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Re: engines

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  • billfye
    Here is a page full of boats that have been adapted for PWC (personal water craft) jet drive propulsion. Notably, some of Jim Michalak s designs have been
    Message 1 of 8 , Jan 3, 2004
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      Here is a page full of boats that have been adapted for PWC (personal
      water craft) jet drive propulsion. Notably, some of Jim Michalak's
      designs have been adapted.

      http://jetjon.homestead.com/page1.html

      Although in theory, it sounds like it shouldn't work that well, in
      practice it seems to be a really good way to power a boat while
      maintaining the shallowest draft.


      --- In bolger@yahoogroups.com, "tysond99" <tysond99@y...> wrote:
      > Happy Hollidays,
      > I wonder if anyone in this group has experience with outboard
      > jet drives. I have talked to designers who say that it is hard to
      > make an inboard/jet drive work smoothly because alot of air
      > (bubbles) are trapped under the hull and consequently fed to the jet
      > pump with a poor result in propulsion. I wonder if outboard jets
      > would work better since they can be adjusted for depth independent
      > of the hull.
      > On the Upper Delaware River where I live I see Carolina skiffs
      > going though 6" deep water at 20-30 MPH with 100/+- HP engines on
      > their transoms. Imagine how nice this might work on some of the PCB
      > sharpie boats.
      >
      > Don
    • dkb715
      Don, I have a Yamaha 115 HP 4 stroke outboard with a jet that I have mounted on a 19 sled I finished about 2 1/2 years ago. The boat has a modified V hull.
      Message 2 of 8 , Jan 3, 2004
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        Don,

        I have a Yamaha 115 HP 4 stroke outboard with a jet that I have
        mounted on a 19' sled I finished about 2 1/2 years ago. The boat
        has a modified V hull. Some of the other replies were right in that
        you lose about 25 - 30% of your power with the jet. You don't want
        the water intake hanging down significantly below the back of the
        transom (mine is pretty much even with it). The whole idea behind
        the jet is to allow you to travel in shallow water. It would also
        produce a lot of drag.

        The jet is also a real pig at slow speeds. Maneuverability is a
        major challenge, especially when docking. The inboard jets seem to
        be much better because they have a bigger bucket.

        Dave B


        --- In bolger@yahoogroups.com, "tysond99" <tysond99@y...> wrote:
        > Happy Hollidays,
        > I wonder if anyone in this group has experience with outboard
        > jet drives. I have talked to designers who say that it is hard to
        > make an inboard/jet drive work smoothly because alot of air
        > (bubbles) are trapped under the hull and consequently fed to the
        jet
        > pump with a poor result in propulsion. I wonder if outboard jets
        > would work better since they can be adjusted for depth independent
        > of the hull.
        > On the Upper Delaware River where I live I see Carolina skiffs
        > going though 6" deep water at 20-30 MPH with 100/+- HP engines on
        > their transoms. Imagine how nice this might work on some of the
        PCB
        > sharpie boats.
        >
        > Don
      • Don Tyson
        Dave B, How is reverse on your 19 Sled? Do you use reverse much while manuvering? dkb715 wrote: Don, I have a Yamaha 115 HP 4 stroke
        Message 3 of 8 , Jan 4, 2004
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          Dave B, How is reverse on your 19' Sled? Do you use reverse much while manuvering?


          dkb715 <lburright@...> wrote:
          Don,

          I have a Yamaha 115 HP 4 stroke outboard with a jet that I have
          mounted on a 19' sled I finished about 2 1/2 years ago. The boat
          has a modified V hull. Some of the other replies were right in that
          you lose about 25 - 30% of your power with the jet. You don't want
          the water intake hanging down significantly below the back of the
          transom (mine is pretty much even with it). The whole idea behind
          the jet is to allow you to travel in shallow water. It would also
          produce a lot of drag.

          The jet is also a real pig at slow speeds. Maneuverability is a
          major challenge, especially when docking. The inboard jets seem to
          be much better because they have a bigger bucket.

