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flooding problems

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  • Len Wingfield
    After capsizing and righting my ancient Gull I found she was flooded above the centreboard slot, whereas in practice capsizes she had always floated with water
    Message 1 of 11 , 3 Sep
      After capsizing and righting my ancient Gull I found she was flooded above the centreboard slot, whereas in practice capsizes she had always floated with water below the slot so that she could be bailed or sailed flooded. I tried tilting the boat to clear the extra water but couldnt heel her far enough. Remarkably a ‘strongbody’ came to my aid and was able to bail her fast enough to clear the centreboard slot.
       
      Any ideas please on the reason for flooding so deep? (No,  the fore and aft buoyancy compartments were clear, and the added polystyrene foam side buoyancy was also intact.) The hollow skeg had broken open, but this only amounts to less than 40 square inches of buoyancy.
       
      I had always thought that the CB slot had to be sealed for deep bailing. My slot has no flap-seals below. Possibly it had become sealed with clay on the mudbank but I dont think so.
       
      cheers Len
    • Steve White
      Len, It’s known that when the sea is above the level of the centreboard on dinghies one has to stuff the centreboard case with whatever is to hand in order
      Message 2 of 11 , 3 Sep
        Len,

        It’s known that when the sea is above the level of the centreboard on dinghies one has to stuff the centreboard case with whatever is to hand in order to effectively bail. That can be the sailbag, a jumper, anything to stop the upwelling of water. The centreboard gasket seal is rarely good enough to stop the upwelling of water. 

        The polystyrene or sealed floatation within a hull (not a buoyancy tank, but a sealed compartment within the buoyancy tank, or polystyrene blocks within the buoyancy tank) will only guarantee that the dinghy won’t actually completely sink.

        How much water comes into the hull at the point of righting a dinghy depends on many factors, including the buoyancy location in the hull, the wind, how much you are weighing the hull down, how much is already in it and so on. If you have a crew (I know you didn’t) they can sometimes do a very effective job of keeping water out of the boat by acting as a dam just as the mast rises, and they are rolled into the boat leaving the water outside. 

        (I’m sorry that I didn’t make it to camp this year - the last weekend was my only opportunity and it was not forecast windy enough for a brisk round-Hayling, so I repaired things instead).

        Yours,

        Steve.

      • sail_and_oar
        My racing Ent was dreadful in this case. The side bouyancy was marginal at best and if the crew pushed down when righting the boat it would ship a lot of water
        Message 3 of 11 , 3 Sep
          My racing Ent was dreadful in this case. The side bouyancy was marginal at best and if the crew pushed down when righting the boat it would ship a lot of water as it came up. Climbing onto the centreboard was a sure way to end up bailing out about half a ton of water. I used to pull it back up with the jib sheet, easing the tension as the gunwale cleared the water. Later I added more bouyancy and it was a lot drier. 

          The Mirror is the opposite. It comes up nearly dry and any bilge water stays in the centre of the boat so it doesn't affect stability too much. The downside is these boats invert very readily and rig damage is a very real possibility. The answer is to jump out as soon as the point of no return is reached and quickly swim round to the centreboard to steady the boat. If you attempt to climb on the centreboard (especially a plywood one) it will probably break as it is only half an inch thick. 

          In 1960 Ian Proctor proved it is possible to design a boat which won't readily invert, comes up dry and has perfectly good performance when he brought us the Bosun. Despite being very strong, readily available, reasonably cheap, sea kindly and plastic this boat never really caught on with the DCA. I think Alan Earl had one for a time.

          Cliff


          ---In dinghysolent@..., <len@...> wrote :

          After capsizing and righting my ancient Gull I found she was flooded above the centreboard slot, whereas in practice capsizes she had always floated with water below the slot so that she could be bailed or sailed flooded. I tried tilting the boat to clear the extra water but couldnt heel her far enough. Remarkably a ‘strongbody’ came to my aid and was able to bail her fast enough to clear the centreboard slot.
           
          Any ideas please on the reason for flooding so deep? (No,  the fore and aft buoyancy compartments were clear, and the added polystyrene foam side buoyancy was also intact.) The hollow skeg had broken open, but this only amounts to less than 40 square inches of buoyancy.
           
