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Re: Denison Deri Hydraulic motor reduction ratio

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  • svlevity
    Simon, We also have the Denison hydraulic drive and decided to buy a J Prop when we replaced ours. The J Prop is adjustable very quickly and easily under
    Message 1 of 13 , Aug 3, 2009
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      Simon,

      We also have the Denison hydraulic drive and decided to buy a J Prop
      when we replaced ours. The J Prop is adjustable very quickly and easily
      under water, only takes 15-30 seconds. The person we spoke to at J Prop
      was the only one who seemed to truly understand the issue of reduction
      ratio relative to the hydraulic drive system. After having determined
      the diameter of the prop you are going to get, the easy adjustability of
      the J Prop makes the most sense. There was no need to modify the
      propshaft because the folks at J Prop will machine the prop-taper to fit
      your shaft. We're very happy with the J Prop.

      Steve Perry
      CN 80 Levity



      --- In campernicholson@yahoogroups.com, Simon Frost <sfrost35@...> wrote:
      >
      > I am contemplating getting a feathering prop in the winter but need to know the reduction ratio for the Denison Deri M6-1 motor that runs off the original Perkins 4108. The Denison people based in Wakefield could not help as the motor is now extinct!
      >
      > Any thoughts and if so what feathering prop would be the best as it would need to exit straight out the back of the keel ie no P or A bracket fitted hence the reason that we struggle going astern! Currently we have the original 16'' x 8.5'' 2 bladed prop.
      >
      > Ideally a limited modification to the propshaft (1'' 1/8th diam) would be good
      >
      > Simon
      >
      > Samiotissa/62
      >
    • Simon Frost
      Thanks Steve for this although J Prop doesn t appear to have a UK agent which would be ideal. simon ... From: svlevity Subject:
      Message 2 of 13 , Aug 3, 2009
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        Thanks Steve for this although J Prop doesn't appear to have a UK agent which would be ideal.
        simon


        --- On Mon, 3/8/09, svlevity <phrf201@...> wrote:

        From: svlevity <phrf201@...>
        Subject: [campernicholson] Re: Denison Deri Hydraulic motor reduction ratio
        To: campernicholson@yahoogroups.com
        Date: Monday, 3 August, 2009, 11:06 AM

         

        Simon,

        We also have the Denison hydraulic drive and decided to buy a J Prop
        when we replaced ours. The J Prop is adjustable very quickly and easily
        under water, only takes 15-30 seconds. The person we spoke to at J Prop
        was the only one who seemed to truly understand the issue of reduction
        ratio relative to the hydraulic drive system. After having determined
        the diameter of the prop you are going to get, the easy adjustability of
        the J Prop makes the most sense. There was no need to modify the
        propshaft because the folks at J Prop will machine the prop-taper to fit
        your shaft. We're very happy with the J Prop.

        Steve Perry
        CN 80 Levity

        --- In campernicholson@ yahoogroups. com, Simon Frost <sfrost35@.. .> wrote:
        >
        > I am contemplating getting a feathering prop in the winter but need to know the reduction ratio for the Denison Deri M6-1 motor that runs off the original Perkins 4108. The Denison people based in Wakefield could not help as the motor is now extinct!
        >
        > Any thoughts and if so what feathering prop would be the best as it would need to exit straight out the back of the keel ie no P or A bracket fitted hence the reason that we struggle going astern! Currently we have the original 16'' x 8.5'' 2 bladed prop.
        >
        > Ideally a limited modification to the propshaft (1'' 1/8th diam) would be good
        >
        > Simon
        >
        > Samiotissa/62
        >


      • John Tapscott
        Simon, When I first bought Zuleika Vair she had the same fixed two bladed prop, hydraulic drive and engine you describe and we changed the prop for a 3 bladed
        Message 3 of 13 , Aug 3, 2009
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          Simon,

           

          When I first bought Zuleika Vair  she had the same fixed two bladed prop, hydraulic drive and engine you describe and we changed the prop for a 3 bladed Maxprop which has been very satisfactory for the last 8 or 9 years.  One of the reasons for choosing this was that there is no need for any form of brake on the shaft when sailing whereas it seemed most of the alternatives then available suggested one was necessary.  However changes to the pitch are only possible by taking the hub apart so it has to be done with the boat out of the water.  The shaft taper was no problem as it was taken into account by the firm which fitted it but I would add that the pitch set by them seemed to me to be too coarse so I have since reduced it.

