Stability Monitoring Device for Fishing Vessels

Discussion in 'Stability' started by Freeboard Joe, Feb 17, 2017.

  1. Freeboard Joe
    Joined: Feb 2017
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    Freeboard Joe New Member

    I am trying to find companies that manufacture real-time stability monitoring devices that can be installed on the bridge of fishing vessels (up to 45 m). When vessels capsize due to stability problems they do so in seconds leaving no time for crew members to don immersion suits or life jackets. Consequently, lives are often lost. I'm hoping that somewhere in the world there exist working stability monitoring devices that can warn vessel operators of dangerous stability characteristics in time for corrective action to be taken to save the vessel. I'd be grateful for your input.
     
  2. TANSL
    Joined: Sep 2011
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    TANSL Senior Member

    This is called a "Loading Instrument" and is mandatory for many types of ships, such as oil tankers or container ships, among others.
    If a ship can sink so fast that the crew can not put on life jackets, there are two solutions:
    - finally sink the boat before anyone can drown.
    - that the crew always go with the lifeboat.
    I know that a ship badly loaded and badly closed, because of a badly taken wave, can sink quickly but this cause of shipwreck can't be avoided by any mechanism.
     
  3. Freeboard Joe
    Joined: Feb 2017
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    Freeboard Joe New Member

    Fishing Vessel Stability Monitor

    Thanks TANSL. I'll research 'Loading Instruments'. Unlike a cargo ship, a fishing vessel's stability characteristics can change dramatically and instantly while at sea. Nets containing 20 T or more of fish are often hauled aboard many times a day and distributed into port, starboard, forward, aft and/or centreline tanks which are already filled to varying levels with refrigerated sea water. During the loading process, hatches must be open to receive fish. Lots can go wrong in a hurry. A device that could emit audio and visual alarms in the event that transverse stability characteristics were approaching a dangerous condition could leave time for the master or mate to take effective corrective action before it's too late.
     
  4. Ilan Voyager
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    Ilan Voyager Senior Member

    For fishing boats the worst and fastest accident is when the trawling nets catch a reef, a shipwreck or at least in one case a submarine. That can capsize the boat in less than 2 minutes.
    On a well designed fishing boat the fish is kept in many different tanks (the ice cold sea water is called Portuguese system) and none of them is big enough to capsize the boat even totally filled by the sea water of a wave running on the deck. Besides there must be enough openings to empty the deck in seconds.
    The work of the master is to open only the needed hatches keeping in mind the stability. So I would see (I may be wrong) a device that forbids too many open hatches in the same side for example. I'm almost sure that such a device is already in use at least on the European boats.
    The other device is an alarm when the heeling is approaching a dangerous level because of the waves. It's a rather simple device. Capsize is often a dynamic occurrence, and a mistake of the captain.
    20 tons (!!!!) of fish is only for very big open stern trawlers... These boats are not often in risk, unless total human error.
    The more in danger are the small trawlers in very agitated coastal waters while taking the net by the side, not when opening the hatches as the fishermen have to sort the fishes before. An inclinometer would do the job.
     
  5. CDK
    Joined: Aug 2007
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    Location: Adriatic sea

    CDK retired engineer

    A number of years ago we had a car ferry equipped with digital loading instruments. Large displays on the port and starboard side showed the waterline depth, so the crew could see where to put heavy trucks to keep the vessel level. A complete waste of money because the crew never paid attention to the values on the displays.

    Would an audible warning be better ? I doubt it. With sirens sounding each time when the ferry left the shelter of a nearby island there would be some panic until everybody got used to it and would from then on ignore the sirens.
     
  6. TANSL
    Joined: Sep 2011
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    TANSL Senior Member

    As others have pointed out, a real-time alarm system can be even counterproductive. What the fishing master must always know is what he can and can not do and for that the "loading instrument" may be the right tool. Before beginning any maneuver, the fishing master must know if it is dangerous and, therefore, do not do it. He must know that, if he exceeds certain limits, he must interrupt the maneuver immediately. Some way to check those limits could be helpful.
    The stability conditions are 90% similar to those of any other ship but have, as you pointed out, certain specific maneuvers that must be studied from the point of view of stability (for fishing vessels and for any other type of vessel). There is what is called the "Stability Booklet", which must be approved by the competent maritime authority, which includes such studies and which the master is obliged to comply with and, above all, is obliged not to perform maneuvers not studied in the booklet.
    The stability booklet is a document that must be signed by the master, at the reception of the ship, ensuring that he understands it and agrees to comply. In this document, moreover, there are procedures so that the captain can determine at certain moments, quickly, if the boat exceeds the permissible conditions (for example, the limiting KG curve).
    Everything is improveable, of course, but things are, in general, well studied and regulated.
     
  7. Freeboard Joe
    Joined: Feb 2017
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    Freeboard Joe New Member

    Thanks. I'm posting a link to the Canadian Transportation Safety Board (TSB) report of the capsizing and sinking of a trawler on the west coast of British Columbia Canada in September 2015 with the loss of three lives. The report is well written and tells the story how multiple causes are involved in creating a single accident. On the prevention side, my contention is that stability books are not useful in real time when the vessel is heeling over. An inclinometer only records conditions as they occur - it has no capacity to warn of impending danger. I'm looking for the kind of electronic warning information analogous to that provided by Cross Track Error (XTE) on radar. Anyone who is interested will note that in the report that the last single haul when the accident occurred was 15 T.
    http://www.tsb.gc.ca/eng/rapports-reports/marine/2015/m15p0286/m15p0286.pdf
     

  8. JSL
    Joined: Nov 2012
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    JSL Senior Member

    I have read this TSB report & went to the Feb. 8 'Fishsafe' meeting in Richmond BC. where the major contributing factors (there were several) were presented and discussed. It should be noted that one crew member survived as he was the only crewmember wearing a lifejacket.
    There are stability monitors being tested and one may have prevented this accident.
    You can check out www.stabilitysolutions.com who have been developing a device for the past few years.
     
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