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Thread: Rudder angle indicator

  1. #1
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    Default Rudder angle indicator

    Anyone have a suggestion for an old-fashioned rudder angle indicator ? New ones are easy to come by but they look so modern

    And no, I really don't want to disassemble one and make a new gage face, if I can possibly avoid it ...

  2. #2
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    Default Re: Rudder angle indicator

    Morse cable from the rudder quadrant to a simple pointer mechanism? Might be able to repurpose an old-style heel angle indicator?

    Like this one:


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    Default Re: Rudder angle indicator

    Quote Originally Posted by cstevens View Post
    Morse cable from the rudder quadrant to a simple pointer mechanism? Might be able to repurpose an old-style heel angle indicator?
    Whoa ! I like the clinometer part, that would look very in-period !

    But the cable part, mmmm. It'd be quite long and go around a bunch of corners. If this were 1950 we'd run over to the Army Surplus store and grab a couple of little servos from a B-29 or something ... model airplane stuff ?

  4. #4
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    Default Re: Rudder angle indicator

    Quote Originally Posted by Favorite View Post
    Whoa ! I like the clinometer part, that would look very in-period !

    But the cable part, mmmm. It'd be quite long and go around a bunch of corners. If this were 1950 we'd run over to the Army Surplus store and grab a couple of little servos from a B-29 or something ... model airplane stuff ?
    I doubt it would be too long to work effectively. The morse control cables on Perihelion were maybe 30' long with 90 degree bends plus some winding around. The cables from the outside station on Petrel are shorter than that but they have a 90 degree bend and a 180 degree bend before they get to the engine and gear. They work fine. And the cables are pretty inexpensive.

    I've seen at least one makeshift rudder indicator that just used the morse cable with a section of marked cable sticking out of the housing. As the rudder moved the end of the cable moved to show position. Could do something like that inside a brass tube with a view port for a simple but effective indicator. Fasten the morse cable to a second tube inside the view port tube with an engraved tick mark and then put some engraved ticks on the outer tube to indicate position. That would also look very in-period.

    Or... heck, you could get a brass bushing drilled for a set screw. Fasten that to the morse cable and then slide the viewport tube over the whole thing. The brass bushing would move as the rudder moves. Could look very cool.

  5. #5
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    Default Re: Rudder angle indicator

    Also I thought this question had come up before and...

    http://forum.woodenboat.com/showthre...ring-solutions

    it has. Might be some useful info there.

  6. #6
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    Default Re: Rudder angle indicator

    Quote Originally Posted by cstevens View Post

    I've a friend who calls this the divorce-o-meter.

  7. #7
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    Default Re: Rudder angle indicator

    Quote Originally Posted by cstevens View Post
    Also I thought this question had come up before and...

    http://forum.woodenboat.com/showthre...ring-solutions

    it has. Might be some useful info there.
    Thanks for the laugh ... "I never had one ! Can't imagine why you'd need one !" Give those guys a 38" prop and tell them to back around the marina, I'm guessing I could change a few minds

    Anyway, the simple solution is the last one (in that thread) - Wema (KUS now) or even VDO but the scales look so modern. I really like your clinometer idea the best. Or something visually similar to that ...

  8. #8
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    Default Re: Rudder angle indicator

    Years ago I made a rudder angle indicator for my dad who was a depression-era cheapskate and wouldn't buy one. The general concept is the same as a Wheatstone Bridge used in physics labs. Your problem will be finding a +\- voltage gauge that you like visually, or a milliamp meter and a resistor. Then get a pair of linear potentiometers (the sealed kind) parallel the outer contacts and take to DC plus and minus. Send the wipers of the pots to the terminals of the meter. One pot gets geared to the rudder stock somehow, the other is used to zero the whole mess. This was a Great Lakes boat and never had any problems, you might need to get more creative around salt air.
    ken

  9. #9
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    Default Re: Rudder angle indicator

    Honest question: When is a rudder indicator useful except when the boat is at the dock, at anchor or moored before unmooring? Even then, without one, can't you turn the helm to lock and return it to dead center to know the rudder is centered?
    Last edited by rbgarr; 12-01-2018 at 12:35 PM.
    If I had a dollar for every girl who found me unattractive, eventually they would find me attractive.

  10. #10
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    Default Re: Rudder angle indicator

    Quote Originally Posted by rbgarr View Post
    Honest question: When is a rudder indicator useful except when the boat is at the dock, at anchor or moored before unmooring? Even then, without one, can't you turn the helm to lock and return it to dead center to know the rudder is centered?
    When you are manuvering or backing up. I realize many people don't do that a lot, but it's kinda fun

    For a real-world example, I'm in a berth one berth from the end of a longish runway. The runway itself is maybe five feet wider than the boat is long. There's a concrete dock maybe twenty feet to port. This is a 34' boat with a 38" prop, so the the swing-to-port influence is pretty big.

    Back out to port with the rudder hard left. She'll swing that way okay, you get to about a 45 with the stern six inches off the boat parked opposite. Rudder full right then just work the forward-reverse and she'll spin in her own length, but also kind of walk sideways to port a little. (Just leave the rudder full right, when you reverse she swings to port no matter where the rudder is, so wheel-spinning just messes you up worse in this case.)

    At some point you are at maybe a ten to fifteen degree angle to the runway, about 105* from where you satrted, nose pointed towards the center of the runway but your ass is right up against the pilings to port. Now you want the boat to go *straight* and you'll come out nicely into the runway. If the rudder is right, your ass will swing into the pilings. If the rudder is left you'll nose over into the pilings before you can get any way on to correct. You would *really* like to be able to take a quick look at a rudder indicator to see you are truly pointed directly ahead.

