Describe the various causes of any deterioration in the ship’s stability during the voyage. 1) The vessel is loading timber in tropical zone and in most cases the cargo will be in a dry state condition. 2) As the vessel progresses towards the destination in the loaded passage, she proceeds to the WNA area. 3) It is possible that the timber cargo may absorb more moisture which may increase the weight more than 15%. This reduces the GM and therefore GZ curve. 4) Free surface effect when fuel and water is consumed from the full tanks which reduced GM and therefore GZ curve. 5) Consumption of fuel, stores, FW during the passage will cause G to rise thereby reducing the GM and therefore GZ curve 6) During winter seasons, as the vessel moves towards higher latitude, will encounter series of depression resulting in bad weather. 7) Seas on deck will cause raise in G due to added weight and also cause FSE which reduces GM and GZ curve 8) Whilst experiencing heavy seas, if any of the lashing gives way and cargo break loose, it can result in catastrophic result due to deterioration of the stability of the vessel. 9) If the vessel is experiencing severe wind and spray on one side, it can result in unsymmetrical icing on deck and superstructure 10) As a result of this the vessel may list or loll over to due to increase in weight on one side. 11) This list or loss will reduce the vessel’s stability by way a) reduction in GMi b) produces heeling arm c) reduction in Area under the curve or the Dynamical stability d) Reduces the range of positive stability of the righting lever curve. e) Reduces the maximum righting lever. 12) If the vessel is lolled over, then the situation is further worsened. 13) This is because, if the vessel is experiencing severe weather and is lolled over then wind and wave motion will further heel the vessel.