          I had always thought that the CB slot had to be sealed for deep bailing. My slot has no flap-seals below. Possibly it had become sealed with clay on the mudbank but I dont think so.
           
          cheers Len
        • Len Wingfield
          A good point Cliff, I really need to check it with another practice capsize. Regarding the Bosun, I managed an inversion capsize in mine by a gust in light
          Message 4 of 11 , 4 Sep
            A good point  Cliff, I really need to check it with another practice capsize. Regarding the Bosun, I managed an inversion capsize in mine by a gust in light airs! Apart from racing I have never capsized in heavy winds. Len
             
            Sent: Sunday, September 3, 2017 9:30 PM
            Subject: [dinghysolent] Re:: flooding problems
             
             

            My racing Ent was dreadful in this case. The side bouyancy was marginal at best and if the crew pushed down when righting the boat it would ship a lot of water as it came up. Climbing onto the centreboard was a sure way to end up bailing out about half a ton of water. I used to pull it back up with the jib sheet, easing the tension as the gunwale cleared the water. Later I added more bouyancy and it was a lot drier. 

             
            The Mirror is the opposite. It comes up nearly dry and any bilge water stays in the centre of the boat so it doesn't affect stability too much. The downside is these boats invert very readily and rig damage is a very real possibility. The answer is to jump out as soon as the point of no return is reached and quickly swim round to the centreboard to steady the boat. If you attempt to climb on the centreboard (especially a plywood one) it will probably break as it is only half an inch thick. 
             
            In 1960 Ian Proctor proved it is possible to design a boat which won't readily invert, comes up dry and has perfectly good performance when he brought us the Bosun. Despite being very strong, readily available, reasonably cheap, sea kindly and plastic this boat never really caught on with the DCA. I think Alan Earl had one for a time.
             
            Cliff


            ---In dinghysolent@..., <len@...> wrote :

            After capsizing and righting my ancient Gull I found she was flooded above the centreboard slot, whereas in practice capsizes she had always floated with water below the slot so that she could be bailed or sailed flooded. I tried tilting the boat to clear the extra water but couldnt heel her far enough. Remarkably a ‘strongbody’ came to my aid and was able to bail her fast enough to clear the centreboard slot.
             
            Any ideas please on the reason for flooding so deep? (No,  the fore and aft buoyancy compartments were clear, and the added polystyrene foam side buoyancy was also intact.) The hollow skeg had broken open, but this only amounts to less than 40 square inches of buoyancy.
             
            I had always thought that the CB slot had to be sealed for deep bailing. My slot has no flap-seals below. Possibly it had become sealed with clay on the mudbank but I dont think so.
             
            cheers Len
          • Len Wingfield
            Many thanks Steve From: Steve White steve@zap.demon.co.uk [dinghysolent] Sent: Sunday, September 3, 2017 6:14 PM To: Subject:
            Message 5 of 11 , 4 Sep
              Many thanks Steve
               
              Sent: Sunday, September 3, 2017 6:14 PM
              Subject: Re: [dinghysolent] flooding problems
               
               

              Len,


              It’s known that when the sea is above the level of the centreboard on dinghies one has to stuff the centreboard case with whatever is to hand in order to effectively bail. That can be the sailbag, a jumper, anything to stop the upwelling of water. The centreboard gasket seal is rarely good enough to stop the upwelling of water.

              The polystyrene or sealed floatation within a hull (not a buoyancy tank, but a sealed compartment within the buoyancy tank, or polystyrene blocks within the buoyancy tank) will only guarantee that the dinghy won’t actually completely sink.

              How much water comes into the hull at the point of righting a dinghy depends on many factors, including the buoyancy location in the hull, the wind, how much you are weighing the hull down, how much is already in it and so on. If you have a crew (I know you didn’t) they can sometimes do a very effective job of keeping water out of the boat by acting as a dam just as the mast rises, and they are rolled into the boat leaving the water outside.

              (I’m sorry that I didn’t make it to camp this year - the last weekend was my only opportunity and it was not forecast windy enough for a brisk round-Hayling, so I repaired things instead).

              Yours,

              Steve.

            • Stephen White
              In my opinion the success or otherwise of a sailing dinghy is part marine architecture and part promotional pushing of the manufacturer. I sailed Bosuns from
              Message 6 of 11 , 4 Sep
                In my opinion the success or otherwise of a sailing dinghy is part marine architecture and part promotional pushing of the manufacturer.

