Keel protection options

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  • 29th October 2011 at 10:01 pm #11149

      Hi, what do cats have for hull/keel protection if any? as l have just recently purchased an HT 27 with no keel protection and is currently being repaired as 2 areas have badly worn on the port hull keel bottom due to (we think) being in a tidal harbour prior to my purchase. My question is what do other cats have for keel protection, steel, wood, extra fibreglass, or something else?, my boat will be berthed in a tidal harbour in sandy mud which can be abrasive under certain weather conditions, l believe reading articles MK 1 HTs had wood bonded to the underside of the keels is this an option for later cats? or are other options available to me?
      On my last yacht (mono hull long keel) l fitted a stainless shoe for protection but this involved bolting through the hull to hold the shoe in place and would hope not to repeat this action, can anyone suggest tried and tested options that could be fitted to my boat, if only to give me piece of mind when on work rotation and not seeing the boat for weeks.

      Many thanks Garry

      HT27 Kellya

      31st October 2011 at 11:08 am #11958

        Hi Garry

        Wooden keel shoes are a common add-on option which can be done at any time. Bonded into place not bolted.

        One day I will get around to doing this on Allegro, it's on the jobs to do list. So I'm unable to give exact details.

        Mike
        Allegro III

        31st October 2011 at 2:48 pm #11959

          Yes Garry Mike is right most HTs and other cats simply cut plywood to the shape of the underside of the keel and bond it on with sikkaflex. There is no drilling through so if the whole thing should fall off (unlikely) then there is no damage, you are just back to the original build. If you want to be really clever you can fibreglass over the whole thing once it is in place and set..
          The alternative is to fabricate a fibreglass add on shoe and sikkaflex that on in the same manner. Wood is probably cheaper and easier, but the glass one might last longer.
          Regards
          Chrissie

          6th November 2011 at 11:27 am #11960

            An Ocean Winds I saw for sale had iron shoes.

            9th November 2011 at 8:07 pm #11961

              Hi, many thanks for the replies, some interesting ideas to think about, my original thought was ¾ oak cut to shape and bonded with polyester resin, but thinking of your suggestions above my new thinking may be to cut 5/8 birch plywood to shape and glass completely over with a few extra layers to the underside, they then could be bonded to the hulls with polyester resin, every spring they can be monitored for wear or damage and be repaired when the hulls are checked and anti-fowling applied.

              My experience with sikaflex as a bonding agent to hold materials in place when immersed underwater have been very poor, but yes agree it’s good for specific tasks.

              Dave steel or stainless shoes would be the preferred option but l`m very reluctant to fix these through the hull, unless other options may still be available.

              Garry

              10th November 2011 at 8:10 am #11962

                I was quoting the advert when I said “iron”..it could well have meant something tougher like s/s. Can't see why you couldn't use fixative to bond s/s to the keel. You would, I guess, not have to do the full length but only where it is likely to wear. Seems far less work and an almost permanent solution than your option: just thoughts.

                12th November 2011 at 4:48 pm #11963

                  Yes the thought had crossed my mind to fix 3mm stainless plate to the underside of both hulls but l have found without sides to make a shoe the stainless plate has no strength or elasticity, and as l tend to be moored in tidal harbours around the Firth of Forth examples are North Berwick and Inchkeith where rocks/stones can an issue when grounding, l `m hoping that plywood covered with fiberglass would give me a softer grounding on rocks and stones including some elasticity.

                  On another note l fitted a form of rubber strip to the full length of the keel on a Colvic Atlanta 29 a few years ago with sikaflex, never had any feedback due to the owner passing away, due to this the boat has never been moved or been out the water for years so the rubber and sikaflex may be holding ok, at the time of fitting l was led to believe this was normal practice for types of pleasure boats and yachts could this be an option for me or HTs?.

                  Garry

                  10th January 2012 at 12:25 am #11964

                    Gary, Mark Jarvis knows exactly how to fit keel shoes. I've watched him do it. Best ask him. If you can't, it's roughly like this: (1) use 2 inch thick hard wood NOT ply – the latter will not last (2) jack up boat (cradle supports were available at m/hull world) – only support at bulkeads – can tell where these are by tapping the hull (3) lay wood under keel, draw round shape (4) Cut out shape (5) Lightly criss cross the the top of the shoe – the bit that will bond to the keel – with 5 mm or so groves to allow better bond grip and some flex in the shoe (6) Cover with sikka (7) partially lover boat onto setting bond so as to keep a sikka bed of 5-10 mm thickness between shoe and keel – ie do not squich it all out of the join, so to speak. (8) trim off excess bead when set (9) Trim/sand/shape keel shoe – usually at the forward part so that it is hydro- dynamic (10) lower boat when cured, do the other side. I have seen s/steel shoes – expensive. Wood easiest. Don't drill any holes to hold anything through the keel – an an unnecessary risk and future maintenance hassle.

                    20th January 2012 at 9:04 pm #11957

                      Thanks Nick, l will probably for this year use birch or warkus ply as hull repairs are taking priority due to being rather extensive.
                      Future plans will defiantly be to fabricate and fit 3mm stainless steel shoes, this however may be a year or two down the line.
                      As l already have the port keel exposed due to rebuilding glass that’s worn away l will lift templates for the stainless shoes prior to fitting the plywood, this will allow me fabricate the shoes anytime and fitting the next time the boat may be out of the water hopefully at least few years.

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