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Hollow skeg revisited.

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  • g2rywjymyuxj4ldb4cqgt4agkbmsexonybeqvszq
    Hi all, Going back through the threads, I was reading about the time Oliver damaged his skeg on the slipway. On my boat there was no way to see the skeg from
    Message 1 of 17 , 1 Mar

      Hi all,

      Going back through the threads, I was reading about the time Oliver damaged his skeg on the slipway. On my boat there was no way to see the skeg from the inside as the bulkhead for the stern locker goes right down into the keel and inside the stern locker there is a piece of plywood glassed over the skeg to give the locker a flat bottom.

      Now when I bought the boat there was a lot of water inside from all the leaking deck fittings, but even after I had pumped her out and she was bone dry inside, I could still here water sloshing inside when I rocked her on the trailer. The only place it could be was in the skeg, so I drilled a small hole in the base of the stern locker and was able to suck out a couple of litres of fresh water (from tongue test) with an oil extractor. I then cut a hole in the plywood for a 4" inspection hatch so that I could mop it completely dry. 

      The puzzle is, how did fresh water get in there as she has been used in salt, secondly, as she has been sitting on a trailer for the last two years why didn't it leak out the way it came in?

      The real question I want to ask is this, I'm thinking of filling the hollow skeg under the stern locker with concrete. That will add a little bit of ballast, but also strengthen the skeg. 

      Is this a good idea or not?

      Regards, Tony.


    • olivershaw4229
      ... I quite like the idea, and initially it seems good, but I haven t fully thought it through. How will you actually get the concrete into the space,
      Message 2 of 17 , 1 Mar
        The real question I want to ask is this, I'm thinking of filling the hollow skeg under the stern locker with concrete. That will add a little bit of ballast, but also strengthen the skeg. 

        >  Is this a good idea or not?



        I quite like the idea,  and initially it seems good,  but I haven't fully thought it through.     How will you actually get the concrete into the space,  and be reasonably certain that the space is full?

        Certainly that hollow skeg is a vulnerability on the boat,  and I had further problems with my one last August,  at a different location and for a different reason.   To date I have concentrated on external reinforcement,  but if the informed consensus is that concrete filling the skeg is a good idea it would seem to add both modest strength and a significant impediment to flooding if the worst did happen and the skeg were damaged while afloat.



        Oliver

      • g2rywjymyuxj4ldb4cqgt4agkbmsexonybeqvszq
        Thanks Oliver. Getting the concrete in will be no problem because of the 4 inspection hatch I have fitted in the base of the stern locker. The space is quite
        Message 3 of 17 , 1 Mar
          Thanks Oliver.
          Getting the concrete in will be no problem because of the 4" inspection hatch I have fitted in the base of the stern locker. The space is quite small so ensuring it is completely filled should be okay. 
          I really wanted to run the idea past the group for any snags I hadn't thought of,  because once the concrete is in, it'll never come out again! 
        • Tony Glover
          Hi Tony With experience of larger yachts sailing offshore, the rule was to have access to all parts of the hull from the inside. One story I heard was a chap
          Message 4 of 17 , 1 Mar
            Hi Tony
            With experience of larger yachts sailing offshore, the rule was to have access to all parts of the hull from the inside.

            One story I heard was a chap anchored up, expecting to dry out on a mud bottom, ended up landing on an old groin spike.
            As the boat settled, the spike penetrated the hull. The hull filled with some water as the remaining tide ebbed. Once down, he pumped her out. He then used some bunk bases to construct a box around the spike, sealed it with mastic and waited, fingers crossed. Sure enough, as the tide rose, so did the boat and he managed to sail her back to harbour for a lift out and proper repair.

            Now, having seen how much space there is between the sole and bilge in a Privateer, I don't expect there to be much room for engineering projects of that type so filling it with concrete may well be a sensible option! 

            My only concern would be the constant slight movement of the hull against the concrete which could act like a grindstone. Perhaps add a protective layer between them?

            Interested to hear your decision.

            Regards
            Tony

            On 1 March 2017 at 22:25, tony08baker@... [privateer20] <privateer20@...> wrote:
             

            Thanks Oliver.