                I sailed Bosuns from age 11 to 22, racking up about 40 sailing days a year in them, and I absolutely love them. In my opinion the marine architect got the design absolutely spot on. The Achilles heel is the weight of the hull. They are GRP right through, with no weight saving in the construction, and the GRP is thick and heavy.

                If a builder made a Bosun using modern materials in the hull, and refined the bracing my guess is that it would be half the weight and just as stiff.

                Changing the subject abruptly, I've bought a Comet Trio and one of the things I hope to sort it out for is overnight camping. Since I've not yet been to an overnight camp I've not seen how you've sorted out your boats for overnight camping (chicken and egg).

                Which resources on the internet do you rate as good to help a daysailer get into overnight camping? I'm very happy to learn, but I don't want to make a complete hash of it first time out.

                Thanks,

                Steve.
              • curlew5878
                I have a Secumar Buoyancy Cushion on the Mirror mast which I hope will inflate quickly enough to avoid inversion. When I capsized the boat in shallow water as
                Message 7 of 11 , 5 Sep
                  I have a Secumar Buoyancy Cushion on the Mirror mast which I hope will inflate quickly enough to avoid inversion. When I capsized the boat in shallow water as a trial, it needed only something like a litre of buoyancy on the mast to prevent inversion. But in rough weather it might need more, and the Secumar is 20 litres. It might also need more once it starts to invert, as the lever arm gets less.
                  I also know of someone using a little Rule bilge pump after a Mirror capsize, which removes 360 gallons per hour, which is still slow for the task, but is helpful.
                  David
                • paulh_boats
                  David, Regarding pumps I ve been experimenting with a 750 gallons per hour pump on MilliBee. It sits in the rear corner of the cockpit well for easy cleaning.
                  Message 8 of 11 , 5 Sep
                    David,

                    Regarding pumps I've been experimenting with a 750 gallons per hour pump on MilliBee.

                    It sits in the rear corner of the cockpit well for easy cleaning. The 1 inch pipe curves up into a side locker, through to the rear locker and out through a skin fitting on the transom.

                    Being a relatively dry boat the major use is after heavy rain that drains into the cockpit well.
                    I was amazed when first switched on. The water shot 2 feet out the rear, like a strong garden hose pipe. Regardless of battery life it wìll be a great bonus, it drains the cockpit about 10 times faster than myself.

                    There is a built in automatic float switch. To make that work well I'll have to cut a 20mm deep sump around the pump, so it only turns off when the flat cockpit sole has drained completely.

                    Many will rightly question electrics on a small boat. But regardless it could offer precious time to keep sailing if a big wave hits.

                    Even if the leisure battery runs flat, it is stiil useful ballast low down at the bow!

                    Paul
                  • curlew5878
                    Thank you Paul, I agree the pumps are really excellent and a great luxury. The water comes out with such a recoil, I could not secure the hose over the side
                    Message 9 of 11 , 6 Sep
                      Thank you Paul, I agree the pumps are really excellent and a great luxury. The water comes out with such a recoil, I could not secure the hose over the side using just a rope, but it needed a proper skin fitting. The 360gph pump can work from dry batteries if wanted. My 2 A-h re-chargeable battery has never run down, even sailing for hours in rough weather and pumping every minute or so.
                      david
                    • Len Wingfield
                      But do these pumps work when immersed? ( Incidentally my ‘waterproof’ phone pouch leaked although only briefly immersed! Len From: curlew5878@yahoo.co.uk
                      Message 10 of 11 , 7 Sep
                        But do these pumps work when immersed? ( Incidentally my ‘waterproof’ phone pouch leaked although only briefly immersed! Len
                         
                        Sent: Wednesday, September 6, 2017 9:19 PM
                        Subject: [dinghysolent] Re:: flooding problems
                         
                         

                        Thank you Paul, I agree the pumps are really excellent and a great luxury. The water comes out with such a recoil, I could not secure the hose over the side using just a rope, but it needed a proper skin fitting. The 360gph pump can work from dry batteries if wanted. My 2 A-h re-chargeable battery has never run down, even sailing for hours in rough weather and pumping every minute or so.
                        david

                      • curlew5878
                        Yes, they are designed to operate immersed. Even with a flooded battery box they will continue to work. David
                        Message 11 of 11 , 7 Sep
                          Yes, they are designed to operate immersed. Even with a flooded battery box they will continue to work.
                          David
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