          Dave B


          --- In bolger@yahoogroups.com, "tysond99" wrote:
          > Happy Hollidays,
          > I wonder if anyone in this group has experience with outboard
          > jet drives. I have talked to designers who say that it is hard to
          > make an inboard/jet drive work smoothly because alot of air
          > (bubbles) are trapped under the hull and consequently fed to the
          jet
          > pump with a poor result in propulsion. I wonder if outboard jets
          > would work better since they can be adjusted for depth independent
          > of the hull.
          > On the Upper Delaware River where I live I see Carolina skiffs
          > going though 6" deep water at 20-30 MPH with 100/+- HP engines on
          > their transoms. Imagine how nice this might work on some of the
          PCB
          > sharpie boats.
          >
          > Don


          Bolger rules!!!
          - no cursing, flaming, trolling, spamming, or flogging dead horses
          - stay on topic, stay on thread, punctuate, no 'Ed, thanks, Fred' posts
          - Pls add your comments at the TOP, SIGN your posts, and snip away
          - Plans: Mr. Philip C. Bolger, P.O. Box 1209, Gloucester, MA, 01930, Fax: (978) 282-1349
          - Unsubscribe: bolger-unsubscribe@yahoogroups.com
          - Open discussion: bolger_coffee_lounge-subscribe@yahoogroups.com

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          [Non-text portions of this message have been removed]
        • doug6949
          Jet drives are not very efficient in terms of power conversion but they are quite common in whitewater boats. The folks down in NZ have them figured out. I
          Message 4 of 8 , Jan 4, 2004
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            Jet drives are not very efficient in terms of power conversion but
            they are quite common in whitewater boats. The folks down in NZ have
            them figured out. I think the Kiwi brand is Shotover. Jet boats were
            also popular in Idaho for awhile. I do not recall whether they were
            sterndrive or full inboard though. My guess is full inboard because
            they routinely jump sandbars, rocks and logs with them.

            This type of propulsion is even less efficient in displacement hulls.
            If shallow water is your main concern you might consider a Thai
            longshaft. Go-Devil is a popular American rendition of this idea. They
            are incredibly easy to build.

            Doug
          • dkb715
            Don, Reverse is not very efficient. Again, I think it s because the bucket on outboards isn t very large. (The bucket is the piece that moves up over the
            Message 5 of 8 , Jan 4, 2004
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              Don,

              Reverse is not very efficient. Again, I think it's because
              the "bucket" on outboards isn't very large. (The bucket is the
              piece that moves up over the jet to re-direct the water back to the
              sides.) I don't use reverse very much for this reason. If I need
              to hold myself in a current, I face into it. The other use is
              docking which isn't good.j

              I don't mean to sound too negative. I love the jet for running in
              the rivers. I can definitely go where others can't, and that's what
              it's for. For slow speed manuevering, it's not worth a hoot.

