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  • Damage Stability

    Wondering if someone can help. I was reading through past orals and the question posed is What are the intact stability requirements? Now I’m assuming the answer was 0.15m GM etc etc The next question was then what are the damage stability requirements for your last ship? I have got my current ships stability booklet and plan out and can not find any specific figures that I could quote for this. Any chance someone could give me an example of how they would answer this question in an oral so I can see what exactly they would be looking for? Cheers

  • #2
    Hi mate I noticed you asking for digital study notes and I wondered if you ever got any. I'm due to do mates masters at Glasgow or warsash and if you could email me anything you have, I'd be mighty grateful.
    Regards mark
    wonkystonky@hotmail.com

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    • #3
      Originally posted by Mantaforce View Post
      Wondering if someone can help. I was reading through past orals and the question posed is What are the intact stability requirements? Now I’m assuming the answer was 0.15m GM etc etc The next question was then what are the damage stability requirements for your last ship? I have got my current ships stability booklet and plan out and can not find any specific figures that I could quote for this. Any chance someone could give me an example of how they would answer this question in an oral so I can see what exactly they would be looking for? Cheers
      What type of ship was your last ship?

      Damage Stability requirements are based upon survivability and vary depending on type of vessel and keel laying date.
      “Twenty years from now you will be more disappointed by the things you didn’t do than by the ones you did do. So throw off the bowlines, sail away from the safe harbor. Catch the trade winds in your sails. Explore. Dream. Discover.”

      – Mark Twain
      myBlog | @alistairuk | flickr | youtube Views and opinions expressed are those of myself and not representative of any employer or other associated party.

      Comment


      • #4
        Originally posted by alistairuk View Post

        What type of ship was your last ship?

        Damage Stability requirements are based upon survivability and vary depending on type of vessel and keel laying date.
        Hi Alastair,

        Its an ERRV. I can see there are regulations for offshore ‘supply’ vessel mentioned in the damage stability booklet but no actual figures I could give in an answer

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        • #5
          Cant help you specifically with ERRV, but Damage Stability requirements (as applicable to vessels constructed now) are contained in the various regulations of SOLAS II-1 as well as explanations of the calculations.

          If your ship was constructed before the new rules came into force then it will be based upon sustaining damage of a certain percentage of its length (one fifth rings a bell) and up to 25% of its breadth and requiring not to submerge the margin line. (Passenger ships have additional requirements to do with cross flooding and compartmentalization and safe return to port).

          I'd assume your stability notes will have this specified somewhere if you need it I can go find mine, but I'm not on the ship at the moment so I don't have access to SOLAS.
          “Twenty years from now you will be more disappointed by the things you didn’t do than by the ones you did do. So throw off the bowlines, sail away from the safe harbor. Catch the trade winds in your sails. Explore. Dream. Discover.”

          – Mark Twain
          myBlog | @alistairuk | flickr | youtube Views and opinions expressed are those of myself and not representative of any employer or other associated party.

          Comment


          • #6
            Originally posted by alistairuk View Post
            Cant help you specifically with ERRV, but Damage Stability requirements (as applicable to vessels constructed now) are contained in the various regulations of SOLAS II-1 as well as explanations of the calculations.

            If your ship was constructed before the new rules came into force then it will be based upon sustaining damage of a certain percentage of its length (one fifth rings a bell) and up to 25% of its breadth and requiring not to submerge the margin line. (Passenger ships have additional requirements to do with cross flooding and compartmentalization and safe return to port).

            I'd assume your stability notes will have this specified somewhere if you need it I can go find mine, but I'm not on the ship at the moment so I don't have access to SOLAS.
            Thanks for getting back to me Alastair, this is slowly beginning to make more sense to me.

            The ship i'm on at the moment was constructed in 2014. In our damage booklet it states Damage Length = 3m + 3% / 3m + 0.03x64.8 = 4.994m

            Does this make sense to you? Would this 4.9m be what you mentioned about damaging a certain percentage of the ships length?

            Our damage stability requirements keep mentioning 'at the final stage of flooding'. I'm maybe just not thinking about this in the correct way but I'm struggling to understand what exactly that means, as in the whole engine room flooded? Our ER is separated into 3 compartments via the watertight doors - steering gear, main ER and bow thruster room but separate compartments don't seem to be mentioned in our damage stability requirements.

