Engine waterlock and levels

[purplerobbie]

I have just fitted a Beta 25 to a rival.
I was looking at the exhaust and i'm a bit worried that the water that sits in the waterlock will run back into the engine.
The engine has a high exhaust injection bend thinghy and the waterlock is below the exhaust exit but not much.
The exhaust then runs up hill to a swan neck thinghy at the back and then out.
Can the water run back out of the pipe and the waterlock and into the engine?
If so how could i stop it?
Rob

Edit
Should there be a big u in the hose from the injection bend to the waterlock? Would that stop it or would that cause more problems?

Rob

 

[ShipsWoofy]

<span style="color:blue">I was looking at the exhaust and i'm a bit worried that the water that sits in the waterlock will run back into the engine. </span>

Only if the waterlock fails, this is the primary role of the water lock to prevent water backing up the system.

<span style="color:blue">Should there be a big u in the hose from the injection bend to the waterlock? Would that stop it or would that cause more problems? </span>

No, ideally the water lock should be as close as possible underneath the exhaust manifold. Adding a U will negate any benefit of having the waterlock at all. The waterlock does what it says on the tin, it is under normal conditions alike a one-way-valve, but unlike a rubber gator type valve, the lock can back flood and overflow hence the need for your swan-neck. For example, my exhausts are near the waterline, if we both stand above the exhaust the outlet will actually dip into the water. Without the swan-neck inside the boat, this would have water pouring into the exhaust pipe, into the lock. That much water could I think overwhelm the waterlock and make it's way into the engine.

The waterlock is designed to move the water away from the exhaust pipe and the swan neck to stop water entering from the outside. Two items, two jobs. I think, think, the water lock works by using chambers, the water left in the main pipe and the water in the manifold pipe falls into a lower baffled chamber, more like a reservoir to catch the excess, than a one way valve. <span style="color:red"> Someone please correct me if I am wrong </span>.

If you do not have one fitted, fit an anti-syphon valve into the system, this goes in place of the final seawater cooling pipe in the system, the pipe that goes from the engine to the exhaust manifold. This stops the system potential sucking water after the engine is stopped due to the syphon between the seacock and the lowest part of the exhaust. The vetus anti-syphon valve was about £35 (it may be half this, I had to buy 2, and don't remember if this was each or for both). Best buy in my opinion is the type with an dribble outlet through the hull or into your cockpit drain. The sealed type requires regular cleaning in salt water as they bung up.

hope this helps.

 

[Csail]

I wrecked the old engine because i must have loaded the boat more than the last owner which put it about aninch lower in the water which caused it to syphon back and flood the engine. Put a vetus anti syphon valve in te system.

 

[fisherman]

These people have the answers

 

[jon]

You might find these Vetus instuctions and diagrams useful:

http://www.vetusweb.com/manuals/files/Exhaust_systems/030412%20r02%2003-03.pdf

 

[cliffordpope]

The critical factor regarding the anti-syphon valve is the height of the injection point with respect to the waterline. If above (in all loading circumstances) then it can't syphon. If below, then it could.
I don't think the run of the exhaust pipe beyond the injection point comes into this aspect of the design. (see the difference between Vetus diagrams 2 and 3)

 

[jerryat]

[ QUOTE ]
The critical factor regarding the anti-syphon valve is the height of the injection point with respect to the waterline. If above (in all loading circumstances) then it can't syphon. If below, then it could.
I don't think the run of the exhaust pipe beyond the injection point comes into this aspect of the design. (see the difference between Vetus diagrams 2 and 3)

[/ QUOTE ]

Yes, I agree with you. However, on my installation, where the W/L is only about 150mm below the injection point, I have installed exactly the same system as shown on Vetus website (link in previous post) on page 15.

This gives me the confidence that, in big following seas and with the boat well heeled, no water can reach the engine via syphoning or back-pressure.

Westerly didn't fit this system from new, so I stripped out what was there to install it. It's been in place for over 18 years now and has worked perfectly. No company connections etc.

 

[30boat]

I have an instalation very much like the one on the Vetus diagram only I made the anti siphon thinghie myself thus saving a few good $$$.I used a SS tube bent in a half a circular shape with an outlet pipe welded on top that is connected to a hose that goes to a fitting on the transom.There's always a telltale dripping from there and it's a good indicative of how things are working.

 

[jerryat]

Hi 30boat!

Excellent idea! I'm afraid that if you ever saw MY efforts at welding though, you'd agree that I was far safer buying the Vetus bits!! /forums/images/graemlins/smile.gif /forums/images/graemlins/smile.gif