           

          If you are interested in any further information please let me know and I would be happy to respond.

           

          Regards,

           

          John

           


          From: campernicholson@yahoogroups.com [mailto: campernicholson@yahoogroups.com ] On Behalf Of Simon Frost
          Sent: 03 August 2009 10:46
          To: campernicholson@yahoogroups.com
          Subject: [campernicholson] Denison Deri Hydraulic motor reduction ratio

           

           

          I am contemplating getting a feathering prop in the winter but need to know the reduction ratio for the Denison Deri M6-1 motor that runs off the original Perkins 4108. The Denison people based in Wakefield could not help as the motor is now extinct!

          Any thoughts and if so what feathering prop would be the best as it would need to exit straight out the back of the keel ie no P or A bracket fitted hence the reason that we struggle going astern! Currently we have the original 16'' x 8.5'' 2 bladed prop.

          Ideally a limited modification to the propshaft (1'' 1/8th diam) would be good

          Simon

          Samiotissa/62

           

        • J. Seth Strattan
          ... Simon - There are two ways to determine the reduction ratio: by calculation or by measurement. To calculate it you divide the motor displacement by the
          Message 4 of 13 , Aug 3, 2009
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            --- In campernicholson@yahoogroups.com, Simon Frost <sfrost35@...> wrote:
            >
            > ... need to know the reduction ratio for the Denison Deri M6-1 motor

            Simon - There are two ways to determine the reduction ratio: by calculation or by measurement. To calculate it you divide the motor displacement by the pump displacement. These displacements can usually be divined from the numbers stamped on the identification plates on the pump and motor. But as you found upon contacting Denison, old hardware can have a certain Rosetta Stone quality to it.

            Measurement is easy with a non-contact tachometer. I think I bought mine on Amazon for about $30. Search the web and you'll find a source for one. You use it to measure the prop shaft rotation speed. Divide engine RPM by prop shaft speed and you have your reduction ratio. It is best to measure it at cruising speed since there is some slip in the hydraulic system.

            Good luck!
            Seth
            Liberty, CN35 #21
          • rogerbentonuk
            Simon I have a copy of an article published in Practical Boat Owner(March 2001) titled More Power at the Prop in which Don Seddon examined the Nic 35
            Message 5 of 13 , Aug 3, 2009
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              Simon
              I have a copy of an article published in Practical Boat Owner(March 2001) titled 'More Power at the Prop' in which Don Seddon examined the Nic 35 hydraulic drive chain and mentions that the reduction ratio is 1.6 to 1.

              In the article he fitted a 16inch 3 bladed J prop set at 7.7 inch pitch though he then replaced the hydraulic pump and motor increasing the drive ratio to 1.95 to 1 and eventually settling on a pitch of 9inches.

              I have placed a copy of the article on my web site at the following URL:

              http://www.users.zetnet.co.uk/rbenton/Nic35_documents.html

              Like yourself I am thinking of fitting feathering prop so would be interested in what you decide to fit.

