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      Help! whats the difference between a yacht that has an AVS OF 135 and the downflooding angle of 122.3 ??? its the same yacht, i thought these figures should be the same, any ideas?

      i thought AVS 135 on a fin keeled 34ft yacht was impressive, do you? But downflooding angle of 122.3 worries me, should it?

      rgds Ray


        I say this very much with tongue in cheek: if you’ve got your yacht over at that sort of angle then you’ve probably got more important things to worry about than the angular difference between AVS and downflood. Perhaps reefing a bit earlier…

        Ian Culley
        Another Fantasy


          In the round a good question….
          The difference in the AVS and the down Flooding angle is due to the addition of the ingress of water into the vessel (Down Flooding) which in turn reduces the angle at which the vessel loses stability.

          Quote Wikipedia;
          If a ship floods, the loss of stability is caused by the increase in the centre of buoyancy, and the loss of waterplane area – thus a loss of the waterplane moment of inertia – which decreases the metacentric height. This additional mass will also reduce freeboard (distance from water to the deck) and the ship’s angle of down flooding (minimum angle of heel at which water will be able to flow into the hull). The range of positive stability will be reduced to the angle of down flooding resulting in a reduced righting lever. When the vessel is inclined, the fluid in the flooded volume will move to the lower side, shifting its centre of gravity toward the list, further extending the heeling force. This is known as the free surface effect.

          So – it you really need those extra 12.7 degrees, better make sure that the hatches and everything else are battened down and that no water can get below!


            Thanks CASAM, that explained it very well. Having spoken to a yachtmaster instructor, before reading this reply, he knows his stuff as well. Nice to get answers that actually help.

            thanks again



              Of interest to post 2006 37 owners. The fin keel is actually heavier than stated in the sales brochure. The brochure says 2000kg. Its actually 2130kg. I’ve a drwaing of the keel. Wonder why they did not promote the heavier keel giving better stability. Same keel as the later 38? With all the tinned food in the bilge it may account for the good seakeeping and windward ability we have found in gales.

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