Kitchen rudder

Discussion in 'Boat Design' started by duluthboats, Mar 8, 2002.

  1. timswait
    Joined: Jul 2008
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    Location: UK

    timswait Junior Member

    OK, I've gone and done it! Put a kitchen rudder on the narrow boat I'm building, there's some pics below. I'm going to go with the tiller that lifts up and down for operating the shells, as in the video above, and just have to see what the control effort involved is like. I'll put a locking pin in the hinge so it can be locked in the fully open position and stay there. I have a conventional reverse gear in the gearbox to fall back on if the rudder doesn't work or is just unacceptably heavy to close. Should be on the water fairly soon, so watch this space to see if it works!
     

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  2. ben2go
    Joined: Jul 2008
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    ben2go Boat Builder Wanna Be

    Is this rudder made for your boat or retrofitted from a salvaged rudder?Either way,it looks great.I see no problems with it.
     
  3. timswait
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    timswait Junior Member

    It's made for my boat. I 'designed' (plucked from thin air might be a better description) the shape of the clamshells and machined the tubes and bearings (nylon bushes). I was going to try and fabricate the clamshells too, but am running out of time for this this project, so I got our boat builder to do that for me.
     
  4. duluthboats
    Joined: Mar 2002
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    duluthboats Senior Dreamer

    It looks great Tim, the admiral is smiling.
    Gary:D
     
  5. jrpat
    Joined: May 2009
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    Location: New Zealand

    jrpat WHATI

    I'm new here, but having read all the information here I have decided that I want to install a Kitchen Rudder on our 1940's Kauri launch. This would need to be hydraulically operated, and will need to be assembled in the boat - without welding as there is no room at all at the top of the rudder shaft. Any suggestions for the mechanical connection here, given the stresses on all the parts involved?
     
  6. timswait
    Joined: Jul 2008
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    timswait Junior Member

    Well, the boat's on the water and I think the rudder can be counted as a success. Haven't got any particularly good photos of it in action yet, or of the linkage, but you can just about make it out in this one. It works in the manner of the video I posted earlier.
    In forwards it's very responsive (for a 60 foot long narrowboat ;) which if you don't hail from the UK you might not realise how unresponsive this would normally be!) and also nicely balanced. It doesn't self-centre, but it will stay wherever you put it very steadily. The clamshells have a tendency to close up as you put power on to get underway, so you have to hold force down on the tiller (although not very much) but once you're moving you can let go of the tiller and there's no tendency to close up. I have a locking pin I can use to lock it in the fully open position, but have found that's more hassle than it's worth.
    The only problem with the boat is that it's under ballasted, so the top of the clamshells are just out of the water. This makes the prop cavitate wildly as you set off and makes it slow to get moving (both forwards and reverse). Once the boat gets moving it sucks itself down a little (shallow channels here) and it all gets much better.
    Once you lift the tiller a little to close the clamshells it will try to close the rest of the way. It's not too much force to hold since the speeds are so low (mostly less than 4 knots), but it would be too heavy if higher speeds were involved. As a water brake it's excellent, my girlfriend nearly fell off the handrail into the water the first time I tried it! It slows very rapidly initially, but then stopping the last little bit and starting moving in reverse takes more time, probably the under ballasting issue mentioned earlier. The only real vice is that in the full astern position the tiller does try and pull across hard to one side, and it needs quite a lot of force to bring it back to centre. But the flip side of that is that it manoeuvres the boat very effectively in the reverse position. I can still steer while going forwards and braking hard, and can use it as a stern thruster to spin the boat around on the spot, which wouldn't be possible on a boat like this without a bow/stern thruster at about 10 times the cost. So overall very successful, but I need to get some more weight in her to try it out more effectively.
    jrpat: You can certainly design something that fits together without welding. Look at the top of the clamshell in the picture of mine in the full open position. You can see the clamp I made to attach the clamshell to the shaft, you could do something similar on the top end. The clamp is a chunk of mild steel bar 70 mm dia, concentrically bored through to be a tight interference fit on the shaft. It is cut lengthwise down the middle, most of the way through with two bolts to pull the two halves together so that when you tighten them it pulls the two halves together and clamps them onto the shaft. For extra security the two bolts actually notch through the shaft so that even if the assembly works loose they will catch on the shaft and stop it turning more than a few degrees. Probably the biggest challenge with retro-fitting a kitchen rudder that I can see is having to fit a longer stern tube and propshaft to move your prop backwards so it's directly under the tiller pivot, that might mean some disruption of your drive system. Either that or making a new tiller pivot that's further forwards to bring it over the prop. re the stresses, yes they are quite high, higher than for a conventional rudder, especially if you throw it into full reverse at a fair speed (I don't know how fast or how heavy your boat is), so just over-engineer where possible, and make sure that whatever the steering shaft is attached to is man enough for it.
     

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  7. ben2go
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    ben2go Boat Builder Wanna Be

    Good work.Thanks for keeping us informed on how the rudder handles.
     
  8. duluthboats
    Joined: Mar 2002
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    duluthboats Senior Dreamer

    Tim, that’s a pretty good report and a fantastic effort to go from concept to execution so quickly. :D
     
  9. jrpat
    Joined: May 2009
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    Location: New Zealand

    jrpat WHATI

    Thanks so much for the detailed information, it is very much appreciated.
    My boat is a 3 ton carvel planked launch, and the kitchen rudder is on my long-term "to do" list. Have a number of more pressing projects to get done first.
    Extending the drive train should not be too much of an issue as the prop is already very close the rudder pivot point. Will be installing a new motor/gearbox and Aquadrive in her this year, and will have to trim the prop shaft to fit everything in - even with the prop moved aft a bit.
    Thanks again, John.
     
    Last edited: Jun 6, 2009
  10. BCM
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    BCM Junior Member

  11. ben2go
    Joined: Jul 2008
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    ben2go Boat Builder Wanna Be

    Just a thought,but I think this rudder set up would be perfect fit on a Rescue Minor/Seabright Skiff.
     
  12. artemis
    Joined: Oct 2004
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    artemis Steamboater

    I think it would work well on a Seabright Skiff, but not so sure about Rescue Minor or any of the other tunnel stern Atkin boats. Two possible problems:
    1. When turning part of the prop wash would impinge on the tunnel and the resultant resistance might counter the direction of turn;
    2. When going astern the prop wash would be channeled back through part of the tunnel, again possibly countering the direction. Don't know but something to consider/test:?:
     
  13. surenw2005
    Joined: Dec 2009
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    Location: Sri Lanka

    surenw2005 New Member

    Kitchen Rudder Drawings.

    Appreciate if you could e-mail to me at suren@uk2.net the drawings of the kitchen rudder designed by you. Thank You.
     
  14. rayman
    Joined: Sep 2009
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    rayman Senior Member

    well, it's good to see this oldie being revived. Kitchin rudder I mean. I drove a survey launch (about 40') back in the 70's fitted with one. It gave precise control when running lines around wharves and suchlike, took some getting used to though.Engine was a Cummins, about 150 hp. just set the revs about 3/4 throttle and away you go, one hand controled the course, the other the forward/reverse, engine just bellowed away. Yes they would be a P.I.T.A. doing things the navy way all the tooting-peeping-whistle blowing and armwaving. There are three things you don't need on a small vessel--A bicycle--an umbrella--and a naval officer
     

  15. dskira

    dskira Previous Member

    Nice. I always thouth it was worth studiing more the Kitchen rudder.
    Cheers
    Daniel
     
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