Shutoff valves. open or closed?

Scott T-Bird · Nov 5, 2015

capta said:
If you start your diesel with the seacock closed, you will have destroyed the impeller by the time you can shut it down after finding no exhaust water through visual inspection, 99 times out of a hundred. It may not show for a while, but the damage is done and impellers do not self repair. So, if one does make this mistake, change the impeller on principle, just to be safe because it will fail soon afterwards, if not immediately.
Low water flow is not at all the same as no water flow, sucking against a closed valve.

Maybe for larger impellers. I've not found that to be the case on the smaller ones that I have and I have done it a few times with the current impeller. When I've done that, though, I hear the odd sound from the exhaust even before looking for the discharge, so I tend to shut down pretty fast, like almost immediately after the engine catches.

I've never experienced an impeller failure to the extent that the vanes are even damaged. I've replaced numerous failed impellers where I can't tell the difference between the failed impeller and the new impeller. I always have spares on board and tools, so impeller failure just doesn't give me much concern.
But my experiences may not be the same as others ...

centerline · Nov 5, 2015

what I learned from the previous owner of our boat, who claimed to be a delivery captain and "marine maintenance expert" as he so boldly claimed to be, it that its a good habit to keep the valves closed... not because he told me so, but because he was one who didnt believe it was necessary to do... except if you are going to be away from the boat for long periods of time.
In a round about way, that is how we came to own the boat..
the last winter he owned it, the seawater intake filter froze and broke... it was found out in time when a dock neighbor reported that it was rather low in the water....
it turned out to be extremely expensive for him to get emergency crews to the boat in time to prevent its sinking at the dock
it suffered no lasting damage due to it only getting about 8" deep above the cabin sole and the the quality of the wood that was used inside the boat, but it still cost him several thousand dollars for the cleanup and repair, just so he could sell it to pay for the stupidity.... or "bad luck", whichever you want to call it.

everyone has their own opinions as to when and why, and will adopt their own tactics, but I think its wise to keep the valves closed when you are going to be gone from the boat over an hour, or when sailing in extreme weather conditions...and its just as important to absolutely know, NOT just assume, that the valves, filters and lines are all in good order.

and although I dont keep my Ignition key hanging ON the seawater intake valve, but I do keep it on a secure hook inside the compartment where the valve is located. (out of sight of any theives in the event of a break-in)

EDIT... and Yes, my pump suffered impeller damage within about 30 seconds after forgetting to open the valve... after starting, i looked over the rear and could see no water or dribbles and immediately realized what I didnt do... shut down the engine as the key was right there, and then opened the valve. then restarted.... there was never any flow afterward.
it ate the impeller... i had assumed it was due to being an old impeller that was probably old and dry.
but it doesnt matter, because I vowed that this could never happen again, especially if i were in a rough seaway and needed the engine quickly for some reason... although the valve and keys would probably be in their respective positions to run the engine, to minimize the risk at all times, I moved the keys in with the valve.

Gunni · Nov 5, 2015

Plenty of boats flood with closed through-hulls AND improper winterization.

Maine Sail · Nov 5, 2015

Justin_NSA said:
I hear what you guys are saying. NONE (5) of my valves are mounted directly on the thru hulls. The boat is a '91. Is it original? Who knows. I find it hard to believe someone changed all of them. Is it acceptable? All I know is they work and it has been surveyed and Coast Guard inspected. Even as anal as I am, I probably won't change them unless they leak. Curiousity will drive me to see if the thru hulls are threaded and will accept a standard seacock.
This does explain to polarity of opinions on closing them to prevent leaks though. Great discussion guys.

I have never seen Hunter install a hose between the seacock and thru-hull fitting. Seems like the PO did you no favors. The design & intent of the seacock is to be BEFORE any hose.

#1 I am simply amazed your vessel passed a survey, it SHOULD NOT HAVE. The only explanation for why it did is because your surveyor was simply not doing his or her job. A seacock is hard fixed to the hull with no hose in-between. Bad surveyor, bad, bad, bad...

#2 Any vessel built with seacocks that are not "readily accessible" is simply NOT BUILT to acceptable marine standards. We can close all of ours below waterline seacocks, on a 36 footer, in 45 seconds or less. This is how seacocks should be installed. Readily accessible.

ABYC:

"27.6.1 A seacock shall be securely mounted so that the assembly will withstand a 500 pound (227 Kg) static force applied for 30 seconds to the inboard end of the assembly, without the assembly failing to stop the ingress of water.

27.6.1.1 The installation shall prevent any movement of the assembly.

27.6.1.2 Thru-hull fittings and seacocks shall be connected directly.

27.6.3 Seacocks shall be readily accessible as installed, and oriented that their handles are easy to operate."

One of the worst places to leave a seacock open on is an engine or an air conditioner.. There are FAR TOO MANY seal failure and corrosion points on an engine or AC system to make it wise to leave a seacock open on an "unattended" vessel. Course if you like going to Vegas, you can get lucky & win...

