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Underwater Sealant

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  • olivershaw4229
    Decades ago, when I owned a 1912 wooden yacht, I used to regularly use a marvellous sealant; LifeCalk, by Boatlife. To summarise the manufacturer s
    Message 1 of 17 , Apr 17, 2016

      Decades ago,  when I owned a 1912 wooden yacht,  I used to regularly use a marvellous sealant;   LifeCalk,  by Boatlife.    To summarise the manufacturer's instructions:   preferably apply to clean dry surfaces,  but if necessary apply to damp surfaces;   in emergency can even be applied underwater.    My own addition to those instructions is to take care to ensure that it is not allowed to touch anything where it is not wanted,  because it sticks to almost anything,  voraciously.


      With a boat of the age of mine this was occasionally a life saver.


      I have long lamented its virtual disappearance from the UK market,  which I would guess is primarily because no-one now can be bothered to import it.   Amazon will supply it,  but at an astronomical price;   otherwise it is a matter of importing it from the USA.


      I was therefore delighted to receive an advertising email recently for this product,  which looks to be something comparable.   It may be of interest to others.    I stress that I have not seen it in the flesh,  much less had an opportunity to put it to the test,  so make your ownb judgements on it,  but I pass on the information in good faith.


      C.T.1 UNDERWATER MARINE SEALANT - C.T.1 Sealant - Discount Marine Chandlery and Sailing Equipment. Bargain Boat Spares and Clothing




      Oliver

    • olivershaw4229
      Decades ago, when I owned a 1912 wooden yacht, I used to regularly use a marvellous sealant; LifeCalk, by Boatlife. To summarise the manufacturer s
      Message 2 of 17 , Apr 17, 2016

        Decades ago,  when I owned a 1912 wooden yacht,  I used to regularly use a marvellous sealant;   LifeCalk,  by Boatlife.    To summarise the manufacturer's instructions:   preferably apply to clean dry surfaces,  but if necessary apply to damp surfaces;   in emergency can even be applied underwater.    My own addition to those instructions is to take care to ensure that it is not allowed to touch anything where it is not wanted,  because it sticks to almost anything,  voraciously.


        With a boat of the age of mine this was occasionally a life saver.


        I have long lamented its virtual disappearance from the UK market,  which I would guess is primarily because no-one now can be bothered to import it.   Amazon will supply it,  but at an astronomical price;   otherwise it is a matter of importing it from the USA.


        I was therefore delighted to receive an advertising email recently for this product,  which looks to be something comparable.   It may be of interest to others.    I stress that I have not seen it in the flesh,  much less had an opportunity to put it to the test,  so make your ownb judgements on it,  but I pass on the information in good faith.


        C.T.1 UNDERWATER MARINE SEALANT - C.T.1 Sealant - Discount Marine Chandlery and Sailing Equipment. Bargain Boat Spares and Clothing




        Oliver


      • olivershaw4229
        I gave the bilges a thorough wash today. Unintentionally ... ... In good Mersey water ... ... The intention was simply to launch the boat and put her
        Message 3 of 17 , Apr 22, 2016
          I gave the bilges a thorough wash today.

          Unintentionally   ...   ...

          In good Mersey water  ...   ...

          The intention was simply to launch the boat and put her out to anchor overnight.

          Our concrete slipway is almost horizontal,  so one has to wade the trailer deep.  The timing,  about an hour and a half after HW,  was determined by various circumstances,  but it was pre-planned for that time;  the only alternative was to delay until tomorrow.

          With a moderately strong ebb setting across the slip it is a matter of judgement,  and safety (not least safety of personnel),  how deep to wade the trailer;  the intention is the minimum which will enable to boat to be winched off into water just deep enough to float.    Too deep,  and it has been known for people to be swept off their feet by the tide.

          By now our "shore team" are getting almost professional.

