Seacocks & Thru hulls

[Dixie Life]

While doing some remodeling I came across a couple thru hull fittings; for a kitchen sink drain & bilge pump. Each has a seacock. These are several inches above the water line. My question is are there normally seacocks on above water thru hulls use for drains? If their not necessary I'd like to remove them. The handles are in the way of my remodeling and presenting a problem. However, if this is what's called for I'll work around them.

Thanks

 

[ranger58sb]

None of our above-the-water-line drain/discharge thru-hulls have valves. Nor did any on either of the previous two boats...

The only discharge outlet that has its own valve on ours is the holding tank macerator pump...

-Chris

 

[rwidman]

While doing some remodeling I came across a couple thru hull fittings; for a kitchen sink drain & bilge pump. Each has a seacock. These are several inches above the water line. My question is are there normally seacocks on above water thru hulls use for drains? If their not necessary I'd like to remove them. The handles are in the way of my remodeling and presenting a problem. However, if this is what's called for I'll work around them.

Thanks

A seacock on a bilge pump outlet? That's insane.

A seacock on a sink drain? I can see it on a sailboat that might heel but not on a trawler. Seacocks are only needed on thru hulls that are or might be below the water line.

Unless I'm missing something, I would say you can remove them.

 

[DavidM]

Macerator pump thru hulls are often way below the water line for obvious reasons ;-).

I think it is good practice to have seacocks on thru hulls within a few inches of the water line. Heeling and sea state could cause water to come in if there is a breach in the plumbing inside. You would have no way to shut it off with no seacock.

I can't swear to all of them but several of my recent boats had such seacocks including bilge pump discharge.

"A seacock on a bilge pump outlet? That's insane."

Well, maybe and maybe not. When I took delivery of my then new Mainship 34T in 2006 I noticed that the main bilge pump discharge had a seacock installed and it was located 6" or more above the waterline and it was closed. I opened it and put a wire tie on the handle. That was a huge manufacturing/commissioning mistake.

But I also note that the main bilge pump discharge on my current boat exits just an inch or two above the waterline and does have a seacock which was open when I bought the boat and still is. I am glad it is there.

I do know that A/C raw water discharge on some of my boats was 6" above the water line and had no seacock. I think a less than 6" rule of thumb for seacocks is appropriate.

David

 

[jleonard]

My old Albin has seacocks at every drain as you describe.
I have never shut them. In my opinion they don't need to be there.

 

[kchace]

My boat has a seacock on every hull penetration below or above the waterline and I'm glad it does. In my opinion, unless an opening is far above the waterline even moderate seas could push water in. Seacocks don't turn themselves. I'd rather have a seacock and leave it open than to not have one and want a way to close it.

Ken

 

[Northern Spy]

Don't have my standards with me this shift, but if I recall correctly, if the thru hull is under water at a seven degree list is the determinant for heeled waterline on a power boat.

I have ball valves on all above water thru hulls (2 sinks) except for my bilge pump overboards; on those I have high loops.

 

[psneeld]

I believe Northern Spy is on track and that sea cocks are "suggested" for any through hull within so many inches of the waterline.

Hopefully someone can post the ABYC guidelines.

Like J Leonards Albin...mine also has all the factory through hulls at the boot stripe, including bilge pumps for the exact same simplistic reason, with sea cocks. While not a huge issue with coastal cruisers, Bluewater boats are sure to have them.

If you break a hose or it slips off, etc.....even bilge pumps with high loops but discharging at or near the waterline , securing the opening to the sea is simple damage control.....you can wire tie them open or closed till needed, but way easier than trying to find the correct bung unless the bung is tied to it, then there is still the struggle to stem the flow.

A friend's 33 Egg Harbor sportfish broke a thru hull without a seacock on it and he could hardly make way without water pouring in. Things jammed in eventually work loose and for the want of a seacock......

 

[rwidman]

I used a highly recommended and well respected surveyor when I bought my boat and he made no mention of any lack of seacocks on my above the waterline thru hulls.


Keep in mind that if you do have seacocks and expect them to work when you think you need them, you really should close and open them several times every month or so. A seacock that's been left in one position for a long time may freeze in that position and be useless when the time comes to use it.

 

[psneeld]

Basic maintenance is required for all systems...probably the ones that can keep your vessel afloat are somewhat important in many boaters minds....

Seacocks: Part I | | PassageMaker

In order to comply with the above-recommended guidelines, it is important to clearly understand the phrase “maximum heeled waterline.” On a sailing vessel, this demarcation is defined as the level of the water on the hull when the hull is inclined to the level of the sheer amidships.*Any*hull penetrations that are wet under these circumstances are considered to be below the maximum heeled waterline. For power vessels, the guideline is somewhat more lenient, encompassing hull penetrations that would be submerged if the vessel were to heel up to 7 degrees. My personal comfort level typically dictates that seacocks be installed on penetrations that are less than 12 inches above the static waterline on power vessels.


I know people will argue heel versus roll...have at it...spend some time at sea taking on water from rolling and your definition may expand....

 

[rwidman]

I would think that one would want any seacock on a bilge pump outlet to be open when underway. And when not underway. Actually, any time the boat is in the water or out of the water but not in a building (because of rain).

 

[Bacchus]

Again - I agree w/ djmarchand... My Mainship has valves on many of the above waterline through hulls. I don't believe any include a vented loop - but not positive / haven't seen any...see ABYC below re: bilge pumps / systems

ABYC Excerpt from H.22

22.8.5
Pump discharge systems shall be as nonrestrictive as practicable.
NOTE:
As installed, pump discharge capacity may be educed by such factors as
a. length of discharge piping, and/or
b. number and radius of bends, and/or
c. roughness of the interior surfaces of piping and fittings, and/or
d. reduction in cross-sectional area of discharge system components such as check
valves and thru-hulls.
22.8.6
The discharge location shall be above the maximum heeled waterline, or
22.8.7
the discharge may be located below the maximum heeled waterline if the discharge line is provided with both of the following:
22.8.7.1
a seacock installed in accordance with the requirements of ABYC H-27, Seacocks, Thru-Hull
Connections, and Drain Plugs, and
22.8.7.2
a vented loop or other means to prevent siphoning into the boat. A check valve shall not be used for this purpose....

 

[kchace]

I would think that one would want any seacock on a bilge pump outlet to be open when underway. And when not underway. Actually, any time the boat is in the water or out of the water but not in a building (because of rain).

I completely agree and my bilge pump outlets are never closed, but I do like it that I have proper seacocks that allow me to close any of these thru hulls if I want/need to.