sink drains

yorklyn · Post by **yorklyn** » Mon Feb 13, 2012 5:26 pm

A siphon break is a must on any hoses that travel below the water line inside the boat. I use one whenever possiable on my thru hulls for cheap insurance. If a bilge pump dies during a storm and the boat takes on alittle weight, it doesn't take much to have an "above waterline thru hull" to turn into a funnel.
Helped a buddy who owns a sea tow business salvage a boat in the slip that had some storm surge waves break over the transom, bilge pump kicked on but eventually killed the battery (no shore power) weight of the water put the low bilge pump thru hull at the mercy of the waves which turned it into a funnel .
I now buy my hoses a foot or two longer and make a high loop as a siphon break.

Paul · Post by **Paul** » Mon Feb 13, 2012 6:12 pm

yorklyn wrote: I now buy my hoses a foot or two longer and make a high loop as a siphon break.

Be careful Todd, a high loop in a in a hose does not make a siphon break. To create a siphon break, you have to install fitting with a "duckbill" valve at the top of the loop. These are great for hoses that run down in the hull below the water line such as a bilge pump hose. I use them in my aft bilge pump hoses.

Now the hoses that are in question here are the hoses that the F-26 has that runs from the galley sink on a down slope to a bulkhead fitting at the boot stripe just above the water line. Creating a siphon here is not possible.

jefflaw35 · Post by **jefflaw35** » Mon Feb 13, 2012 6:28 pm

Paul wrote:
yorklyn wrote: I now buy my hoses a foot or two longer and make a high loop as a siphon break.
Be careful Todd, a high loop in a in a hose does not make a siphon break. To create a siphon break, you have to install fitting with a "duckbill" valve at the top of the loop. These are great for hoses that run down in the hull below the water line such as a bilge pump hose. I use them in my aft bilge pump hoses.

Now the hoses that are in question here are the hoses that the F-26 has that runs from the galley sink on a down slope to a bulkhead fitting at the boot stripe just above the water line. Creating a siphon here is not possible.

Paul? the Duckbill valve? is that similiar to the one-way direction valve you would see on a well pump system at home? just asking, guess i could google it

jefflaw35 · Post by **jefflaw35** » Mon Feb 13, 2012 6:30 pm

didnt really think i would get this kind of responce to a sink drain post, man this gonna be a long restore project, i love it!

captainmaniac · Post by **captainmaniac** » Mon Feb 13, 2012 6:35 pm

At one point in time I had issues with water on the floor of the shower drain in my F32 after running in certain sea conditions.

Occurred after I 'fixed' a plumbing problem - the hose from the drain had an inline filter between the drain and the overboard pump, and the hose had come off the filter. After the carpet got wet I realized why the hose was disconnected - a prev owner had apparently decided it was better to just let the water flow into the bilge than the shower pan.

I added a checkvalve between the overboard pump and hull fitting to make sure I didn't get reverse flow anymore.

jefflaw35 · Post by **jefflaw35** » Mon Feb 13, 2012 6:41 pm

captainmaniac wrote:At one point in time I had issues with water on the floor of the shower drain in my F32 after running in certain sea conditions.

Occurred after I 'fixed' a plumbing problem - the hose from the drain had an inline filter between the drain and the overboard pump, and the hose had come off the filter. After the carpet got wet I realized why the hose was disconnected - a prev owner had apparently decided it was better to just let the water flow into the bilge than the shower pan.

I added a checkvalve between the overboard pump and hull fitting to make sure I didn't get reverse flow anymore.

"check Valve" thats the word i was thinking of. it would make sence to use these to me. bt at the same time. its maintence forever. salt, mold, lots of stuff i would think can make it malfunction. but at the same time if you ever did have an issue it would help. but if its not your lowest laying area the gravity should never pull water up.

captainmaniac · Post by **captainmaniac** » Mon Feb 13, 2012 6:55 pm

jefflaw35 wrote:but if its not your lowest laying area the gravity should never pull water up.

