With the move to underwater exhausts, we have no visual indication of water flow in the exhaust system. We do have an electronic flow alarm on each engine, and temperature alarms on each injection elbow, but not seeing the water flow has made us uncomfortable. Thanks to Mark Fritzer we now have an answer.
The impeller in the bronze housing above gives us a good visual indication of water flowing. This is not cheap, costing close to $400 retail for each one. And at first we balked at the cost. But now that we have seen these in action, we’d fit them again even with an above-the-water exhaust system.
There are a couple of negatives. First, the pin on which the impeller rides is stainless steel. It will eventually go away, 316 not being particularly happy in salt over a long period of time. Next, the cover plate is mild steel and is going to rust. We’ll have to protect it in some fashion. The cover plate comes off and the glass can be removed, and the pin replaced.
We have mounted these in the salt water line just before the injection elbow of the exhaust system, well above the water line, where it should remain dry most of its life. That should help the wet stainless parts survive. Alternately, if immersed, this could be bonded to the engine and its zinc system to give the parts protection.
We shall report in a few months as to how these are holding up.
Posted by Steve Dashew (July 18, 2012)
July 18th, 2012 at 8:58 pm
Why not powder coat the cover plate?
July 18th, 2012 at 9:09 pm
Eventually that will happen. Problem right now is we are finished with testing and modeling for the 97 and are ready and anxious to go cruising.q
July 19th, 2012 at 10:14 am
Steve, who is the supplier/contact for this item?
July 19th, 2012 at 8:53 pm
John Ernst is the company the makes these and we purchased direct from them just Google their name)
July 19th, 2012 at 5:14 pm
Hi Steve,
I thoroughly concur with your concern re lack of visual on the exhaust cooling water even with parallel alarms systems.
I have used similar type flow sights for quite a while now and they are useful on a number of systems.
There is a wide variety of styles, materials and prices for these things. They are handy on hydronic heating circuits, a water heater circuit connected to an engine and a/c & refrigeration cooling pumps.In my opinion they are an essential addition to keel cooled systems or gensets with water separating exhausts.
I hope you get to escape the bonds of terra firma soon.
David