              Dave B


              --- In bolger@yahoogroups.com, Don Tyson <tysond99@y...> wrote:
              > Dave B, How is reverse on your 19' Sled? Do you use reverse much
              while manuvering?
              >
              >
              > dkb715 <lburright@c...> wrote:
              > Don,
              >
              > I have a Yamaha 115 HP 4 stroke outboard with a jet that I have
              > mounted on a 19' sled I finished about 2 1/2 years ago. The boat
              > has a modified V hull. Some of the other replies were right in
              that
              > you lose about 25 - 30% of your power with the jet. You don't want
              > the water intake hanging down significantly below the back of the
              > transom (mine is pretty much even with it). The whole idea behind
              > the jet is to allow you to travel in shallow water. It would also
              > produce a lot of drag.
              >
              > The jet is also a real pig at slow speeds. Maneuverability is a
              > major challenge, especially when docking. The inboard jets seem to
              > be much better because they have a bigger bucket.
              >
              > Dave B
              >
              >
              > --- In bolger@yahoogroups.com, "tysond99" wrote:
              > > Happy Hollidays,
              > > I wonder if anyone in this group has experience with outboard
              > > jet drives. I have talked to designers who say that it is hard
              to
              > > make an inboard/jet drive work smoothly because alot of air
              > > (bubbles) are trapped under the hull and consequently fed to the
              > jet
              > > pump with a poor result in propulsion. I wonder if outboard jets
              > > would work better since they can be adjusted for depth
              independent
              > > of the hull.
              > > On the Upper Delaware River where I live I see Carolina skiffs
              > > going though 6" deep water at 20-30 MPH with 100/+- HP engines
              on
              > > their transoms. Imagine how nice this might work on some of the
              > PCB
              > > sharpie boats.
              > >
              > > Don
              >
              >
              > Bolger rules!!!
              > - no cursing, flaming, trolling, spamming, or flogging dead horses
              > - stay on topic, stay on thread, punctuate, no 'Ed, thanks, Fred'
              posts
              > - Pls add your comments at the TOP, SIGN your posts, and snip away
              > - Plans: Mr. Philip C. Bolger, P.O. Box 1209, Gloucester, MA,
              01930, Fax: (978) 282-1349
              > - Unsubscribe: bolger-unsubscribe@yahoogroups.com
              > - Open discussion: bolger_coffee_lounge-subscribe@yahoogroups.com
              >
              > Yahoo! Groups Links
              >
              > To visit your group on the web, go to:
              > http://groups.yahoo.com/group/bolger/
              >
              > To unsubscribe from this group, send an email to:
              > bolger-unsubscribe@yahoogroups.com
              >
              > Your use of Yahoo! Groups is subject to:
              > http://docs.yahoo.com/info/terms/
              >
              >
              >
              > [Non-text portions of this message have been removed]
            • Don Tyson
              Are go Devils ever installed to utilixe remoe controls or must one stand by and hoist or steer manually? they are pretty simple and therefore atractive to me.
              Message 6 of 8 , Jan 4, 2004
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                Are go Devils ever installed to utilixe remoe controls or must one stand by and hoist or steer manually? they are pretty simple and therefore atractive to me.

                doug6949 <prototype@...> wrote:Jet drives are not very efficient in terms of power conversion but
                they are quite common in whitewater boats. The folks down in NZ have
                them figured out. I think the Kiwi brand is Shotover. Jet boats were
                also popular in Idaho for awhile. I do not recall whether they were
                sterndrive or full inboard though. My guess is full inboard because
                they routinely jump sandbars, rocks and logs with them.

                This type of propulsion is even less efficient in displacement hulls.
                If shallow water is your main concern you might consider a Thai
                longshaft. Go-Devil is a popular American rendition of this idea. They
                are incredibly easy to build.

                Doug


                Bolger rules!!!
                - no cursing, flaming, trolling, spamming, or flogging dead horses
                - stay on topic, stay on thread, punctuate, no 'Ed, thanks, Fred' posts
                - Pls add your comments at the TOP, SIGN your posts, and snip away
                - Plans: Mr. Philip C. Bolger, P.O. Box 1209, Gloucester, MA, 01930, Fax: (978) 282-1349
                - Unsubscribe: bolger-unsubscribe@yahoogroups.com
                - Open discussion: bolger_coffee_lounge-subscribe@yahoogroups.com

                Yahoo! Groups Links

                To visit your group on the web, go to:
                http://groups.yahoo.com/group/bolger/

                To unsubscribe from this group, send an email to:
                bolger-unsubscribe@yahoogroups.com

                Your use of Yahoo! Groups is subject to:
                http://docs.yahoo.com/info/terms/




                [Non-text portions of this message have been removed]
              • Don Tyson
                Dave I have to confess that I don t know a hoot about motor boats, having been a sailor for many years. I assume reverse is often used at moderate speeds to
                Message 7 of 8 , Jan 4, 2004
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                  Dave I have to confess that I don't know a hoot about motor boats, having been a sailor for many years. I assume reverse is often used at moderate speeds to slow or stop a motor boat. Reverse never worked on my sailboat on account of the boat being 8000lbs and the 8hp engine having only a 6" prop. When I hit reverse at 6 knts it took several hundred feet to stop the boat. I don't ever want that arrangement again.

                  dkb715 <lburright@...> wrote:Don,

                  Reverse is not very efficient. Again, I think it's because
                  the "bucket" on outboards isn't very large. (The bucket is the
                  piece that moves up over the jet to re-direct the water back to the
                  sides.) I don't use reverse very much for this reason. If I need
                  to hold myself in a current, I face into it. The other use is
                  docking which isn't good.j

                  I don't mean to sound too negative. I love the jet for running in
                  the rivers. I can definitely go where others can't, and that's what
                  it's for. For slow speed manuevering, it's not worth a hoot.

