Simon says: Are you my mummy?

I mentioned a few blog entries ago that I’m thinking about upgrading my vessel monitoring system – called Simon.

My primary interest is in seeing if I can monitor the sea water that is flowing to the various equipment that needs cooled (gensets, air conditioning compressors, hydraulics, and not to be forgotten – the main engines). Our trip to Costa Rica taught us that, in warm water, crud grows and clogs the lines much faster than one can imagine. We actually were very lucky. On our very last arrival into Golfito, after a couple weeks at anchor, our intakes to the seachest clogged, causing the seachest to fill with air, causing an instant failure in the hydraulic system. I had just played thread the needle, bringing the boat around a zillion dollar megayacht, in order to reach our slip. Had I been blindsided by thruster failure, there’s a chance that the current in the marina would have grabbed me, and both I and the megayacht would have had a bad day.

Currently, there is really no way to know if the hoses that carry sea water are clogged. On several occasions, I had the hoses cleaned, only to find that the clog was elsewhere in the system, and I was kidding myself to think I had found it. My hope is that I can find a way to know well in advance if there is clogging, and even be able to quantify it, in terms of lost gallons per hour.

When my boat was being built, I asked the Simon people about monitoring fluid flow, and they said they weren’t recommending it. The problem is that adding a “paddle wheel” to a hose introduces a new item to the system that is itself prone to failure. Mike Blake, President of Palladium Technologies, makers of Simon, mentioned at the time that he was experimenting on his own boat with ultra sonic sensors that could measure fluid flow within a hose, without impeding the flow of liquid. I said “Sounds great! I want it!” and he said “Not yet. This is experimental.”

The Ft Lauderdale boat show is now in progress, and a friend, Steven Argosy of Seabird is at the show. I asked him to hunt down Mike Blake and check on where the current “state of the art” is with respect to measuring fluid flow. Steven called back, and said that he had spoken with the Simon people, and that they do not recommend measuring fluid flow, because the paddle wheels tend to get gunked up. I relayed to him my story about Mike Blake and the ultra-sonic sensors, and he went back to the booth on a Mike-quest. Happily, he tracked him down, and Mike said that the ultra sonic sensors do in fact exist, and that they are still considered experimental, but, that he would be writing me about installing them on my boat. That’s great news! We’ll see where it goes, but my hope is to get an early warning if there is clogging in any cooling system.

And, on a different topic…

Roberta and I had a “fun” discussion at dinner. I mentioned to her that I had just read an article on Papua New Guinea in a french magazine. We have been somewhat interested in learning about Papua New Guinea because two circumnavigating boats in a row, that I have spoken with, have said that their favorite cruising grounds in the whole world were Papua New Guinea.

The subject of this particular article caught my attention. The article was titled: “In Papua New Guinea, the Mummys are protected.” And, subtitled, “The chief of the Anga, persuaded that abandoning cadavers of their ancestors is the cause of his tribes problems, is giving them their dignity by restoring them., and is preparing their mummification, even after this rite has been forbidden for 50 years.”


The picture caption says: “The mummys of the
warriors watch forever at the entrance to the village”

 

An interesting article, but it was impossible to not think “If this is the best we have to look forward to, what does the worst look like?”

-Ken W

PS The latest update I have on weather indicates that Sans Souci will not be able to begin its’ final leg home until Wednesday.

4 Responses

  1. Ken, Ultrasonic flow meters have been used for about 15 years in the industrial, chemical, oil and water treatment industries. We have used them under some very extreme conditions such as caustic gases, steam and of course salt water. A little background of how they work and why we filed for patents in the marine industry. The Ultrasonic flow meters can be used to monitor any fluid or gas with a very high accuracy rate and are of course non-invasive (clamps to the outside of a pipe).

    Two types of Ultrasonic are used depending on the material that is flowing through the pipe. First is the Doppler Ultrasonic meter, it similar to your depth or fish finder. The flow meter transmits an ultrasonic sound from its transmitting transducer into the flowing liquid. The sound will be reflected by sonic reflectors (gas bubbles or particulate) suspended within the liquid and recorded by the receiving transducer. If the sonic reflectors are moving within the sound transmission path, sound waves will be reflected at a frequency shifted (Doppler frequency) from the transmitted frequency. The shift in frequency will be directly related to the speed of the moving particle or bubble, resulting in a liquid flow rate that is interpreted by the meter and sent to a user interface (LCD display typically) in some type of measuring units.

    The other type of ultrasonic meter is the Transit time meter. (We use this type for clean water such as fresh on-board water and raw water cooling systems). This flow meter operates by transmitting and receiving a frequency modulated burst of sound energy between two transducers. The burst is first transmitted in the direction of flow then against the flow. Since sound energy in a moving liquid is carried faster when it travels in the direction of fluid flow (downstream) than it travels against the flow, a difference in the travel times will occur. This difference between the two travel times is then calculated to measure the flow rate.

    The Aqua-Sonar system we offer can send a 4-20 mA output to the Simon system, Night-watch or other systems that have inputs available.

    The Aqua-Sonar system is used for Raw water, fresh water, Diesel fuel and oil to give low flow alarms, fuel totals and schedule service for these systems.

    The system needs to know the OD of the pipe, the ID of the pipe, the wall thickness, type of material the pipe is made of. The programing of the ultrasonic characteristics of the material and thickness is crucial to the accuracy of the meter.

    Now with all this said, the trick to making the system work properly once its programed is understanding hydrodynamics. For the best accuracy and consistency we must know where to attach the clamp on transducers. Ah ha! that’s the magic. If it’s installed correctly it will last for years and will be reliable. Know your flow characteristics before you attempt the install or it will be no better than a paddle wheel flow meter.

    By the way, I have been installing these kinds of devices and selling fluid control devices for nearly 30 years. I love it and welcome anyone interested in improving the reliability and safety of there vessel.

    For more info you can contact me at CleanMarineSystems.com (http://CleanMarineSystems.com) or at 800-708-5730.

  2. I do think I will install a level indicator in the seachest, but see it as only one piece of the solution. My seachest has two large intakes, and about six hoses coming out of it (genset 1, genset 2, ac/cooling, hydraulic cooling, watermaker 1, watermaker 2). Let’s say that the hydraulic cooling pump failed, or the line clogged. Until the stabilizers fail, or I get an alarm that the hydraulic system is overheating, I wouldn’t know. Unless an intake line clogs, I could have a problem, yet the seachest still be full of air, and all appear to be well.

    The idea of being able to see the flow stated as a “gallons per hour” seems good to me. My Simon monitoring system is good at being able to track things to a range. So, if I notice that 5gph is “normal” I’ll set the range on Simon as 4 to 6GPH, and I’ll know immediately if the flow is high or low.

    I don’t know if it is more reliable to measure the pressure in the hoses, or the flow through the hoses. I just wrote to the Simon people late last week, and my friend Steven just approached them yesterday. They are preparing a formal recommendation to me, and I’m not sure what it will say. As soon as I get it, I’ll be posting on my blog what they think I should do.

    Thanks! – Ken W

  3. Beware, ultrasonic flow meters (and other non-intrusive technologies like electro-magnetic inductive sensors) measure the speed of the fluid and compute volume based on the diameter of the pipe. This assumes a constant diameter, but if the diameter is changing due to growth, you aren’t going to get an accurate volume reading. You might be better off doing a differential pressure measurement (measure pressure at both ends of the system) where you can watch the differential pressure to determine if the system is clean (low differential) or dirty (high differential).

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Credits     |     Video produced by: Rock Steady Media     |     Teletype photo: Arnold Reinhold     |     PDP-11 photo: Trammell Hudson