Wet exhaust seacock

Hi there,

We are looking at a 30' Sundowner Tug, but are new to this size of boat. The deceased previous owners son tells us that they have always left the wet exhaust seacock in the open position because since the seacock and the exhaust are almost at the same level, nothing would happen.

Every fibre of my being says this is wrong.

The seacock is located 1/2 way between the keel and the waterline beside the engine amidships, and the exhaust terminates just above the waterline aft. If any link in the chain between the two were to fail, wouldn't it at least flood the engine room...maybe even sink the boat?

Like I said...rookie here!

MurrayM said:

Hi there,

We are looking at a 30' Sundowner Tug, but are new to this size of boat. The deceased previous owners son tells us that they have always left the wet exhaust seacock in the open position because since the seacock and the exhaust are almost at the same level, nothing would happen.

Every fibre of my being says this is wrong.

The seacock is located 1/2 way between the keel and the waterline beside the engine amidships, and the exhaust terminates just above the waterline aft. If any link in the chain between the two were to fail, wouldn't it at least flood the engine room...maybe even sink the boat?

Like I said...rookie here!

Click to expand...

Always close your seacocks when leaving the boat.

I don't do it when I leave to go to shore and walk around, but I do close them when leaving the boat for an extended period of time.

Hi Kevin,

Thanks, that's what I thought as well. It's been like that for 3 years...

Murray

Murray

There are two schools of thought on closing engine RW seacocks. Some don't because the danger of forgetting to open and damaging the engine. I've heard of mechanics and boat watchers (another active thread on this Forum) not taking the time to insure seacock open and creating damage. I had a dock mate whose vessel was stolen for short joy ride, he was so happy he left his seacocks open. On a well found boat with good hoses and an attentive owner I can see both sides. I'm lucky in that all my active through hulls are in one location. Strangely, non engine through hulls are more "deadly" that engine through hulls from insurance claims - such as heads, watermakers, ACs, cold plate reefers, salt water wash down pumps, deck drains that go into bilge, leaving a high pressure water hose connected to the on-board water system etc.

And not to mention the sad cases where the through hull fitting fails when being closed, so lots to go wrong either way you choose.

You actually have a seacock on your exhaust?
If the line is not self draining, I would close it. otherwise it seems extra.

Maybe I'm misreading what the OP posted but it sounds to me as though the "seacock" is located away from the opening in the hull. In that case its just a valve. To function as a seacock it needs to be at the through-hull. During our haulout this spring I realized that our genset was plumbed directly to a through-hull with no seacock. The yard didn't seem to think it was any big deal but I put in a seacock anyway because it made me feel better. If the OP truly has a valve lying in the bilge halfway between the through hull and the engine that would really concern me - if anything happens to that line from the valve to the hull that could be a sinking event.

He's gotta be talking about the raw water intake side. I'm 'pretty familiar' with the Sundowner 30 and there's no shut-off on the exhaust side.

sunchaser said:

There are two schools of thought on closing engine RW seacocks. Some don't because the danger of forgetting to open and damaging the engine.

And not to mention the sad cases where the through hull fitting fails when being closed, so lots to go wrong either way you choose.

Click to expand...

When I close my seacocks I put a "seacocks closed" notice attached to the ignition keys and the generator control panel.

Another very good thing about closing your seacocks is that movement keeps them operational. Seacocks seem to get stiff to a point of being inoperable through disuse. Using them insures they are in good working order.

All of my seacocks are in the engine room within probably 10' of each other. I close them and open them all at the same time.

ksanders said:

Another very good thing about closing your seacocks is that movement keeps them operational. Seacocks seem to get stiff to a point of being inoperable through disuse. Using them insures they are in good working order.

Click to expand...

Excellent point Kevin and sadly overlooked by many if not most, judging purely from the boats for sale I've looked at. The most dangerous thing on a boat IMO is a valve that is not regularly exercised. Regular exercise also keeps the operator intimately aware of their location and function in an emergency.

Anode said:

He's gotta be talking about the raw water intake side. I'm 'pretty familiar' with the Sundowner 30 and there's no shut-off on the exhaust side.

Click to expand...

Could be - but intake or exhaust, if its a valve lying in the bilge its not a seacock.

We leave our main engine intake seacocks open all the time. I excersise them every couple of months. If we do close one or both of them for some reason we tape the power lever back with gaff tape and hang a sign on it that says the seacock for that engine is closed.

I installed red safety covers over the toggle switches that control the generator starter and our big AC salt water washdown pump. The flip-up covers say "seacock" on them. When I open the seacocks for these pieces of equipment we flip up the safety cover (we have to to operate the equipment) and leave that cover open until we close the seacock as a reminder on the AC panel that the seacock(s) are open.

Anode said:

He's gotta be talking about the raw water intake side. I'm 'pretty familiar' with the Sundowner 30 and there's no shut-off on the exhaust side.

Click to expand...

Yup, you're right.

Thanks for all the tips and advice,

Murray

This here's what I'm talking about;

ksanders said:

When I close my seacocks I put a "seacocks closed" notice attached to the ignition keys and the generator control panel.

Another very good thing about closing your seacocks is that movement keeps them operational. Seacocks seem to get stiff to a point of being inoperable through disuse. Using them insures they are in good working order.

Click to expand...

Same here. As an ex-submariner, I have an affinity for working thru-hull valves and close them if they are not required to be open.

Yes, I realize this is anal behavior.

The Coot's wet exhaust is several inches above the waterline portside of the engine compartment. No valve closing the exhaust line.

CPseudonym said:

The most dangerous thing on a boat IMO is a valve that is not regularly exercised. Regular exercise also keeps the operator intimately aware of their location and function in an emergency.

Click to expand...

