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  • #6899
    Webmaster
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      Hi I am looking at re-propping CaSam.
      Her factory fit Volvo D120 saildrive is currently coupled to a fixed 2 blader.

      In an ideal world I am looking for something that is a quick and easy job (in slings) that will also imrpove performance under motor and sail without any remarkable downside in close quarters handling.

      All ideas welcome!
      Steve

      #9757
      Webmaster
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        Steve

        To me it’s a ‘no-brainer’….Brunton’s 2-blade feathering prop. Expensive but well worth the money: same boat speed at 500rpm less under power, between 0.5 and 0.75 kts extra under sail. Simple to fit.

        Ian Culley
        B32 Another Fantasy

        #9758
        Webmaster
        Participant

          Steve
          As Ian says the Bruntons Autoprop is a very good but expensive prop.
          Alternatives are the Bruntons Varifold, Flexofold and Volvo. All are standard folding props that are a bit cheaper than the Autoprop however Volvo seem to have stopped making folding props for the older sail drive legs such as the MS25.
          Over the years I have had 2 blade folding props from each manufacturer all on sail drives and found the Flexofold to be the best by far under power and sail than the Bruntons and Volvo.
          On anything less than 38 foot I would not waste the additional cost on a 3 blade prop as long as you get the right diameter and pitch.
          Regards
          Rick

          #9760
          Webmaster
          Participant

            Thanks Ian and Rick… I was looking at the Flexofold too, interesting given your view.

            #9761
            Webmaster
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              Has anyone tried the Volvo folder?
              The test results look good as the technology has been backwardly engineered from the IPS system.

              #9763
              Webmaster
              Participant

                I’ve got the 3 blade Volvo folder on my 2009 B31 Cruiser. Probably too much prop for my 18 hp.D1-20 but I love it! Lots of power, backs up great, and virtually no prop walk. Blades fold and spin up instantly. Only issue is you need to live with burning through the 3 part collar zincs quickly (threads elsewhere on this forum about them). I have to replace mine every 6 months, but my marina seems particularly bad for stray current…

                Good luck with your deliberations and let us all know what you decide on.

                Riyad
                s/v Battuta
                Vancouver, Canada

                #9764
                Webmaster
                Participant

                  So, I went to move CaSam to get her lifted and the new prop fitted…..only to find that I had no drive at all….
                  A short tow and the help of the very helpful guys at Sea Lift 2 at Haslar (not to mention a wallet full of ££’s!) and hey presto!

                  [attachment=3:casb2jic]2015-03-27 15.53.18.jpg[/attachment:casb2jic]
                  [attachment=2:casb2jic]2015-03-27 16.13.03.jpg[/attachment:casb2jic]
                  [attachment=1:casb2jic]2015-03-27 17.07.14.jpg[/attachment:casb2jic]
                  [attachment=0:casb2jic]2015-03-27 17.07.19.jpg[/attachment:casb2jic]