            Getting the concrete in will be no problem because of the 4" inspection hatch I have fitted in the base of the stern locker. The space is quite small so ensuring it is completely filled should be okay. 
            I really wanted to run the idea past the group for any snags I hadn't thought of,  because once the concrete is in, it'll never come out again! 


          • olivershaw4229
            Thank you for that insight. There is perhaps a complication, which has an impact on the bilge pumping arrangements. And at this point I realise that this is
            Message 5 of 17 , 1 Mar
              Thank you for that insight.

              There is perhaps a complication,  which has an impact on the bilge pumping arrangements.  

              And at this point I realise that this is an aspect of the construction of the boat that I have never fully examined.   I have of course many times seen inside the stern locker (lazarette),  as surely most of us have.   I have also of course many times seen the exterior of the skeg,  as again I am sure most of us have.   And I have on a number of occasions seen the space beneath the cockpit sole from inside the cabin,  as probably many of us have.   Additionally,  I have twice now experienced leaks when water has clearly entered the bottom of the skeg,  when the skeg has been damaged,  and the water has then travelled from there into the cabin area.   

              But what I have never done is to thoroughly examine that space beneath the cockpit sole for the purpose of examining the deepest parts of the skeg  -  and I suspect that here again many of us may be in the same situation.     So my knowledge of the construction is based on only those four separate sources,  put together,  but without the missing confirmation.  

              But on that basis it appears that the skeg is hollow throughout,  that the void is capped at the extreme after end by the floor of the lazarette,  and forward of that it is capped by the cockpit floor,  but that the space is fully open at the forward end.     At the after end the inside is a very deep recess,  which becomes quite shallow by the forward end of the cockpit.

              Into this recess,  at least on my boat,  fits the hose for the bilge pump,  with its strum box at the forward end.    There is just enough width for the particular strum box on my boat to rest on the bottom of the skeg/keel hollow.

              Whatever may be done,  it is vitally important that bilge pumping arrangements are not compromised.   This consideration includes the need to be able occasionally to remove and clean the strum box,  and perhaps occasionally  -  maybe only once or twice in the lifetime of the boat  -  to remove and replace the hose.    That does not necessarily rule out filling the skeg with concrete,  but it most certainly does mean that one needs to take care to ensure that the concrete does not obstruct inspection and replacement of these vital components.



              Oliver

            • g2rywjymyuxj4ldb4cqgt4agkbmsexonybeqvszq
              Hi Oliver, Just to clarify one point, if you are in the cabin and you look into the space under the cockpit sole, can you see all the way to the end of the
              Message 6 of 17 , 1 Mar
                Hi Oliver, 
                Just to clarify one point, if you are in the cabin and you look into the space under the cockpit sole, can you see all the way to the end of the skeg?
              • olivershaw4229
                That is what I don t know. The short answer is that it is certainly not easily visible; but if you look from very low down, and with the aid of a torch,
                Message 7 of 17 , 2 Mar
                  That is what I don't know.

                  The short answer is that it is certainly not easily visible;   but if you look from very low down,  and with the aid of a torch,  you might well then be able to see it.

                  This is what I have never put to the test.

                  And to attempt it now,  on my boat,  would entail first removing all the extra ballast that I added in 2014  ...   ...



                  Oliver

                • Jonathan Knight
                  Fresh water indicates a leak from above. Use of concrete sounds too much like a once in the life of the boat operation. If you damage the hull how would you
                  Message 8 of 17 , 2 Mar
                    Fresh water indicates a leak from above.
                    Use of concrete sounds too much like a 'once in the life of the boat' operation. If you damage the hull how would you work around the concrete, and how much damage might you do trying to get it out. 
                    It could be cast in sections but how much would that strengthen the boat?
                    It would defeat the designers concept that the rear balast was adjustable to allow for differing crew.
                    I find sausages of sand work well. Is it possible that slightly loose material will act a little like the proverbial snooker balls and transmit energy. The sausages of sand are easily got rid of for a long tow and easily dried out. 
                    The internal v of the skeg provides a good sump / low point for any loose water in the boat.
                    My bilge pump has a two way valve immediately below it so that I can set it to draw from the bottom inside of the skeg or directly from the cockpit floor. Touch wood that I never have to pump water from the skeg. To ensure that the sausages of sand do not affect the flow of water from anywhere in the boat to the skeg I have a 40mm waste pipe lying the length of the v of the skeg in the sole locker.
                    I don't know that the skeg is a general weakness, mine has taken quite a bit of thumping. So far as I know only Oliver has been unlucky in this regard. It is likely that the construction method is variable depending on age of boat, like a number of other design features. As stated in the brochure mine has the central balast bonded into the cabin floor and therefore shows no flex or weakness there.
                    Regards Jonathan