          Unfortunately on this occasion we very slightly misjudged,  and lightly bashed the end of the skeg on the concrete as she came off the trailer.    The subsequent events were where I learned that:  (1)  the skeg is hollow,  (2) the GRP skin is thin,  and (2) the skeg communicates directly with the bilge  ..   ...

          Not realising the problem I put her out to anchor;   and then discovered water just lapping the cabin sole,  and advancing rapidly.    If one unexpectedly finds water above the cabin sole in a GRP boat,  which normally should not leak,  it is usually indicative of a serious and urgent problem,  never mind seeing the water level visibly increasing.

          Some urgent pumping followed,  interspersed with repeated attempts (eventually successful) to contact the sailing club to mobilise the shore team to bring tractor and trailer and an enhanced recovery team down the slip to recover her in what was by now a good 3 to 4 knots of ebb across the slip.

          We did the job,  and as the yacht was towed back up the slip we saw the water pouring out from the back of the skeg.

          Perhaps this was a blessing in disguise,  as I think from examining the damage that it had been damaged previously,  and this fairly slight bump was just the last straw.    Just as well to have it happen on my own doorstep,  and with a well practised shore team and the right recovery vehicle immediately to hand.

          Repair should be straigtforward,  but I am very tempted to start by inserting some mahogany into the aperture,  and bed that in place with polysulphide sealant.  Then once that is cured,  epoxy filler (probably International Paints' Water-Tite,  since I have that in stock already) to build up a flush surface.   Then several layers of woven glass rovings and epoxy laid up on the outside,  and extending well up the (properly prepared) outer surface of the skeg.

          Unless anyone has any better ideas  ...   ....

          All ideas welcome,  but I hope to start the job tomorrow morning,  Saturday.



          Oliver
        • aartvanderpol@rocketmail.com
          You were luckily unlucky! Any Pictures? The weather here in Groningen is too cold and wet for repairs. Hope you have higher temperatures. Aart
          Message 4 of 17 , Apr 23, 2016
            You were luckily unlucky!
            Any Pictures?
            The weather here in Groningen is too cold and wet for repairs.
            Hope you have higher temperatures.
            Aart
          • olivershaw4229
            UPDATE. I have now prepared the exterior of the hog for fibreglassing; removed the antifoul and ground down the GRP in a taper to enable me to scarf in new
            Message 5 of 17 , Apr 23, 2016
              UPDATE.

              I have now prepared the exterior of the hog for fibreglassing;   removed the antifoul and ground down the GRP in a taper to enable me to scarf in new epoxy/glass laminate.

              I have also inserted a piece of mahogany,  coated with epoxy on all surfaces,  into the cavity,  and insofar as limited access has permitted I have have attempted to bed this onto polysulphide mastic,  and secured it in place by screws.

              That is as far as I could get on day one,  because of the time needed for first the epoxy and then the polysulphide to cure.

              Tomorrow,  weather permitting,  I shall cut off the protruding timber and then start laminating up the new epoxy GRP on the exterior.    I hope and intend to complete the entire lamination,  wet on wet,  in the one session;   but working with epoxy it won't matter unduly if I have to split it into two or more sessions.

              Once that is done the repair can be regarded as sufficiently finished to permit the boat to be launched and used,  so I am still on track for my intended cruise departing on Thursday afternoon's tide,  weather permitting.     If I can get some paint on prior to launching that would be a bonus,  but if not that can await my return.

              After I return I intend to have a metal protective shoe fabricated.

              I am also toying with the idea of using some sort of foam,  injected through a tube as a liquid,  to fill the cavity.    I would be happy to drill one or more small diameter holes in the upper part of the skeg for this purpose,  as they can readily be filled later.

              Any recommendations for a suitable foaming product for this purpose?




              Oliver
            • olivershaw4229
              ... Drat!! It is always the same, with me at least: taking photos does not occur to me until the job is well underway. At outset I am too preoccupied
              Message 6 of 17 , Apr 23, 2016
                Any Pictures?




                Drat!!