              Best wishes
              Roger
              Nic 35/86
            • Simon Frost
              Thanks Seth for the measurement tip. Very useful. Simon ... From: J. Seth Strattan Subject: [campernicholson] Re: Denison Deri Hydraulic
              Message 6 of 13 , Aug 4, 2009
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                Thanks Seth for the measurement tip. Very useful.
                Simon

                --- On Mon, 3/8/09, J. Seth Strattan <strattan@...> wrote:

                From: J. Seth Strattan <strattan@...>
                Subject: [campernicholson] Re: Denison Deri Hydraulic motor reduction ratio
                To: campernicholson@yahoogroups.com
                Date: Monday, 3 August, 2009, 8:09 PM

                 

                --- In campernicholson@ yahoogroups. com, Simon Frost <sfrost35@.. .> wrote:
                >
                > ... need to know the reduction ratio for the Denison Deri M6-1 motor

                Simon - There are two ways to determine the reduction ratio: by calculation or by measurement. To calculate it you divide the motor displacement by the pump displacement. These displacements can usually be divined from the numbers stamped on the identification plates on the pump and motor. But as you found upon contacting Denison, old hardware can have a certain Rosetta Stone quality to it.

                Measurement is easy with a non-contact tachometer. I think I bought mine on Amazon for about $30. Search the web and you'll find a source for one. You use it to measure the prop shaft rotation speed. Divide engine RPM by prop shaft speed and you have your reduction ratio. It is best to measure it at cruising speed since there is some slip in the hydraulic system.

                Good luck!
                Seth
                Liberty, CN35 #21


              • Simon Frost
                John, Thanks for that. It seems that Darglow ltd based in Salisbury are the UK Max Prop agents. They have a new Max Prop VP that can be adjusted externally
                Message 7 of 13 , Aug 4, 2009
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                  John,
                  Thanks for that. It seems that Darglow ltd based in Salisbury are the UK Max Prop agents. They have a new Max Prop VP that can be adjusted externally which sounds better. They also do their own so I will have a chat with them.
                  simon


                  --- On Mon, 3/8/09, John Tapscott <jrtapscott@...> wrote:

                  From: John Tapscott <jrtapscott@...>
                  Subject: RE: [campernicholson] Denison Deri Hydraulic motor reduction ratio
                  To: campernicholson@yahoogroups.com
                  Date: Monday, 3 August, 2009, 7:52 PM

                   

                  Simon,

                   

                  When I first bought Zuleika Vair  she had the same fixed two bladed prop, hydraulic drive and engine you describe and we changed the prop for a 3 bladed Maxprop which has been very satisfactory for the last 8 or 9 years.  One of the reasons for choosing this was that there is no need for any form of brake on the shaft when sailing whereas it seemed most of the alternatives then available suggested one was necessary.  However changes to the pitch are only possible by taking the hub apart so it has to be done with the boat out of the water.  The shaft taper was no problem as it was taken into account by the firm which fitted it but I would add that the pitch set by them seemed to me to be too coarse so I have since reduced it.

                   

                  If you are interested in any further information please let me know and I would be happy to respond.

                   

                  Regards,

                   

                  John

                   


                  From: campernicholson@ yahoogroups. com [mailto: campernicholson@ yahoogroups. com ] On Behalf Of Simon Frost
                  Sent: 03 August 2009 10:46
                  To: campernicholson@ yahoogroups. com
                  Subject: [campernicholson] Denison Deri Hydraulic motor reduction ratio

                   

                   

                  I am contemplating getting a feathering prop in the winter but need to know the reduction ratio for the Denison Deri M6-1 motor that runs off the original Perkins 4108. The Denison people based in Wakefield could not help as the motor is now extinct!

                  Any thoughts and if so what feathering prop would be the best as it would need to exit straight out the back of the keel ie no P or A bracket fitted hence the reason that we struggle going astern! Currently we have the original 16'' x 8.5'' 2 bladed prop.