                    On 2 Mar 2017 08:12, "acapella13934@... [privateer20]" <privateer20@...> wrote:
                     

                    That is what I don't know.

                    The short answer is that it is certainly not easily visible;   but if you look from very low down,  and with the aid of a torch,  you might well then be able to see it.

                    This is what I have never put to the test.

                    And to attempt it now,  on my boat,  would entail first removing all the extra ballast that I added in 2014  ...   ...



                    Oliver

                  • g2rywjymyuxj4ldb4cqgt4agkbmsexonybeqvszq
                    OK, on my boat, if I m in the cabin and peer into the space beneath the cockpit sole, I cannot see right to the end of the skeg, because the bulkhead that
                    Message 9 of 17 , 2 Mar
                      OK, on my boat, if I'm in the cabin and peer into the space beneath the cockpit sole, I cannot see right to the end of the skeg, because the bulkhead that forms the stern locker, or lazarette, comes right down into the keel/skeg. Therefore, the very after end of the skeg underneath the lazarette is a completely enclosed and inaccessible space. (Or it was until I cut an inspection hatch in the base of the lazarette.) 
                      It is that small space under the lazarette that I fancy filling with concrete.
                    • Jonathan Knight
                      NoJust read Oliver message which must have just preceeded mine. Under my sole the glass fibre moulding cleanly follows the deepening v of the skeg as far as
                      Message 10 of 17 , 2 Mar
                        NoJust read Oliver message which must have just preceeded mine.
                        Under my sole the glass fibre moulding cleanly follows the deepening v of the skeg as far as the lazarette wall where it is sealed from the lazarette. There is no 'floor' just the shape of the hull.
                        My lazarette has a loose slatted floor easily removable. This allows me to see to the foot of the lazarette to check for water. I don't have any pumping arrangement for this space.
                        Just read your further message confirming that you are referring to the lazarette space only Peter and that just goes to show how variable the boats are.
                        Stick with bags of sand that you can get rid of.
                        Regards Jonathan


                        On 2 Mar 2017 08:00, "tony08baker@... [privateer20]" <privateer20@... > wrote:
                         

                        Hi Oliver, 

                        Just to clarify one point, if you are in the cabin and you look into the space under the cockpit sole, can you see all the way to the end of the skeg?
                      • Jonathan Knight
                        My last message comments on the wall of the lazarette. As regards fresh water in the lazarette, I find that when the boat is parked up on the trailer there
                        Message 11 of 17 , 2 Mar
                          My last message comments on the wall of the lazarette. 
                          As regards fresh water in the lazarette,  I find that when the boat is parked up on the trailer there only has to be a slight slope to the rear for rain  water to overflow the upstand of the lazarette locker under its lid and thus drain into the lazarette. I have contemplated sealing the lid. However as I keep spare fuel in the lazarette it needs to allow fumes to escape. If I did seal it then I would have to put a vent in the lid. I have not found it a big enough problem to do this.

                          Regards Jonathan

                          On 2 Mar 2017 08:54, "tony08baker@... [privateer20]" <privateer20@...> wrote:
                           

                          OK, on my boat, if I'm in the cabin and peer into the space beneath the cockpit sole, I cannot see right to the end of the skeg, because the bulkhead that forms the stern locker, or lazarette, comes right down into the keel/skeg. Therefore, the very after end of the skeg underneath the lazarette is a completely enclosed and inaccessible space. (Or it was until I cut an inspection hatch in the base of the lazarette.) 

