday before the cruise, but their tank level gauges were of question. The person who checked us out said so himself. My guess is that the fresh water tanks were near empty and the sanitation tank was near full when we left the dock.

[Vasco]

AFAIK gray water goes overboard in North America. Can't see how sewage can get into the sink drains unless you were sailing in sewage and heeled over badly on the sink side. One outside guess might be that the charter company was peeing in the sinks and the lines were plugged a bit. This peeing in the sink is done more than you think by folks that don't want to fill up the holding tank, quite often by shore staff. Sounds like the charter company didn't check the boat out properly.

[speciald@ocens.]

Dead marine life trapped in the drain circuit can smell like sewage. Were you healed over when the sinks backed up? All my sink drains have one-way valves to keep that from happening - too expensive to put on a Hunter?

[David M]

I know the smell of dead phytoplankton and zooplankton that has been sitting in hoses for weeks. It was a different smell. I think Vasco may have nailed it, someone had been peeing in the sinks previous to the charter.

This Hunter had a lot of nice goodies...not the best sailing boat though and questionable fit and finish. Why they did not put check valves on the sink drains I have no idea.

[GordMay]

Might you have experienced a sewage backflow into the potable water tank?

ABYC H-23 Potable Water Systems (23.5.1) requires that the potable water system is TOTALLY separated from contact with water used for ANY other purpose.

If fresh (potable) water is used to flush the sewage system, an appropriate backflow prevention device must be provided. An air-beak is thre most positive device.

ABYC has/is publishing a new advisory on Sewage Systems (TH-29), which may provide additional detail.

[S&S]

Some boats travelling in "Zero Discharge Areas" have the sink Y-'d to the holding tank. Maybe this was a similar set-up?

Note- this is not "good practice". They really should have a seperate tank.

[Solitude]

If grey water was connected to the holding tank and they accidentaly filled the holding tank instead of the water tank, maybe it all backed up?

This would explain that they claimed to fill the water, the fresh water ran out quickly,

I don't know how often the heads were used but...

[GordMay]

Originally Posted by GordMay

... If fresh (potable) water is used to flush the sewage system, an appropriate backflow prevention device must be provided. An air-beak is the most positive device...

I should have said an "INDIRECT"* connection is the most positive device.

* Such as a hand-held shower faucet, not long enough to submerge below the toilet bowl rim.