Head plumbing according to regulations

[Petar]

Where can i find simple explanation on how should a sailboat head plumbing be done to comply with regulations?

On my previous boat I had a "Y" valve with an option to pump into holding tank or overboard depending on where I am with the boat. Here in PNW emptying the holding tank at numerous pumpout stations was pretty easy and effective.

On my current boat though there is no "Y" valve but the head pumps out into holding tank which can either be emptied overboard with a Sealand T12 marcerator pump or at pumpout stations. I would like to install the "Y" valve option to this arrangement as well. Am I allowed?

[Minnewaska]

If you are asking whether you can install a Y-valve at the head to avoid the holding tank altogether, that would be acceptable for regulation as long as you secure the overboard discharge just like any other, when required.

However, I think skipping the holding tank can be a bad idea for any length of time. Keeping aerobic bacteria alive in the holding tank is the only way to keep it from stinking up the joint. If you let it go dormant, I would think you would need to clean it out thoroughly.

[JimsCAL]

Your current arrangement gives you all the flexibility you need. With a Y-valve before the tank, there is much greater possibility of an accidental discharge in restricted waters. I would leave it as is.

[peikenberry]

Actually both are right. But I would leave it alone. It works, and minimizes the chamces of an accidental spill.

[jackdale]

I sail in the PNW - mainly BC

You present system is all you need. Simpler is better.

You will not have think about about where your Y valve is positioned.

When you come up north just hit the switch, unless you are in a no discharged area.

Protecting B.C. Waters From Boat Sewage Discharge

[mitiempo]

I agree, keep it as it is. In addition an additional Y valve will add 3 more connections that could leak at one point in the future. Simpler is always better.

[RocketScience]

Originally Posted by Petar

...I would like to install the "Y" valve option to this arrangement as well. Am I allowed?

Yes.

An excerpt from the US Coastguard regs on this issue:

"Y valve. Type III MSDs having a through hull Y valve must only be opened when the vessel is offshore, beyond the limit of U.S. territorial waters. At all other times, the valve must be positively secured in a way that presents a physical barrier to valve use and prevents all discharges. Adequate means include the use of padlock, non-releasable wire-tie, or removal of the valve handle. For more information see 33 CFR 159.7."

Here's the link:
US Coastguard Marine Sanitation Device