                          It is that small space under the lazarette that I fancy filling with concrete.
                        • Tony Glover
                          Hi Jonathan. I m getting my boat ready for inspection by the Boat Safety Scheme chaps. I was planning have spare fuel and an LPG canister in the lazerette.
                          Message 12 of 17 , 2 Mar

                            Hi Jonathan.
                            I'm getting my boat ready for inspection by the Boat Safety Scheme chaps.
                            I was planning have spare fuel and an LPG canister in the lazerette. However, this is not allowed with BSS as petrol and gas vapours are heavier than air so the locker would need a drain hole in the very bottom (undetwater in my case!).
                            Perhaps a sealed false floor with a drain above waterline?
                            Regards Tony


                            On 2 Mar 2017 9:40 a.m., "Jonathan Knight jontsknight@... [privateer20]" <privateer20@...> wrote:
                             

                            My last message comments on the wall of the lazarette. 
                            As regards fresh water in the lazarette,  I find that when the boat is parked up on the trailer there only has to be a slight slope to the rear for rain  water to overflow the upstand of the lazarette locker under its lid and thus drain into the lazarette. I have contemplated sealing the lid. However as I keep spare fuel in the lazarette it needs to allow fumes to escape. If I did seal it then I would have to put a vent in the lid. I have not found it a big enough problem to do this.

                            Regards Jonathan

                            On 2 Mar 2017 08:54, "tony08baker@... [privateer20]" <privateer20@... > wrote:
                             

                            OK, on my boat, if I'm in the cabin and peer into the space beneath the cockpit sole, I cannot see right to the end of the skeg, because the bulkhead that forms the stern locker, or lazarette, comes right down into the keel/skeg. Therefore, the very after end of the skeg underneath the lazarette is a completely enclosed and inaccessible space. (Or it was until I cut an inspection hatch in the base of the lazarette.) 

                            It is that small space under the lazarette that I fancy filling with concrete.

                          • olivershaw4229
                            Perhaps better, get rid of the gas, and use an alcohol cooker. For an LPG system to be safe aboard a boat it needs to be a fully engineered marine quality
                            Message 13 of 17 , 2 Mar
                              Perhaps better,   get rid of the gas,  and use an alcohol cooker.   

                              For an LPG system to be safe aboard a boat it needs to be a fully engineered marine quality installation.   That will have a vented gas locker,  marine grade cooker (i.e. with marine grade taps),  manual and automatic (solenoid-operated) cutoff valves,  bilge blower,  and gas detector in the bilge (and suitably coupled to the cutoff valve and the bilge blower).  

                              An LPG system that meets that requirement is seriously expensive,  and difficult to install on such a small boat as the Privateer.   An alcohol stove is very much simpler,  easier to install,  and somewhat less expensive.

                              I am not sure about the stowage for the petrol,  though.    Since I don't normally use the inland waterways I don't get involved with the Boat Safety Scheme;   its remit does not extend to seagoing,  so I can store my petrol in the lazarette without compunction.    But a quick check on the private boat page of the BSS website seems to indicate that they are concerned about:
                              • LPG installations
                              • Gas or oil fuel for appliances
                              • Portable fuel tanks for inboard engines may not be placed inside the engine space/s
                              • Mains power
                              Crucially,  I see no mention there of outboard motors,  or their fuel.   This is not to say that it is not assessed,  nor that if it is assessed they would refuse to accept it in the lazarette;   merely that they don't seem to mention it so you would need to make further enquiries.