    It's even worse if you've been spinning the wheel. Lots of times you don't want to stop and go all the way to the lock, then count back. The wind is blowing you off the dock while you count turns, oh goody. The king spoke is a quick indicator but with hydraulic steering, that can move around as the steering ram or the pump bypasses fluid.

    If you do much manuvering and your prop has much effect on how the boat handles, it's really not a superfluous luxury. Backing in general is another case where an indicator would be useful.

    Or a hot bimbo in a bikini to stand aft and call back the rudder position

    I loved Petrel's idea but that's gonna take a little construction work. A brass clinometer thingy would fit right in with the total ambience ... but meanwhile, maybe one of those cheap ebay things.

    p.s. Maybe ask Ian if he thinks a rudder indicator is useful ? He's got plenty wheel time on these things and maybe I'm just a sissy ...
    Last edited by Favorite; 12-01-2018 at 04:14 PM.

  11. #11
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    Default Re: Rudder angle indicator

    The king spoke is a quick indicator but with hydraulic steering, that can move around as the steering ram or the pump bypasses fluid.
    Yep. King spoke is not reliable ( there really is none) with hydraulic.

    Kevin
    There are two kinds of boaters: those who have run aground, and those who lie about it.

  12. #12
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    Default Re: Rudder angle indicator

    Quote Originally Posted by Favorite View Post
    Whoa ! I like the clinometer part, that would look very in-period !

    But the cable part, mmmm. It'd be quite long and go around a bunch of corners. If this were 1950 we'd run over to the Army Surplus store and grab a couple of little servos from a B-29 or something ... model airplane stuff ?
    I think mechanical is probably best, like a bicycle brake cable, but I am jammin' on the model airplane idea out of pure tech geekery: These servos respond to PWM signals, but they are really analog and could be used to respond to a crafted DC +/- signal. So they could be used for a bunch of interesting stuff as long as you buy the basic ones before everything goes digital and it all gets more complicated.......

    Ken

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    Default Re: Rudder angle indicator

    So this is a power boat thing? I’ve never even thought about having a rudder angle indicator before. But I’ve only had sailboats.

  14. #14
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    Default Re: Rudder angle indicator

    On sailboats, I've found that a tiller makes a fairly reliable rudder angle indicator.

    Tom
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  15. #15
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    Default Re: Rudder angle indicator

    Since I have a controllable pitch prop and need to know 'where it is' I have used a VDO rudder position indicator that is connected to the pitch control mechanism . No trouble with it A simple set up But does look 'modern'

  16. #16
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    Default Re: Rudder angle indicator

    I forgot this about hydraulic helms. What a PITA.
    Quote Originally Posted by Breakaway View Post
    Yep. King spoke is not reliable ( there really is none) with hydraulic.

    Kevin
    If I had a dollar for every girl who found me unattractive, eventually they would find me attractive.

  17. #17
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    Default Re: Rudder angle indicator

    Quote Originally Posted by kbowen View Post
    I think mechanical is probably best, like a bicycle brake cable
    I'd like to put it overhead dead center, and getting a cable up there would be non-trivial. You could do rods and bellcranks but ...

    I am jammin' on the model airplane idea out of pure tech geekery: These servos respond to PWM signals, but they are really analog and could be used to respond to a crafted DC +/- signal.
    Exactly. Seems like that would be easiest. But for the short term, maybe a modern one.

    In the meantime, if you get bored ...

    Quote Originally Posted by StevenBauer View Post
    So this is a power boat thing? I’ve never even thought about having a rudder angle indicator before. But I’ve only had sailboats.
    You don't normally push things around with a sailboat

    I did have a neighbor who liked to back into his berth under sail tho. We called him Showboat ...

  18. #18
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    Default Re: Rudder angle indicator

    When sailing the brig "Tre Kronor" this summer, I found the rudder indicator extremely useful.

    A relatively large ship like that reacts so slowly so it's really easy to lose track of where the rudder is at.
    Typically, you'd start to drift off course and try to compensate with a few spokes; nothing happens and you turn the wheel more; before you know it you've turned it two revolutions.
    But once the ship starts to get back on course it's time to turn the wheel the other way so the ship won't drift off course in the other direction.
    If the timing is off or if you over-/undercompensate, you'll have the ship sailing like a sinus wave instead of straight.

    /Mats
    Yes the avatar depicts me; yes I drew the comic boat pic, it's a joke on the pop song I'm not a robot by Marina and the diamonds

  19. #19
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    Default Re: Rudder angle indicator

    ^^^ Just.... wow.

  20. #20
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    Default Re: Rudder angle indicator

    A hydraulic "linkage" is another option using a pair of small double acting hydraulic cylinders one on the indicator and the other on the rudder would serve well.
    This setup could be easier to route with hoses over cables,the 1/8" nylon tubing with compression fittings is easy to install and route.........Once bled and calibrated this would be a trouble free system, although it will be more complex to initially build.

  21. #21
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    Default Re: Rudder angle indicator

    Quote Originally Posted by eggman918 View Post
    A hydraulic "linkage" is another option using a pair of small double acting hydraulic cylinders one on the indicator and the other on the rudder would serve well.
    Hmmm ... that's an idea I never would have thought of, but clever. Thanks !

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