                  Ideally a limited modification to the propshaft (1'' 1/8th diam) would be good

                  Simon

                  Samiotissa/62

                   


                • Simon Frost
                  Roger An interesting article with Don Seddons phone number as well so I will phone for some advice. Many thanks Simon ... From: rogerbentonuk
                  Message 8 of 13 , Aug 4, 2009
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                    Roger
                    An interesting article with Don Seddons phone number as well so I will phone for some advice.
                    Many thanks
                    Simon

                    --- On Mon, 3/8/09, rogerbentonuk <roger.benton@...> wrote:

                    From: rogerbentonuk <roger.benton@...>
                    Subject: [campernicholson] Re: Denison Deri Hydraulic motor reduction ratio
                    To: campernicholson@yahoogroups.com
                    Date: Monday, 3 August, 2009, 8:42 PM

                     

                    Simon
                    I have a copy of an article published in Practical Boat Owner(March 2001) titled 'More Power at the Prop' in which Don Seddon examined the Nic 35 hydraulic drive chain and mentions that the reduction ratio is 1.6 to 1.

                    In the article he fitted a 16inch 3 bladed J prop set at 7.7 inch pitch though he then replaced the hydraulic pump and motor increasing the drive ratio to 1.95 to 1 and eventually settling on a pitch of 9inches.

                    I have placed a copy of the article on my web site at the following URL:

                    http://www.users. zetnet.co. uk/rbenton/ Nic35_documents. html

                    Like yourself I am thinking of fitting feathering prop so would be interested in what you decide to fit.

                    Best wishes
                    Roger
                    Nic 35/86


                  • Thomas J Middelthon
                    Regarding propellers; I have mentioned it before to this group; Being the Norwegian agent for Brunton s Autoprop I can provide more info on props to anyone
                    Message 9 of 13 , Aug 8, 2009
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                      Regarding propellers;

                       

                      I have mentioned it before to this group;

                       

                      Being the Norwegian agent for Brunton’s Autoprop I can provide more info on props to anyone interested (send me an e-mail). And/or  see www.bruntons-propellers.com .

                       

                      With my 4.107 / hydr drive I get max rpm around 2500 , speed somewhere above 7 knots. Cruising 6 knots +, RPM 1500. On RPM 1100 I get 5-5,5 knots. Motor sailing is unbeatable due to automatic pitch.

                       

                      Price is in the region of GBP 1600-1700 and I think I should be able to help any one interested to get a good (better) price.

                       

                       

                      Thomas J. Middelthon

                      Nich 35 # 40, North Wind

                      Stavanger/Norway

                       

                       

                      From: campernicholson@yahoogroups.com [mailto:campernicholson@yahoogroups.com] On Behalf Of rogerbentonuk
                      Sent: 3. august 2009 22:42
                      To: campernicholson@yahoogroups.com
                      Subject: [campernicholson] Re: Denison Deri Hydraulic motor reduction ratio

                       

                       

                      Simon
                      I have a copy of an article published in Practical Boat Owner(March 2001) titled 'More Power at the Prop' in which Don Seddon examined the Nic 35 hydraulic drive chain and mentions that the reduction ratio is 1.6 to 1.

                      In the article he fitted a 16inch 3 bladed J prop set at 7.7 inch pitch though he then replaced the hydraulic pump and motor increasing the drive ratio to 1.95 to 1 and eventually settling on a pitch of 9inches.

                      I have placed a copy of the article on my web site at the following URL:

                      http://www.users.zetnet.co.uk/rbenton/Nic35_documents.html

                      Like yourself I am thinking of fitting feathering prop so would be interested in what you decide to fit.

                      Best wishes
                      Roger
                      Nic 35/86

                    • jorapazu
                      hello, which size was it, regards Jose Tethis cn35 #58
                      Message 10 of 13 , Aug 7, 2013
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                        hello, which size was it, regards
                        Jose
                        Tethis cn35 #58