                It is always the same,  with me at least:   taking photos does not occur to me until the job is well underway.    At outset I am too preoccupied with rescuing the boat (in this instance),  and then with getting on with the repair;   photos come to mind only when the back of the job is already broken.

                And on this occasion I even had the camera on board,  for other reasons.

                So no photos of the water gushing out,   or of the hole,  or of the mahogany insert.

                But I will try to remember to take some photos from here onwards   ...



                Oliver
              • Jonathan Knight
                Well done for sorting the problem so quickly. I m astonished that the skeg is hollow. I wonder if all the boats were built like that. I have always assumed
                Message 7 of 17 , Apr 24, 2016

                  Well done for sorting the problem so quickly. I'm astonished that the skeg is hollow. I wonder if all the boats were built like that. I have always assumed that that was one of the areas for the built in ballast, at least for those boats with built in ballast. I can't see any sensible way of checking.
                  I hope that the repair is proceeding alright today.
                  Jonathan

                  On 24 Apr 2016 01:20, "acapella13934@... [privateer20]" <privateer20@...> wrote:
                   

                  UPDATE.


                  I have now prepared the exterior of the hog for fibreglassing;   removed the antifoul and ground down the GRP in a taper to enable me to scarf in new epoxy/glass laminate.

                  I have also inserted a piece of mahogany,  coated with epoxy on all surfaces,  into the cavity,  and insofar as limited access has permitted I have have attempted to bed this onto polysulphide mastic,  and secured it in place by screws.

                  That is as far as I could get on day one,  because of the time needed for first the epoxy and then the polysulphide to cure.

                  Tomorrow,  weather permitting,  I shall cut off the protruding timber and then start laminating up the new epoxy GRP on the exterior.    I hope and intend to complete the entire lamination,  wet on wet,  in the one session;   but working with epoxy it won't matter unduly if I have to split it into two or more sessions.

                  Once that is done the repair can be regarded as sufficiently finished to permit the boat to be launched and used,  so I am still on track for my intended cruise departing on Thursday afternoon's tide,  weather permitting.     If I can get some paint on prior to launching that would be a bonus,  but if not that can await my return.

                  After I return I intend to have a metal protective shoe fabricated.

                  I am also toying with the idea of using some sort of foam,  injected through a tube as a liquid,  to fill the cavity.    I would be happy to drill one or more small diameter holes in the upper part of the skeg for this purpose,  as they can readily be filled later.

                  Any recommendations for a suitable foaming product for this purpose?




                  Oliver
                • rrob437
                  This is a big concern as mine dries out on shingle. I ll be looking more closely at this. Another concern then is the lack of internal bouyancy in the boat. i
                  Message 8 of 17 , Apr 28, 2016
                    This is a big concern as mine dries out on shingle. I'll be looking more closely at this.

                    Another concern then is the lack of internal bouyancy in the boat. i have tried to address this is some small way by purchasing large inflatable fenders (used as mooring fenders) from force 4 chandlery. They have been slide down either side of the quarter berths under the cockpit seats and should hopefully stop her from going down completely if holed!!
                  • olivershaw4229
                    ... The first, and minimum, protection needed for drying out on shingle is an adequate keelband. You may wish to beef up the GRP as well; if you do
                    Message 9 of 17 , Apr 29, 2016
                      >  This is a big concern as mine dries out on shingle. I'll be looking more closely at this.


                      The first,  and minimum,  protection needed for drying out on shingle is an adequate keelband.    You may wish to beef up the GRP as well;   if you do that,  be sure to use epoxy,  rather than polyester.    Polyester works fine at the layup stage,  when it is laminated "wet on wet",  but it does not adhere well to other materials,  not even to cured polyester.    Epoxy adheres vastly better,  and it is stronger,  and for that reason it has today become the standard resin for marine GRP work as well as the standard adhesive for marine woodwork.    Unfortunately it is also more expensive than polyester.

                      I am also considering infilling the hollow skeg with some form of foam,  injected in liquid form,  and starting to research materials for this.

