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11-09-2019, 16:27
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#1
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Registered User
Join Date: Jan 2015
Location: Seattle, WA
Boat: 1980 Pacific International Marine 41.5
Posts: 710
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Methods to reduce water sitting in exhaust and preventing hydrolocking
So as I am awaiting my turbo rebuild, I am trying to think through on what caused the problems, what problems are down stream of the engine and ways I can prevent future issues from occurring.
I recieved a new mixing elbow and as such wanted to compare the old to the new. When I pulled the elbow out of the exhaust hose, I realized the hose running from the elbow to the lift riser(?) has standing water. First, I believe this may be due to the angle that the hose runs from the elbow to the riser, but I believe this also is due to possibly the riser not being large enough?
Does anyone have any recommendations on resources for how a proper exhaust system be installed?
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11-09-2019, 16:55
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#2
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Registered User
Join Date: Jan 2012
Location: Long Island, New York
Boat: Beneteau 423 43 feet
Posts: 851
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Re: Methods to reduce water sitting in exhaust and preventing hydrolocking
Picture........ more the better
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11-09-2019, 17:45
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#3
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Registered User
Join Date: Nov 2014
Posts: 1,620
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Re: Methods to reduce water sitting in exhaust and preventing hydrolocking
Lots of info out there on water lift mufflers.... Google "water lift muffler installation", or check out "Centek.com", etc..
For sure there should be no sagging hoses or standing water in the hose from the exhaust elbow to the water lift muffler, and generally no more than an inch or two standing water in the bottom of the muffler itself upon engine shutdown.
DougR
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11-09-2019, 18:56
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#4
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Registered User
Join Date: Jan 2005
Location: On board
Boat: Van de Stadt 50'
Posts: 1,409
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Re: Methods to reduce water sitting in exhaust and preventing hydrolocking
The riser diameter should be smaller in the rise, then larger downhill to the outlet. You need to accelerate the gasses in that run. All uphill small, all downhill big.
Sometimes wind and "breathing" happens and salty air can be blown through the engine. This will create rust. Best is to install an inline flapper valve, like a non-return valve.
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12-09-2019, 05:27
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#5
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Senior Cruiser
Join Date: Mar 2003
Location: Thunder Bay, Ontario - 48-29N x 89-20W
Boat: (Cruiser Living On Dirt)
Posts: 49,559
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Re: Methods to reduce water sitting in exhaust and preventing hydrolocking
__________________
Gord May
"If you didn't have the time or money to do it right in the first place, when will you get the time/$ to fix it?"
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12-09-2019, 05:53
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#6
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Registered User
Join Date: Sep 2009
Location: Houston
Boat: ‘01 Catana 401
Posts: 9,626
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Re: Methods to reduce water sitting in exhaust and preventing hydrolocking
Quote:
Originally Posted by GordMay
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The only problem I’ve got with those diagrams is they’re not designed for a craft that heels. The waterlift should be centerline when the boat is able to heel without the engine running.
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12-09-2019, 09:44
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#7
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Registered User
Join Date: Oct 2007
Location: Charleston, SC
Boat: Stevens 47
Posts: 199
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Re: Methods to reduce water sitting in exhaust and preventing hydrolocking
Quote:
Originally Posted by Sailmonkey
The only problem I’ve got with those diagrams is they’re not designed for a craft that heels. The waterlift should be centerline when the boat is able to heel without the engine running.
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I believe that all of the systems illustrated are intended to be installed on the centerline of the vessel. The illustrations are a little misleading in that the transom thru which the exhaust exits looks a lot like the side of a boat rather than the stern.
The most important element of exhaust system design for a sailboat is that the outlet of a waterlift muffler must go straight up to a point above the water line before making a 180 turn and heading for the stern.
I just rebuilt a Ford Lehman 120 that was flooded due to a failure to route the exhaust straight up as I've described. Obviously, we're fixing that problem now.
Scott
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12-09-2019, 11:32
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#8
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Registered User
Join Date: Nov 2009
Location: State of Washington
Boat: Tayana 37 Pilot House
Posts: 153
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Re: Methods to reduce water sitting in exhaust and preventing hydrolocking
Quote:
Originally Posted by sy_gilana
..........Sometimes wind and "breathing" happens and salty air can be blown through the engine. This will create rust. Best is to install an inline flapper valve, like a non-return valve.
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Exhaust flapper valves need periodic inspection and rarely receive it! After several years they are known to become unhinged (literally), rendering them useless and sometimes causing partial obstruction. Better yet is to dispense with the flap valve and install a full-bore diameter ball valve at or near the exhaust exit.
