Topics

Strainer air lock

Patrick McAneny
 

Sailing back from Bermuda last spring , my engine would shut down and I discovered that there was no water in my strainer ,thus the engine had no water and shut down. We were sailing in only moderate to strong conditions ,but never heeled beyond 20 degrees. When I opened the strainer lid water would flow to the top, and I could motor once again. This same thing happened repeatedly ,and had never happened prior to this trip. I made a change to the cooling system in Bermuda, and I want to know if this may have caused this air lock .
Upon starting any boat engine, I have always checked the exhaust for water flow. However on my Amel the exhaust is at water level making it impossible to see if cooling water is flowing. When a couple of owners a while back posted that they had a small hose streaming cooling water into the cockpit confirming flow, I wished I had that set up,Amel must of added this feature to newer models.
So in Bermuda I took off the anti siphon valve off the loop at the top of the hose from the heat exchanger to the exhaust elbow. In place of the valve I ran a small hose to my cockpit scupper to show me water flow. It worked only marginally well ,I surmise most of the water flow never rises to the top of the loop. I figured it still served as a siphon break as it is open to the atmosphere . My question is ,could this have allowed all the water to flow back out of the engine and strainer while heeled over and create an air lock ? Secondly has anyone have a photo of how this system is installed ,I would like to replicate it.
Thanks,
Pat
SM Shenanigans

Ryan Meador
 

We've experienced something like this.  For us, the problem was air leaking into the low pressure (suction) side of the system, not the high pressure side.  The gasket on the raw water strainer was not sealing well.  We fixed it by greasing it well with silicone grease and tightening it down.  Really we probably need to replace the gasket (add it to the todo list).  The problem seems to get worse when the inflow is restricted, so you might want to check the strainer and thru-hull for barnacles and that sort of thing.

I doubt the hose you added to the anti-siphon valve is the cause.  Your description of what you did is almost exactly what the Amel setup is.  If water isn't flowing out, it's probably because water isn't flowing through your engine.

Ryan and Kelly
SM 233 Iteration
Boston, MA, USA


On Tue, Mar 3, 2020 at 7:38 PM Patrick McAneny via Groups.Io <sailw32=aol.com@groups.io> wrote:
Sailing back from Bermuda last spring , my engine would shut down and I discovered that there was no water in my strainer ,thus the engine had no water and shut down. We were sailing in only moderate to strong conditions ,but never heeled beyond 20 degrees. When I opened the strainer lid water would flow to the top, and I could motor once again. This same thing happened repeatedly ,and had never happened prior to this trip. I made a change to the cooling system in Bermuda, and I want to know if this may have caused this air lock .
Upon starting any boat engine, I have always checked the exhaust for water flow. However on my Amel the exhaust is at water level making it impossible to see if cooling water is flowing. When a couple of owners a while back posted that they had a small hose streaming cooling water into the cockpit confirming flow, I wished I had that set up,Amel must of added this feature to newer models.
So in Bermuda I took off the anti siphon valve off the loop at the top of the hose from the heat exchanger to the exhaust elbow. In place of the valve I ran a small hose to my cockpit scupper to show me water flow. It worked only marginally well ,I surmise most of the water flow never rises to the top of the loop. I figured it still served as a siphon break as it is open to the atmosphere . My question is ,could this have allowed all the water to flow back out of the engine and strainer while heeled over and create an air lock ? Secondly has anyone have a photo of how this system is installed ,I would like to replicate it.
Thanks,
Pat
SM Shenanigans

Patrick McAneny
 

Ryan, I will keep that in mind ,if / when it happens again. Problem is there is no way to check it until I am in strong enough conditions to be heeled 20 degrees or so to port. I agree that it does not seem that what I did ,taking out the anti siphon valve would create a condition ,where I would lose water out of the strainer. But that was the only thing I had done or changed. A small amount of water spits out occasionally, and I am pumping water since the engine is not overheating. I just think that the water level does not fill the elbow to the top . Do you have that set up,if so where does the hose connect to the cooling system.
Thanks,
Pat
SM Shenanigans


-----Original Message-----
From: Ryan Meador <ryan.d.meador@...>
To: main <main@amelyachtowners.groups.io>
Sent: Thu, Mar 5, 2020 5:11 pm
Subject: Re: [AmelYachtOwners] Strainer air lock

We've experienced something like this.  For us, the problem was air leaking into the low pressure (suction) side of the system, not the high pressure side.  The gasket on the raw water strainer was not sealing well.  We fixed it by greasing it well with silicone grease and tightening it down.  Really we probably need to replace the gasket (add it to the todo list).  The problem seems to get worse when the inflow is restricted, so you might want to check the strainer and thru-hull for barnacles and that sort of thing.

I doubt the hose you added to the anti-siphon valve is the cause.  Your description of what you did is almost exactly what the Amel setup is.  If water isn't flowing out, it's probably because water isn't flowing through your engine.

Ryan and Kelly
SM 233 Iteration
Boston, MA, USA


On Tue, Mar 3, 2020 at 7:38 PM Patrick McAneny via Groups.Io <sailw32=aol.com@groups.io> wrote:
Sailing back from Bermuda last spring , my engine would shut down and I discovered that there was no water in my strainer ,thus the engine had no water and shut down. We were sailing in only moderate to strong conditions ,but never heeled beyond 20 degrees. When I opened the strainer lid water would flow to the top, and I could motor once again. This same thing happened repeatedly ,and had never happened prior to this trip. I made a change to the cooling system in Bermuda, and I want to know if this may have caused this air lock .
Upon starting any boat engine, I have always checked the exhaust for water flow. However on my Amel the exhaust is at water level making it impossible to see if cooling water is flowing. When a couple of owners a while back posted that they had a small hose streaming cooling water into the cockpit confirming flow, I wished I had that set up,Amel must of added this feature to newer models.
So in Bermuda I took off the anti siphon valve off the loop at the top of the hose from the heat exchanger to the exhaust elbow. In place of the valve I ran a small hose to my cockpit scupper to show me water flow. It worked only marginally well ,I surmise most of the water flow never rises to the top of the loop. I figured it still served as a siphon break as it is open to the atmosphere . My question is ,could this have allowed all the water to flow back out of the engine and strainer while heeled over and create an air lock ? Secondly has anyone have a photo of how this system is installed ,I would like to replicate it.
Thanks,
Pat
SM Shenanigans