                      For my situation,  where there is a small risk of banging the end of the skeg on the concrete when I winch the boat off her trailer,  I am also intending to have a stainless steel shoe fabricated,  as further protection;   and very probably also bond on a sacrificial bump stop (in either hard rubber or wood),  but that is very specific to my launching situation and would not be relevant to drying out on shingle.



                      Oliver



                    • olivershaw4229
                      ... This is a difficult question. I did try to reply to this part of the post, but then lost the lot just as I was putting the final touches to it. Don t
                      Message 10 of 17 , Apr 29, 2016
                        Another concern then is the lack of internal buoyancy in the boat. 



                        This is a difficult question.

                        I did try to reply to this part of the post,  but then lost the lot just as I was putting the final touches to it.    Don't you just love this technology!

                        Will try again,  but it won't be immediate.    Likely to be much later in the day,  or possibly some time over the weekend.



                        Oliver

                      • Aart van der Pol
                        Is it possible that there has been wood inside? It might have rotten away? Op 29 apr. 2016 10:32 schreef acapella13934@talktalk.net [privateer20]
                        Message 11 of 17 , Apr 29, 2016

                          Is it possible that there has been wood inside? It might have rotten away?

                          Op 29 apr. 2016 10:32 schreef "acapella13934@... [privateer20]" <privateer20@...> het volgende:
                           

                          >  This is a big concern as mine dries out on shingle. I'll be looking more closely at this.



                          The first,  and minimum,  protection needed for drying out on shingle is an adequate keelband.    You may wish to beef up the GRP as well;   if you do that,  be sure to use epoxy,  rather than polyester.    Polyester works fine at the layup stage,  when it is laminated "wet on wet",  but it does not adhere well to other materials,  not even to cured polyester.    Epoxy adheres vastly better,  and it is stronger,  and for that reason it has today become the standard resin for marine GRP work as well as the standard adhesive for marine woodwork.    Unfortunately it is also more expensive than polyester.

                          I am also considering infilling the hollow skeg with some form of foam,  injected in liquid form,  and starting to research materials for this.

                          For my situation,  where there is a small risk of banging the end of the skeg on the concrete when I winch the boat off her trailer,  I am also intending to have a stainless steel shoe fabricated,  as further protection;   and very probably also bond on a sacrificial bump stop (in either hard rubber or wood),  but that is very specific to my launching situation and would not be relevant to drying out on shingle.



                          Oliver



                        • olivershaw4229
                          ... Aart, That seems entirely possible, and I can neither confirm nor refute that. But if that is the case and if mine has rotted then so may a number of
                          Message 12 of 17 , Apr 29, 2016

                            Is it possible that there has been wood inside? It might have rotten away?



                            Aart,


                            That seems entirely possible,  and I can neither confirm nor refute that.   But if that is the case and if mine has rotted then so may a number of others.    


                            All I can say with certainty is that 42 years after the boat was built my one is now hollow.


                            It would be sensible for other owners to assume that their skegs may well be hollow,  for whatever reason,  and to be aware of this potential vulnerability.   Any sign of damage to the GRP should be regarded as potentially serious,  and not superficial,  and it should therefore be repaired ASAP.





                            Oliver

                          • olivershaw4229
                            ... It is perhaps a blessing in disguise that I lost my initial post. This is a very difficult question, with a lot of pros and cons; and if reserve
                            Message 13 of 17 , Apr 29, 2016
                              Another concern then is the lack of internal buoyancy in the boat. 

                              > This is a difficult question.

                              > I did try to reply to this part of the post,  but then lost the lot just as I was putting the final touches to it.    Don't you just love this technology!



                              It is perhaps a blessing in disguise that I lost my initial post.