Before someone post a photo of a valve on a lead going for a walk, I totally agree, closing them when leaving the boat for any appreciable time.
It is said here sailboats close them, powerboats leave them open; not me. And yes, valves like regular use. Not good forcing a valve,not knowing what might happen.

koliver said:

You actually have a seacock on your exhaust?
If the line is not self draining, I would close it. otherwise it seems extra.

Click to expand...

Depends if its a fully marinized engine doesn't it?. Mine isnt. The engine I have is a Perkins 6.354 Diesel. Whilst they have made full marine versions of the type of engine with built in heat exchanger, wet exhaust and some other minor things, they are basically the same. mine is out of a Qantas Airlines truck ( the ones that push the planes back so they can taxi ).

My exhaust will be bone dry. I wont have any running water through it at all. The system I will be running is a closed water system on the engine with sea water cooling. I have an external heat exchanger that runs fresh water coolant in her for the engine, I have a belt driven fynnspray sea water pump that will suck sea water up and push it in to and through the engine heat exchanger, the down and through to the gearbox heat exchanger and then over to and through the engine oil heat exchanger before exiting through a through hull right beside the cockpit. When the boats running, I will be able to just poke my head out the window and see a stream of water coming out.

Whilst I will have a seacock on the sea water intake, I won't be closing it if I'm on her. There's no real point is there? Unless a line fails then in which the auto bilge pumps will kick in and the high water alarm will sound if the pumps can't keep up. If I was to leave her on the mooring for an extended period of time then I'd shut it but yeah.

Regardless of leaving them open or closed. It's good practice to open and close them during the monthly checks to make sure they don't cease.

M2C

Sent from my iPad using Forum Runner

If you close an engine sea cock, simply hang the engine start key set on the valve handle.

Sailors with a mechanical prop lock use the same concept.

FF said:

If you close an engine sea cock, simply hang the engine start key set on the valve handle.

Click to expand...

I think we have a winner. Forwarding of prize contingent upon purchase of vessel

Hendo -- Your setup will still sink your boat if hoses or fittings go bad, no different than any other through hull drawing from below the waterline. Relying upon a bilge pump to operate for an extended period if not on shore power is foolhardy and optimistic if on shore power. (Even the Bounty's bilge pumps couldn't keep her afloat)

Bruce K's vessel is on a mooring with all through hulls properly closed, the only way to go in his case.

FF wins no prize from the many of us who have keyless push button start

FF said:

If you close an engine sea cock, simply hang the engine start key set on the valve handle...

Click to expand...

If you have only one helm.

It would be possible to attach a switch to the seacock handle and wire it to an alarm that would sound if the key was turned on whilr the seacock was closed.

Might as well just connect the switch to the starting circuit so it would be impossible to try to start the engine with the seacock off.

BruceK said:

Before someone post a photo of a valve on a lead going for a walk ...

Click to expand...

Your wait is over:

FF said:

If you close an engine sea cock, simply hang the engine start key set on the valve handle.

Click to expand...

What about the boats that have no key required? Mine has an engine switch on the panel and then an on switch at each of the helms. Flip the engine breaker. Go to a helm and flip the on switch and that activates the throttle control. Press the button on the throttle control and that activates the start switch for that helm. Start the engine. At any helm just press the button on the throttle to take control from that helm.

No keys required. But you do have to have a key to the boat to get in to flip the engine breaker on the panel.

I just do not close the seacock for my engine. Yes I do exercise all of them every month or so but close none of them when I'm away. That is why I pay the insurance policy yearly. Hell they need to have some exposure for what they charge.

RickB said:

Your wait is over:

Click to expand...

My wife does technical writing for everything from cosmetology to heavy equipment repair to funeral parlor operations to uranium processing. Many years ago on a heavy equipment project she first encountered the word "petcock". The next day she showed up at work with a small valve on a leash. I think you can fill in the rest.

bobofthenorth said:

My wife does technical writing for everything from cosmetology to heavy equipment repair to funeral parlor operations to uranium processing. Many years ago on a heavy equipment project she first encountered the word "petcock". The next day she showed up at work with a small valve on a leash. I think you can fill in the rest.

Click to expand...

Could have been worse.

sunchaser said:

Hendo -- Your setup will still sink your boat if hoses or fittings go bad, no different than any other through hull drawing from below the waterline. Relying upon a bilge pump to operate for an extended period if not on shore power is foolhardy and optimistic if on shore power. (Even the Bounty's bilge pumps couldn't keep her afloat)

Bruce K's vessel is on a mooring with all through hulls properly closed, the only way to go in his case.

FF wins no prize from the many of us who have keyless push button start

Click to expand...

*yawn* re-read what was written.

sunchaser said:

......... the many of us who have keyless push button start

Click to expand...

Isn't keyless push button start something that would make it easier to steal the boat?

I sometimes forget to remove my ignition key but my wife reminds me.

Hendon
Thank you very much for yawning. In re-reading your post I note (again) you indeed have a valved seawater through hull. So if any of the lines connected to it fail with the valve open, your boat will indeed take on lots of water relying upon your bilge pumps to keep it afloat. What am I missing?

R Widman

Of the many boat issues I have fretted over, boat theft is the last one. I'm more worried about losing the nav gear. Now if I had a decaled up Fountain parked in the Carolinas ----------------

sunchaser said:

R Widman

Of the many boat issues I have fretted over, boat theft is the last one. I'm more worried about losing the nav gear. Now if I had a decaled up Fountain parked in the Carolinas ----------------

Click to expand...

Very true...few trawler type or large boats are stolen due to how slow the getaway process is considering the USCG's flying assets.

Also...having been in the marine business now for over 12 years...the biggest joke is the more expensive the boat...the closer the hidden key is to the ignition as the greater the chance is the owner isd gonna have people working on it all week...