            I appreciate you taking the time to respond, I'm sorry if I'm coming across as a complete donkey in my understanding of this. I'm basically self studying for my Mate 3000gt and trying to catch up with everything after having my feet up on an ERRV is taking it's toll.

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            • #7
              Originally posted by Mantaforce View Post

              Thanks for getting back to me Alastair, this is slowly beginning to make more sense to me.

              The ship i'm on at the moment was constructed in 2014. In our damage booklet it states Damage Length = 3m + 3% / 3m + 0.03x64.8 = 4.994m

              Does this make sense to you? Would this 4.9m be what you mentioned about damaging a certain percentage of the ships length?

              Our damage stability requirements keep mentioning 'at the final stage of flooding'. I'm maybe just not thinking about this in the correct way but I'm struggling to understand what exactly that means, as in the whole engine room flooded? Our ER is separated into 3 compartments via the watertight doors - steering gear, main ER and bow thruster room but separate compartments don't seem to be mentioned in our damage stability requirements.

              I appreciate you taking the time to respond, I'm sorry if I'm coming across as a complete donkey in my understanding of this. I'm basically self-studying for my Mate 3000gt and trying to catch up with everything after having my feet up on an ERRV is taking it's toll.
              If it states 4.994m then your ship is required to survive flooding as a result of a hole that is 4.994m in length anywhere on the ships hull. I assume your ship is probably a "two compartment" ship, in that it is designed to survive with any two compartments flooded and not submerge the margin line (this is based on a hole 4.994m in length isn't going to cover more than 2 compartments - worse case if it occured right at the bulkhead between two).

              Final stage of flooding, just means the final condition that the ship would be in once it has fully flooded - it doesnt take into account the fact that the condition will be different during flooding until it reaches the "final stage".
              “Twenty years from now you will be more disappointed by the things you didn’t do than by the ones you did do. So throw off the bowlines, sail away from the safe harbor. Catch the trade winds in your sails. Explore. Dream. Discover.”

              – Mark Twain
              myBlog | @alistairuk | flickr | youtube Views and opinions expressed are those of myself and not representative of any employer or other associated party.

              Comment


              • #8
                Originally posted by alistairuk View Post

                If it states 4.994m then your ship is required to survive flooding as a result of a hole that is 4.994m in length anywhere on the ships hull. I assume your ship is probably a "two compartment" ship, in that it is designed to survive with any two compartments flooded and not submerge the margin line (this is based on a hole 4.994m in length isn't going to cover more than 2 compartments - worse case if it occured right at the bulkhead between two).

                Final stage of flooding, just means the final condition that the ship would be in once it has fully flooded - it doesnt take into account the fact that the condition will be different during flooding until it reaches the "final stage".
                Magic, that makes sense. Just one final question if I haven't used up all of your patience. Below is from the damage requirements:

                3.2.2 The assumed extent of damage should be as follows:
                .1 longitudinal extent: vessels with the length (L) greater than 43 m, 3 m plus 3% of the vessel’s length. For those with length (L) not greater than 43 m, 10% of the vessel’s length,
                .2 transverse extent: transverse extent of damage should be assumed as 760 mm, measured inboard from the side of the vessel perpendicularly to the centreline at the level of the summer load waterline,
                .3 vertical extent: from the underside of the cargo deck, or the continuation thereof, for the full depth of the vessel.

                I've got .1 and .2 understood but .3, what do you make of that? This would mean a hole on the bottom?

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                • #9
                  I have no clue exactly what that means, I always understood it as being a hole from the keel to whatever deck would the first one above the water (ie - the top of the hole would still be above the waterline).
                  “Twenty years from now you will be more disappointed by the things you didn’t do than by the ones you did do. So throw off the bowlines, sail away from the safe harbor. Catch the trade winds in your sails. Explore. Dream. Discover.”

                  – Mark Twain
                  myBlog | @alistairuk | flickr | youtube Views and opinions expressed are those of myself and not representative of any employer or other associated party.

                  Comment


                  • #10
                    Originally posted by alistairuk View Post
                    I have no clue exactly what that means, I always understood it as being a hole from the keel to whatever deck would the first one above the water (ie - the top of the hole would still be above the waterline).
                    No worries, thanks very much for all your help! Greatly appreciated

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