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12-09-2019, 17:03
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#9
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Registered User
Join Date: Jun 2012
Location: argyle, nova scotia
Boat: 30 feet sailboat, 1991
Posts: 142
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Re: Methods to reduce water sitting in exhaust and preventing hydrolocking
my engine is low in the boat and there is no room for the minimum clearances on the usual diagrams. I just shut the seawater intake off two minutes before the engine shuts down. This clears the exhaust system of water, and I have a flapper valve on the stern
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12-09-2019, 19:16
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#10
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Moderator Emeritus
Join Date: Oct 2013
Location: Jacksonville/ out cruising
Boat: Island Packet 38
Posts: 31,351
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Re: Methods to reduce water sitting in exhaust and preventing hydrolocking
Quote:
Originally Posted by peter loveridge
my engine is low in the boat and there is no room for the minimum clearances on the usual diagrams. I just shut the seawater intake off two minutes before the engine shuts down. This clears the exhaust system of water, and I have a flapper valve on the stern
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Surprised you haven’t had multiple Impeller failures.
I was going to suggest a ball valve after the pump, close it, rev the engine like Yanmar suggests anyway and shut it down.
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12-09-2019, 20:02
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#11
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Registered User
Join Date: Feb 2013
Location: Oregon
Boat: Seafarer36c
Posts: 5,563
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Re: Methods to reduce water sitting in exhaust and preventing hydrolocking
Quote:
Originally Posted by peter loveridge
my engine is low in the boat and there is no room for the minimum clearances on the usual diagrams. I just shut the seawater intake off two minutes before the engine shuts down. This clears the exhaust system of water, and I have a flapper valve on the stern
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How many times would I have sunk our boat if it had that set -up? Good for you sir
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13-09-2019, 08:32
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#12
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Marine Service Provider
Join Date: Jun 2016
Posts: 321
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Re: Methods to reduce water sitting in exhaust and preventing hydrolocking
If you'd like to contact me direct at jmardall@comcast.net, I'll send you the Vetus Academy training module on wet exhaust systems, which covers these issues extensively.
All the best
John Mardall
Vetus Maxwell Boat Equipment
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13-09-2019, 09:26
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#13
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Registered User
Join Date: Sep 2015
Location: East Coast Florida
Boat: Chris Craft 38 Commander 1965
Posts: 482
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Re: Methods to reduce water sitting in exhaust and preventing hydrolocking
A lot of good info in the above replys.
Take a look on the Seaboard Marine website ( sbmar.com ) for ideas and pictures and videos about preventing turbo death. Whatever protects the turbo protects the Elbow at the same time.
Go to the tab marked under Tony's Tips.
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13-09-2019, 16:33
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#14
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Registered User
Join Date: Jan 2015
Location: Seattle, WA
Boat: 1980 Pacific International Marine 41.5
Posts: 710
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Re: Methods to reduce water sitting in exhaust and preventing hydrolocking
Yup, that was what I was thinking, if I protect the elbow, the turbo inherently is protected( and viceversa).
Sbmar has some great info - just started looking at that.
Tine to start digging around, measuring and determining where water levels are figuring out how to make ours better as its obvious water is sitting in the exhaust and in turn causing the rot to occur.
Quote:
Originally Posted by Squanderbucks
A lot of good info in the above replys.
Take a look on the Seaboard Marine website ( sbmar.com ) for ideas and pictures and videos about preventing turbo death. Whatever protects the turbo protects the Elbow at the same time.
Go to the tab marked under Tony's Tips.
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13-09-2019, 21:34
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#15
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Registered User
Join Date: May 2013
Location: Oregon to Alaska
Boat: Wheeler Shipyard 83' ex USCG
Posts: 3,525
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Re: Methods to reduce water sitting in exhaust and preventing hydrolocking
I have valves on my water mufflers that open when the pressure of the exhaust is gone as the engine is shut down. That way the engine starts with low back pressure, handy with an older engine. Also you can crank for awhile without worrying about water building and flowing into the engine. Since the engine is stopped, the muffler drain is open.
I don't like turbo engines, and if I have the hp I need available in a natural, I go that way. But I've owned many turbos and ran many others. I solve the problem of early turbo failure by replacing the turbo bearings and seals at about half life. A lot cheaper than a new/rebuilt turbo and easy to do. Also clean oil. Turbo bearings either get their lube oil thru a small passage in the head or an outside tube. The oil cools the bearings. Dirty oil leaves deposits restricting the flow. If the flow is reduced too much the bearings get too hot, degrade over time and enough heat will ruin the seals.
I just rebuild my Ford PU turbo for about $100.
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