                        --- In campernicholson@yahoogroups.com, "John Tapscott" <jrtapscott@...> wrote:
                        >
                        > Simon,
                        >
                        >
                        >
                        > When I first bought Zuleika Vair she had the same fixed two bladed prop,
                        > hydraulic drive and engine you describe and we changed the prop for a 3
                        > bladed Maxprop which has been very satisfactory for the last 8 or 9 years.
                        > One of the reasons for choosing this was that there is no need for any form
                        > of brake on the shaft when sailing whereas it seemed most of the
                        > alternatives then available suggested one was necessary. However changes to
                        > the pitch are only possible by taking the hub apart so it has to be done
                        > with the boat out of the water. The shaft taper was no problem as it was
                        > taken into account by the firm which fitted it but I would add that the
                        > pitch set by them seemed to me to be too coarse so I have since reduced it.
                        >
                        >
                        >
                        > If you are interested in any further information please let me know and I
                        > would be happy to respond.
                        >
                        >
                        >
                        > Regards,
                        >
                        >
                        >
                        > John
                        >
                        >
                        >
                        > _____
                        >
                        > From: campernicholson@yahoogroups.com
                        > [mailto:campernicholson@yahoogroups.com] On Behalf Of Simon Frost
                        > Sent: 03 August 2009 10:46
                        > To: campernicholson@yahoogroups.com
                        > Subject: [campernicholson] Denison Deri Hydraulic motor reduction ratio
                        >
                        >
                        >
                        >
                        >
                        >
                        > I am contemplating getting a feathering prop in the winter but need to know
                        > the reduction ratio for the Denison Deri M6-1 motor that runs off the
                        > original Perkins 4108. The Denison people based in Wakefield could not help
                        > as the motor is now extinct!
                        >
                        > Any thoughts and if so what feathering prop would be the best as it would
                        > need to exit straight out the back of the keel ie no P or A bracket fitted
                        > hence the reason that we struggle going astern! Currently we have the
                        > original 16'' x 8.5'' 2 bladed prop.
                        >
                        > Ideally a limited modification to the propshaft (1'' 1/8th diam) would be
                        > good
                        >
                        > Simon
                        >
                        > Samiotissa/62
                        >
                      • arnesenr
                        Hi, Regarding the hydraulic system, Iam considering changing the current British Filter house to spin off type but am a little worried that it might not allow
                        Message 11 of 13 , Aug 9, 2013
                        • 0 Attachment
                          Hi,

                          Regarding the hydraulic system, Iam considering changing the current British Filter house to spin off type but am a little worried that it might not allow enough fluid through. Has anyone changed out their filter system and is there a spec that has to be met?

                          regards,
                          RalphArnesen
                          Argonaut of Rhu, 8


                          Sent from Samsung tablet

                          jorapazu <e9a41@...> wrote:
                           

                          hello, which size was it, regards
                          Jose
                          Tethis cn35 #58

                          --- In campernicholson@yahoogroups.com, "John Tapscott" <jrtapscott@...> wrote:
                          >
                          > Simon,
                          >
                          >
                          >
                          > When I first bought Zuleika Vair she had the same fixed two bladed prop,
                          > hydraulic drive and engine you describe and we changed the prop for a 3
                          > bladed Maxprop which has been very satisfactory for the last 8 or 9 years.
                          > One of the reasons for choosing this was that there is no need for any form
                          > of brake on the shaft when sailing whereas it seemed most of the
                          > alternatives then available suggested one was necessary. However changes to
                          > the pitch are only possible by taking the hub apart so it has to be done
                          > with the boat out of the water. The shaft taper was no problem as it was
                          > taken into account by the firm which fitted it but I would add that the
                          > pitch set by them seemed to me to be too coarse so I have since reduced it.
                          >
                          >
                          >
                          > If you are interested in any further information please let me know and I
                          > would be happy to respond.
                          >
                          >
                          >
                          > Regards,
                          >
                          >
                          >
                          > John
                          >
                          >
                          >
                          > _____
                          >
                          > From: campernicholson@yahoogroups.com
                          > [mailto:campernicholson@yahoogroups.com] On Behalf Of Simon Frost
                          > Sent: 03 August 2009 10:46
                          > To: campernicholson@yahoogroups.com
                          > Subject: [campernicholson] Denison Deri Hydraulic motor reduction ratio
                          >
                          >
                          >
                          >
                          >
                          >
                          > I am contemplating getting a feathering prop in the winter but need to know
                          > the reduction ratio for the Denison Deri M6-1 motor that runs off the
                          > original Perkins 4108. The Denison people based in Wakefield could not help
                          > as the motor is now extinct!
                          >
                          > Any thoughts and if so what feathering prop would be the best as it would
                          > need to exit straight out the back of the keel ie no P or A bracket fitted
                          > hence the reason that we struggle going astern! Currently we have the
                          > original 16'' x 8.5'' 2 bladed prop.
                          >
                          > Ideally a limited modification to the propshaft (1'' 1/8th diam) would be
                          > good
                          >
                          > Simon
                          >
                          > Samiotissa/62
                          >