                              This is a very difficult question,  with a lot of pros and cons;   and if reserve buoyancy is to be installed at all then the volume needed is so substantial that it very seriously interferes with stowage accommodation and also with space in the cabin.    There is no half-way house;  either the boat is going to remain afloat even if flooded,  or she is going to sink if flooded.   Unless you install sufficient to fully do the job (i.e. keep the boat afloat) there is no point in installing any at all;   the boat cannot "part float" if you have insufficient reserve buoyancy.

                              The Shipmates are our slightly smaller sister ships.    I am aware that some Shipmate owners have installed reserve buoyancy,  although I don't know of any who have actually conducted a swamp test,  while other Shipmate owners have deliberately decided not to go down that route.   There is no right or wrong answer to the yes/no decision;  what is right for one owner with one type of use of the boat may not be right for another.

                              I have now written a paper on this,  which I have uploaded to the Files section.   This document does not claim to be fully prescriptive,  and if other owners have useful additional knowledge or ideas please share them;    I would be entirely happy to incorporate them into a revised version of the document.



                              Oliver

                            • olivershaw4229
                              ... Might be helpful to point members in the right direction. Files Permanent Reserve Buoyancy.docx Oliver
                              Message 14 of 17 , Apr 29, 2016
                                I have now written a paper on this,  which I have uploaded to the Files section. 


                                Might be helpful to point members in the right direction.   Files > Permanent Reserve Buoyancy.docx





                                Oliver
                                 
                              • g8jmb
                                Oliver thanks for the paper on reserve buoyancy; excellent. And very applicable to the Shipmate. On which the lack of +ve buoyancy is a significant concer,n,
                                Message 15 of 17 , May 1, 2016

                                  Oliver

                                  thanks for the paper on reserve buoyancy; excellent. And very applicable to the Shipmate.  On which the lack of +ve buoyancy is a significant concer,n, despite SNBF approval.  I think there are some words somewhere on +ve buoyancy for the Shipmate - I'll see if I can find them.


                                  I would make the following suggestions:

                                  1 When calculating reserve buoyancy needed this may be reduced by the volume of the hull moulding below water {difficult to estimate, but if you ignore it that is a margin of safety]

                                  2.Similarly, allow for the volume of stores, etc EG, 100l of water + alcohol in plastic containers will effectively have neutral buoyancy and may be ignored.  Same goes for fuel

                                  3, A liferaft on deck will worsen stability

                                  4. Fit a downhaul on the cenreplate - but be careful, or build in some give, if you play touch and go.

                                  5 Access to the skeg - and keel void if it's like the Shipmate - cut a hole on the cockpit floor.  More easily closed and less worry than a hole below thw waterline.



                                  . In Poole YC we have a local racing class - the R19 - which has a cabin and heavy swing keel, 19ft x 8ft,weighs about 3/4 ton. Stability not probably dissimilar to the Privateer - can be capsized if you try hard enough - and people who should know better have done- and will then sink.. To sort this:

                                     a. keel lockdown with ~1ft movement possible [Poole is shallow]

                                     b.  approx. 1/2 m3 expanded polystyrene added at the aft end of the 1/4 berths

                                     c. very large inflatable buoyancy bag strapped in the bows. Later boats had foam under a V berth

                                  b and c coupled with hull skin buoyancy will ensure that she floats...the hull is grp/balsa sandwich, which helps

                                    d. positive fixing for the cabin hatch  - usually straps

                                   e self draining cockpit



                                  Cheers

                                  JohnB

                                • olivershaw4229
                                  Some good points there. Will incorporate into the next version of the paper. Oliver
                                  Message 16 of 17 , May 2, 2016
                                    Some good points there.    Will incorporate into the next version of the paper.



                                    Oliver

                                  • olivershaw4229
                                    Original version (v.1) now replaced with slightly revised version (v. 1.1) which incorporates John s suggestions plus a few other edits. Oliver
                                    Message 17 of 17 , May 2, 2016
                                      Original version (v.1) now replaced with slightly revised version (v. 1.1) which incorporates John's suggestions plus a few other edits.


                                      Oliver
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