Boat US:
"In 50% of dockside sinkings, water found its way into the bilge through leaks at underwater fittings. The majority of the leaks are at stuffing boxes, followed by outdrive or shift bellows, failed hoses or hose clamps, sea strainers, and drain plugs."

Failed hoses, hose clamps and sea strainers can 100% be prevented from sinking your boat if you close the seacocks.

When the overwhelming recommendation in the industry, including actual insurers like Boat US, suggesting to close seacocks on unattended vessels, unless they are cockpit scuppers, and you choose not to, how will your insurer handle a claim?

How will they handle a claim when a hose or clamp fails, or a seal on a raw water pump (wear & tear?) now stack this on top of an improper seacock installation & you failed to make any effort (neglect?) to limit your boat from sinking by closing them?

Here is a pretty typical Policy:

"D. EXCLUSIONS

In addition to the SECTION TWO: GENERAL
POLICY EXCLUSIONS, we do not cover loss or
damage caused by or resulting from:

1. Wear and tear; neglect;

2. Gradual deterioration; deterioration caused by
weathering, insects, or marine life;

3. Insects, animals, vermin, marine life, mold,
mildew, or fungus;

4. Marring, scratching, weathering, fading, chipping
or denting;

5. Inherent vice, wet or dry rot, rust or corrosion;

6. Osmosis, blistering, delamination, chemical
decomposition or galvanic action;

7. Latent defect. However, any resulting direct
physical loss or damage to your boat resulting
from the latent defect will be covered;

8. Defects in manufacture, including defects in
construction, workmanship and design other
than latent defects as defined in the policy;

9. The insured's failure to properly winterize the
boat in accordance with the manufacturer's
specifications or customs of the area;

10. Theft or unexplained disappearance of auxiliary
equipment unless:

(a) your boat is stolen
at the same time; or
(b) there is evidence that the property was forcibly removed;

11. Decrease in value, loss of use, or lost profits;

12. Previously unrepaired damage that occurred
either prior to the policy effective date as
shown in the declarations or where an insured
has previously received full or partial payment
from us; or

13. Mechanical breakdown."

Scott T-Bird · Nov 5, 2015

centerline said:
EDIT... and Yes, my pump suffered impeller damage within about 30 seconds after forgetting to open the valve... after starting, i looked over the rear and could see no water or dribbles and immediately realized what I didnt do... shut down the engine as the key was right there, and then opened the valve. then restarted.... there was never any flow afterward.
it ate the impeller... i had assumed it was due to being an old impeller that was probably old and dry.
but it doesnt matter, because I vowed that this could never happen again, especially if i were in a rough seaway and needed the engine quickly for some reason... although the valve and keys would probably be in their respective positions to run the engine, to minimize the risk at all times, I moved the keys in with the valve.

I know I'm being nit-picky

but 30 seconds IS definitely enough time to fry an impeller. I've never needed more than a second or two to have that oops moment when I realize the seacock is closed. That's barely enough time for the slug of water that was already in the pump and strainer to clear out the exhaust.

JamesG161 · Nov 5, 2015

Gunni said:
You hang a lock down/tag out on whatever disconnect you use to render the vessel's ignition inoperative. It goes to the the thru-hull valve when in operation, and back to the disconnect when you close the valve.

Very very good idea! I have 7 seacocks that will get seven numbered safety tags that all must be in their storage box before starting anything.

This is what I did for many years in the chemical industry to protect from loss of life/limb.
http://www.safetysign.com/custom-vinyl-tags
for my water proof tags to use soon.
Jim...

John T1594 · Nov 7, 2015

I have a 2000 Hunter 340 with six factory installed seacocks: three for water inlet (A/C; Head/ Engine) and three for drains (Galley sink/ Head sink/ Holding tank). All are mounted directly on the thru hulls except for the A/C, holding tank discharge and engine raw water intake and these have a short run of bronze pipe with a 90 degree elbow before the seacock. We use our boat every weekend during the summer and I keep all the seacocks open all season. The A/C intake has to stay open to keep water flowing to the compressor since it is set on "Humidity" mode and runs a few times each day. The engine raw water intake was placed by the factory under the middle of the large aft berth on our boat. To get to the seacock I have to strip the sheets and blankets off the bed and remove one mattress panel - so guess what - it stays open. I do check the strainer once a month and exercise the seacock but that's about it. All of my sink drains are kept open but my toilet inlet stays closed (we use fresh water only poured into the head) and the holding tank discharge seacock is closed and locked. I spray some white lubricant into each thru hull each spring and exercise the seacocks before launch. They are all getting a bit stiff but still able to be opened and closed. All attached hoses are double clamped and checked regularly for aging and cracking.