                        • Graham Norbury
                          If you can find the max flow specification of the hydraulic pump you should be able to find a filter than either matches or exceeds the flow figure. Graham
                          Message 12 of 13 , Aug 9, 2013
                          • 0 Attachment
                            If you can find the max flow specification of the hydraulic pump you should be able to find a filter than either matches or exceeds the flow figure.
                            Graham

                            On 08/09/2013 12:09 PM, arnesenr wrote:
                             
                            Hi,

                            Regarding the hydraulic system, Iam considering changing the current British Filter house to spin off type but am a little worried that it might not allow enough fluid through. Has anyone changed out their filter system and is there a spec that has to be met?

                            regards,
                            RalphArnesen
                            Argonaut of Rhu, 8


                            Sent from Samsung tablet

                            jorapazu <e9a41@...> wrote:
                             

                            hello, which size was it, regards
                            Jose
                            Tethis cn35 #58

                            --- In campernicholson@yahoogroups.com, "John Tapscott" <jrtapscott@...> wrote:
                            >
                            > Simon,
                            >
                            >
                            >
                            > When I first bought Zuleika Vair she had the same fixed two bladed prop,
                            > hydraulic drive and engine you describe and we changed the prop for a 3
                            > bladed Maxprop which has been very satisfactory for the last 8 or 9 years.
                            > One of the reasons for choosing this was that there is no need for any form
                            > of brake on the shaft when sailing whereas it seemed most of the
                            > alternatives then available suggested one was necessary. However changes to
                            > the pitch are only possible by taking the hub apart so it has to be done
                            > with the boat out of the water. The shaft taper was no problem as it was
                            > taken into account by the firm which fitted it but I would add that the
                            > pitch set by them seemed to me to be too coarse so I have since reduced it.
                            >
                            >
                            >
                            > If you are interested in any further information please let me know and I
                            > would be happy to respond.
                            >
                            >
                            >
                            > Regards,
                            >
                            >
                            >
                            > John
                            >
                            >
                            >
                            > _____
                            >
                            > From: campernicholson@yahoogroups.com
                            > [mailto:campernicholson@yahoogroups.com] On Behalf Of Simon Frost
                            > Sent: 03 August 2009 10:46
                            > To: campernicholson@yahoogroups.com
                            > Subject: [campernicholson] Denison Deri Hydraulic motor reduction ratio
                            >
                            >
                            >
                            >
                            >
                            >
                            > I am contemplating getting a feathering prop in the winter but need to know
                            > the reduction ratio for the Denison Deri M6-1 motor that runs off the
                            > original Perkins 4108. The Denison people based in Wakefield could not help
                            > as the motor is now extinct!
                            >
                            > Any thoughts and if so what feathering prop would be the best as it would
                            > need to exit straight out the back of the keel ie no P or A bracket fitted
                            > hence the reason that we struggle going astern! Currently we have the
                            > original 16'' x 8.5'' 2 bladed prop.
                            >
                            > Ideally a limited modification to the propshaft (1'' 1/8th diam) would be
                            > good
                            >
                            > Simon
                            >
                            > Samiotissa/62
                            >


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