                  I’ll let you know how she gets on through the season.
                  Steve

                  #9774
                  Webmaster
                  Participant

                    Interesting thoughts and opinions.
                    I can only speak from my own experience. On Renovatio our 2003 B32. (Originally fitted with the standard 2 blade standard prop), we went for the Brunton two blade. With the Volvo prop we had a lot of prop-wash, but she made about 5.5Knts under power. Punching in to a headwind, even motor sailing the COG could slow to 2.5Knts.
                    After fitting the Bunton and with a clean bottom we could make 6.8Knts under power (COG). Punching in to tide and wind we never dropped below 5.5Knts, unless the sea state demanded that we ease back on the power.
                    Generally we got much better speeds under sail or motor sailing than using the 2 blade Volvo prop. The increased average passage speed allowed us to improve our cruising range. In a typical 10 hour day we could extend our passage plan by 12 to 15 miles. This made a big difference in the tide to tide port distance. Add to this the tidal drift it really made a difference.
                    As for economy, I am sure it made a big difference but, I have to say I never did the math.
                    On the down side;
                    The Brunton anode only lasted about 6 months, 9 at a stretch. But drying out against piles at regular intervals and checking with an underwater camera on a pole was not a big issue.
                    In summary ;
                    If I had kept Renevatio, I had planned to make a custom anode and back plate where the small M6 fixing screws were redundant and a 75% bigger anode with a central fixing would have extended the anode life. Our intension is to change the prop onImpavidus (and fit a new rope cutter) to the 3 blade Brunton (and Ambassador marine 3 blade cutter) in mid July before we set off on our summer cruise west. If we get the same results from the Brunton 3 blade, the expenditure will out way the cost. Not purely cost effectively admittedly. The increased performance and lack of prop wash is well worth it. You pays your money and makes your choice?
                    Note;
                    The Brunton is a torque/speed sensing prop, in close quarters you need to feed in a bit more throttle to stop, or change direction, it takes a second or two for the full power to take effect. Once it bites the power is delivered more effectively. As so, your crash speed is improved but, you need to give more power, but the boat will stop quicker!
                    I have not tested other props, so I can only speak from experience. A close friend who used to run a sailing school had a bad experience with a plastic bladed feathering prop. I can’t recall the name other than he told me it was supplied with a spare blade as standard!!!!!!!
                    Hope this is of use.
                    Best regards.
                    Ant and Cid.

                    #9776
                    Webmaster
                    Participant

                      I think that the plastic bladed folder is a “Kiwi Prop”.
                      I believe that Bill has one on Blaue Maus and he seems happy with it.
                      Bill any thoughts?

                      Steve

                      #9812
                      Webmaster
                      Participant

                        We have had a Kiwi prop on April Folly for several years. It’s a massive improvement on the standard 2 blade Volvo and hasn’t given us any problem at all. The performance is up by at least one knot under engine or sail and no anode issues. Also, the boat is very much easier to handle going astern. As with most props of this type, you do need to “wind it up” when changing from forward to astern or vice versa but this is very quick. I’ve never heard of blades becoming detached or broken.

                        David.

                        #9819
                        Webmaster
                        Participant

                          Coming back from the West Country over the last few days, CaSam has started to “judder” when put into reverse to stop her on a berth.
                          I had not experienced this at all to date…..any thoughts as to why this has just started?

                          On a side note. going into reverse from staitionary is not a problem, it appears to be worst when the boat is still moving forward?
                          Is it cavitation or somthing or simply the blades not “unfolding” properly for some reason? (and no I do not race in and “crash stop”)

                          Steve

                          #9821
                          Webmaster
                          Participant

                            @CaSam wrote:

                            Coming back from the West Country over the last few days, CaSam has started to “judder” when put into reverse to stop her on a berth.
                            I had not experienced this at all to date…..any thoughts as to why this has just started?

                            On a side note. going into reverse from staitionary is not a problem, it appears to be worst when the boat is still moving forward?
                            Is it cavitation or somthing or simply the blades not “unfolding” properly for some reason? (and no I do not race in and “crash stop”)

                            Steve

                            Sounds like the prop is not opening fully? I have an underwater B&W camera you can put on a pole to view your prop on a small screen, if its of any use?
                            Just bought a new Brunton 2 blade and a set of strippers for Impavidus, may be able to fit them befor the August bank holiday 🙂
                            Best regards

                            Ant.

                            #9822
                            Webmaster
                            Participant

                              Hi folks. We have fitted a Brunton Autoprop this last weekend. We also fitted Ambassador marines stripper rope cutter. I will do an article as I did for the MV heating system. However, for the moment as a teaser, top speed improvement of 1.25knts. No prop-wash. .75-1 knt @ at 1750 rpm.
                              Speed trials under sail yet to do. But, we are expecting similar improvement over the fixed Volvo prop.
                              BTW we have found the source of the vibration under power that we have had since delivery. The Volvo prop centre boss was found to be 1.5mm out of alignment!!!

                              For some reason I cannot upload pictures.

                              I will update when I figure it out 🙂

                              Best regards.

                              Ant & Cid

                              #9830
                              Webmaster
                              Participant

                                After diving under CaSam at the weekend I found the problem to the new and harsh vibration!
                                A ball of weed had trapped around the forward centre edge of the prop stopping the blades opening fully as was expected.
                                All clear now and power back to normal with zero vibrations!

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