When you are under way it can be more of a pressure situation - pushing through waves, water running past the hull, can create pressures that will push the water up hill...

jefflaw35 · Post by **jefflaw35** » Mon Feb 13, 2012 7:15 pm

captainmaniac wrote:
jefflaw35 wrote:but if its not your lowest laying area the gravity should never pull water up.
When you are under way it can be more of a pressure situation - pushing through waves, water running past the hull, can create pressures that will push the water up hill...

sounds about right, I guess poop can run up hill lol, was alway told 3 things to know about plumbing was hot to the right, cold to the left and poop don't run up hill lol. I can see, sea water doing this on a short drain under the right situation

alexander38 · Post by **alexander38** » Mon Feb 13, 2012 7:28 pm

and don't run gray water to a black water tank...the smell will be notice of why not...when the eco nazi's put a stop to gray water dumpin' new tanks will be needed...

yorklyn · Post by **yorklyn** » Mon Feb 13, 2012 8:46 pm

Paul, Your correct. I'm using the term "siphon break" incorrectly. A true siphon break resembles this
http://www.mabrumarine.com/admin/upload ... kohler.jpg
I have used a "elevated loop" on items such as my bilge pumps, basically keeping the hose elevated a foot or two above the thru hull so waves during a bad storm can't "pour directly " into the bilge without going up through the elevated loop first. not really a siphon break without a vented loop to break the siphon. Thanks

Commissionpoint · Post by **Commissionpoint** » Mon Feb 13, 2012 9:44 pm

alexander38 wrote:and don't run gray water to a black water tank...the smell will be notice of why not...when the eco nazi's put a stop to gray water dumpin' new tanks will be needed...

No gray water dumping here. Been that way as long as I can remember. Most people have more than one tank. We get inspected to make sure all non bilge water thru hulls are sealed. Cockpit drains are ok too. Anything with a sink, shower. or head has to go in a tank. Sink sumps can be helpful when you convert to gray water holding, it really depends on your application. I've had cuddys where we just calked the sink thru hull from the outside and put the hose in a jerry can under the sink. You just emptied it ashore after the weekend. Those were small pump style cold only sinks you see sometimes on boats in the 20-25 foot range.

Its amazing the eco regs here, but the water quality is incredible.

http://www.lgpc.state.ny.us/Regs.html

Espescially this.

http://www.lgpc.state.ny.us/Special_Nav ... Rules.html

Talk about Facists.....

Muskokan345 · Post by **Muskokan345** » Tue Feb 14, 2012 2:56 pm

Not to put too fine a point on it but, the question was specific to an F25, thats why I chimed in, I have an F26 and offered up the "loop" input, I realize that things can and are different on "big" boats, but that wsnt the question, however, tons of great input from all. BTW, as they say around here, "This is Muskoka, we make $hit run uphill!"

jefflaw35 · Post by **jefflaw35** » Tue Feb 14, 2012 8:10 pm

acually the question was specific to a legal term that included all boats, but i agree, there was alot of good info here. question was " is it still legal to dump sink water" had nothing to do with the F-25 or myself. it was a question about dumping recycled water..

Paul · Post by **Paul** » Tue Feb 14, 2012 8:17 pm

Muskokan345 wrote: "This is Muskoka, we make $hit run uphill!"

Nice area to be boating in. Spent a few summers boating not to far from there. Launched the boat at Honey Harbour and wend cruising around the islands for a week at a time. Walked around on allot of rocky islands but stayed off of the hills.

Paul · Post by **Paul** » Tue Feb 14, 2012 8:50 pm

Todd,

The bilge pumps are exactly where I learned about the siphon breakers. Like you, I ran my hoses up in a high loop to keep water from washing back in thru the bilge hose. This worked great until one day when I had several people in the cockpit and I decided to turn on the bilge pump. It pumped the little bit of water that was in the bilge out but since the drain hole was submerged at the time from the load in the cockpit, when I shut the pump off it created a siphon and the water started flowing into the bilge. I noticed it since the auto pump indicator kept coming on. Moved a couple people forward until the drain hole fitting broke the surface of the water and the problem want away.

To make sure that this didn't happen again I installed siphon breakers on the bilge hoses at the top of the loop. Below is a picture of a siphon breaker like the one in your link. The part that I'm pointing to houses a rubber duckbill valve.

Below is a picture showing the valve and the cap that holds it in place.

The duckbill valve is called that because its shaped like that. It has a slit in the end of it which allows air to be drawn in which allows the water to drain out each side of the fitting by creating a pocket of air in the fitting. This is how it breaks the siphon. When the pump is turned on, the valve closes from the pressure and out goes the water. Below is a picture of the duckbill valve.

As far as the sink drains that started this post are concerned, if the sink is above the waterline and has a free drain (no pump) straight out no a down slope (with or without residential trap shape) it will not create a siphon.

Hope this clears things up a bit.