BigEasy · Nov 7, 2015

As others have stated, the engine raw water intake, head intake & Air Conditioner intake have to be located underwater.
If you don't close them, you introduce the risk of sinking. This summer, there was an older boat on my dock that sunk. The cause was a defective galley drain hose that burst; obviously the thru hull valve was left open. If you are concerned about running the engine with the raw water valve closed, just make a check list to run thru before start up! Also, as was previously mentioned, you should always check the exhaust thru hull for water discharge upon startup. Add that to the checklist also!

centerline · Nov 7, 2015

BigEasy said:
If you don't close them, you introduce the risk of sinking!

Yep. And however small the risk may be, as long as the valves are open, the risk is there, and can present a problem at any moment.
Depending on the owners maintence schedule, procedures and awareness levels, the risk factor may vary greatly from one person to another. and for someone to say there wont be a problem unless a connection is leaking, is the exact same as saying "theres not a problem, until there is a problem".. and the problem will be that the boat is sinking.
If your around at the time, then you can close the valve and stop it.... if not, then its going to be an expensive and messy clean up and repair.

The bottom line, when discussing "to close or not to close", is risk vs gain... what are you gaining by leaving the valves open, while at the same time taking the risk of losing everything?...

DougM · Nov 8, 2015

I certainly agree that seacocks should be closed when not on the boat. Manufacturers, however, don't exactly make that an easy task. On my boat, one has to take up the matress on the aft berth, then lift up the floor board and move it to even reach the engine water intake and the water pickup for the dripless seal. There doesn't seem to be an easier way,but its not worth the risk to leave them open.

JamesG161 · Dec 14, 2015

JamesG161 said:
I have 7 seacocks that will get seven numbered safety tags that all must be in their storage box before starting anything

I just finished implementing my seacock safety and reminder system I said I was going to do. My post#26 above.

Those are waterproof, no tear, tags in the link. My 9 seacocks are priority ordered based on safety/cost if not opened before leaving the berth ( both sides say same). Note the wire wrap seacock handle hangers, the indelible marker, my engine keys ( now stored on the seacock handle with the tag). The Admiral added 2 more good idea tags. Tag 3A that dangles in front of the genset start switch (no key) and the one under the key float, SEACOCKS CLOSED! tag that is in front of your face as you go below on the companion way.
We have a small tag sized box/lid with a map to the seacocks and index, for storage. All tags 1-5 must be returned to the box (after opening the valves) before you single up all lines. 6-9 are on a "as needed" basis.

When securing the boat, you take all tags from the box, close and tag each seacock, and double check that no tags are in the box. Go home and sleep peaceful about no unexpected flooding.
Jim...

PS: Admiral is very happy, but said my penmanship stunk! If anyone is interested I can show a homemade device to open and close those hard to reach seacocks with just a stick and a string.

arf145 · Dec 14, 2015

I'm a proponent of closing all seacocks, including ones that are above the water line. Boats have been sunk by failed hoses on above the water thruhulls. How? By having the waterline change through snow load or, say, a cockpit full of water because of a clogged scupper. You can't predict all the ways a bad thing can happen, but there's no changing the fact that those are holes in the hull.
Oh, and I've been keeping my engine key on the engine water seacock since I read about that years ago. I love the reinforcement of the association between the two, and it's really no inconvenience since I have to access the seacock anyway to get going or to close things up.

Gunni · Dec 14, 2015

Very thorough James. Good way to keep track of a lot of through-hulls and make it clear for the crew.

Pat · Dec 15, 2015

Justin, I keep ours closed when not on the boat. I open and close them periodically, whether I need to or not. Our monster 2 inch head pump out thruhull was closed several years ago during a sponsored NSA inspection by the Coast Guard.....I was the only one brave enough to get inspected. The rest of the owners went home to avoid inspection. I passed, but the CG tied off my thru hull so I could not pump directly into the water, which I did not do anyway....that since we have a free pump out dock at the YC....HOWEVER, the thru-hull is no longer usable as the handle was never turned on and off periodically as I should have done and is frozen in place. I'm not sure what would happen if I tried to force it open....I suppose there is still the opportunity for that line/ or thru-hull to leak..It is frozen in the off position and does not leak now. To make a very long story short...I always close all thru hulls when I leave the boat...and open them when I arrive at the boat. Patrick at Ninnescah

WayneH · Dec 15, 2015

Pat said:
.HOWEVER, the thru-hull is no longer usable as the handle was never turned on and off periodically as I should have done and is frozen in place. I'm not sure what would happen if I tried to force it open....I suppose there is still the opportunity for that line/ or thru-hull to leak..It is frozen in the off position and does not leak now. Patrick at Ninnescah

Patrick, I had a frozen OPEN head through hull on my boat when I bought it. I managed to get it to operate STIFFLY by tapping the valve stem with a hammer and moving the handle at the same time. After about ten minutes, I got the valve to move two handed. I kept tapping and moving the valve and got it to where the Admiral could close it by herself. So you can get it to operate after a while and very poorly.

Of course, the next time we hauled the boat, we had the valve replaced because the Admiral cussed everytime she had to operate the valve.