                              Oliver

                            • g2rywjymyuxj4ldb4cqgt4agkbmsexonybeqvszq
                              Hi Jonathan, The difference between our boats is that you have a loose slatted base in the lazarette whereas mine has a permanently bonded in piece of ply,
                              Message 14 of 17 , 2 Mar
                                Hi Jonathan, 
                                The difference between our boats is that you have a loose slatted base in the lazarette whereas mine has a permanently bonded in piece of ply, hence the confusion.
                                I do intend to use sandbags as necessary under the cockpit sole. 
                                Regards, Tony. 
                              • Jonathan Knight
                                Fortunately when I got my BSS this wasn t raised as an issue and the lazarette was considered fine for the 6 gallon petrol tank I have in it as the lazarette
                                Message 15 of 17 , 2 Mar
                                  Fortunately when I got my BSS this wasn't raised as an issue and the lazarette was considered fine for the 6 gallon petrol tank I have in it as the lazarette is external to the accommodation and is well vented through the lid. By the time it is filled with a tank that size there isn't a lot of room for fumes. At the time of the BSS I had a portable gas stove which is considered outside the scope of the certificate as are its small canisters. I have since, like Oliver, gone over to use a ridiculously expensive spirit stove, which is acceptable under the BSS.

                                  Regards Jonathan

                                  On 2 Mar 2017 10:34, "Tony Glover tonytheskipper@... [privateer20]" <privateer20@...> wrote:
                                   

                                  Hi Jonathan.
                                  I'm getting my boat ready for inspection by the Boat Safety Scheme chaps.
                                  I was planning have spare fuel and an LPG canister in the lazerette. However, this is not allowed with BSS as petrol and gas vapours are heavier than air so the locker would need a drain hole in the very bottom (undetwater in my case!).
                                  Perhaps a sealed false floor with a drain above waterline?
                                  Regards Tony


                                  On 2 Mar 2017 9:40 a.m., "Jonathan Knight jontsknight@... [privateer20]" <privateer20@... > wrote:
                                   

                                  My last message comments on the wall of the lazarette. 
                                  As regards fresh water in the lazarette,  I find that when the boat is parked up on the trailer there only has to be a slight slope to the rear for rain  water to overflow the upstand of the lazarette locker under its lid and thus drain into the lazarette. I have contemplated sealing the lid. However as I keep spare fuel in the lazarette it needs to allow fumes to escape. If I did seal it then I would have to put a vent in the lid. I have not found it a big enough problem to do this.

                                  Regards Jonathan

                                  On 2 Mar 2017 08:54, "tony08baker@... [privateer20]" <privateer20@... > wrote:
                                   

                                  OK, on my boat, if I'm in the cabin and peer into the space beneath the cockpit sole, I cannot see right to the end of the skeg, because the bulkhead that forms the stern locker, or lazarette, comes right down into the keel/skeg. Therefore, the very after end of the skeg underneath the lazarette is a completely enclosed and inaccessible space. (Or it was until I cut an inspection hatch in the base of the lazarette.) 

                                  It is that small space under the lazarette that I fancy filling with concrete.

                                • olivershaw4229
                                  ... I suppose I can see why that is outside the scope, for the simple reason that it could be removed from the boat for the inspection and carried aboard
                                  Message 16 of 17 , 2 Mar
                                    >  At the time of the BSS I had a portable gas stove which is considered outside the scope of the certificate as are its small canisters.


                                    I suppose I can see why that is outside the scope,  for the simple reason that it could be removed from the boat for the inspection and carried aboard later.    It would therefore be almost impossible to police it in practice if it were included in the scheme.

                                    But for what is arguably the most potentially lethal of all LPG stoves to fall outside the scope of the certificate simply makes a mockery of the entire system!




                                    Oliver

                                  • olivershaw4229
                                    ... And mine is different again; solid GRP, which looks to be original. However we know that there were a number of changes over the comparatively short
                                    Message 17 of 17 , 2 Mar
                                      > The difference between our boats is that you have a loose slatted base in the lazarette whereas mine has a permanently bonded in piece of ply, ...




                                      And mine is different again;  solid GRP,  which looks to be original.

                                      However we know that there were a number of changes over the comparatively short production run of the boats,  and my one is an early one;   early pattern drop keel,  and an empty bilge beneath the cabin sole (rather than ballast filling the space),  and a moulding number which appears to date her at 1974 (number 74  055).     Indeed if the sail number is to be believed it may just possibly be the first one,  but then sail numbers on boats that have had several owners are notoriously unreliable.  Nonetheless she came to me with number 1 on her sail and that has never been challenged,  and I have found no evidence of any earlier examples,  so I am sticking with that number!.



                                      Oliver
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