                  Dave B


                  --- In bolger@yahoogroups.com, Don Tyson wrote:
                  > Dave B, How is reverse on your 19' Sled? Do you use reverse much
                  while manuvering?
                  >
                  >
                  > dkb715 wrote:
                  > Don,
                  >
                  > I have a Yamaha 115 HP 4 stroke outboard with a jet that I have
                  > mounted on a 19' sled I finished about 2 1/2 years ago. The boat
                  > has a modified V hull. Some of the other replies were right in
                  that
                  > you lose about 25 - 30% of your power with the jet. You don't want
                  > the water intake hanging down significantly below the back of the
                  > transom (mine is pretty much even with it). The whole idea behind
                  > the jet is to allow you to travel in shallow water. It would also
                  > produce a lot of drag.
                  >
                  > The jet is also a real pig at slow speeds. Maneuverability is a
                  > major challenge, especially when docking. The inboard jets seem to
                  > be much better because they have a bigger bucket.
                  >
                  > Dave B
                  >
                  >
                  > --- In bolger@yahoogroups.com, "tysond99" wrote:
                  > > Happy Hollidays,
                  > > I wonder if anyone in this group has experience with outboard
                  > > jet drives. I have talked to designers who say that it is hard
                  to
                  > > make an inboard/jet drive work smoothly because alot of air
                  > > (bubbles) are trapped under the hull and consequently fed to the
                  > jet
                  > > pump with a poor result in propulsion. I wonder if outboard jets
                  > > would work better since they can be adjusted for depth
                  independent
                  > > of the hull.
                  > > On the Upper Delaware River where I live I see Carolina skiffs
                  > > going though 6" deep water at 20-30 MPH with 100/+- HP engines
                  on
                  > > their transoms. Imagine how nice this might work on some of the
                  > PCB
                  > > sharpie boats.
                  > >
                  > > Don
                  >
                  >
                  > Bolger rules!!!
                  > - no cursing, flaming, trolling, spamming, or flogging dead horses
                  > - stay on topic, stay on thread, punctuate, no 'Ed, thanks, Fred'
                  posts
                  > - Pls add your comments at the TOP, SIGN your posts, and snip away
                  > - Plans: Mr. Philip C. Bolger, P.O. Box 1209, Gloucester, MA,
                  01930, Fax: (978) 282-1349
                  > - Unsubscribe: bolger-unsubscribe@yahoogroups.com
                  > - Open discussion: bolger_coffee_lounge-subscribe@yahoogroups.com
                  >
                  > Yahoo! Groups Links
                  >
                  > To visit your group on the web, go to:
                  > http://groups.yahoo.com/group/bolger/
                  >
                  > To unsubscribe from this group, send an email to:
                  > bolger-unsubscribe@yahoogroups.com
                  >
                  > Your use of Yahoo! Groups is subject to:
                  > http://docs.yahoo.com/info/terms/
                  >
                  >
                  >
                  > [Non-text portions of this message have been removed]


                  Bolger rules!!!
                  - no cursing, flaming, trolling, spamming, or flogging dead horses
                  - stay on topic, stay on thread, punctuate, no 'Ed, thanks, Fred' posts
                  - Pls add your comments at the TOP, SIGN your posts, and snip away
                  - Plans: Mr. Philip C. Bolger, P.O. Box 1209, Gloucester, MA, 01930, Fax: (978) 282-1349
                  - Unsubscribe: bolger-unsubscribe@yahoogroups.com
                  - Open discussion: bolger_coffee_lounge-subscribe@yahoogroups.com

                  Yahoo! Groups Links

                  To visit your group on the web, go to:
                  http://groups.yahoo.com/group/bolger/

                  To unsubscribe from this group, send an email to:
                  bolger-unsubscribe@yahoogroups.com

                  Your use of Yahoo! Groups is subject to:
                  http://docs.yahoo.com/info/terms/




                  [Non-text portions of this message have been removed]
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