Let's talk rudders

Discussion in 'General Paddling Discussions' started by RichardH, May 6, 2008.

  1. mick_allen

    mick_allen Paddler & Moderator

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    Not in this thread, we love to see the various alternatives – especially well thought out ones.

    It is so very interesting that both you and Sandy have very serious rudders. They don’t have the spit and polish of manufactured rudders but their beauty lies in the great thought and engineering that you both have put into them.

    Turning to your rudder specifically the points that I note about it are:
    • - It is a ‘transom hung’ rudder that has a long and substantial housing hinge that encompasses the full height of the ‘transom’
      - The housing drops almost to the water level and supports and stabilizes the blade to the maximum but just stops short of causing drag.
      - A partial concealing slot into the deck that the rudder must be aligned with by feel [or experience] to reduce windage, provide strength on the beach or in transit, and possible provide a little less obstruction.
      - Substantial construction.

    I’m surprised you expose the retracting lines while hiding the rudder lines, but very interesting that you cross those rudder lines – I bet only a few percent of paddlers do that. It’s counterintuitive to traditional aeronautical rudder pedal orientation, but not to foot bracing and lean for kayaks. Did it take you long to get used to it or did you always do that? [ I would always keep it traditional to not get confused and I think the gas pedal bracing means there’s little detriment- but just a thought]

    The transom [or more exactly stem or ‘frame’] hung rudder was its greatest advance because of the great strength and protection provided by that member. Historically the blade base was aligned or slightly above the keel for that protection, but keeping the housing just above water level and having a rotating blade allows similar safety as it can move out of the way and the highish housing is well protected - more than a traditional. Taking full advantage of the height of that stem/transom for both strength and housing stability just makes full sense.

    Of course there are a bunch of these out there by manufacturers and even another slightly misguided by one of your fellows in NZ:


    The VCP C-trim shows an inset similar to yours but the others show the basic qualities of transom hungs and extended housings to a varied degree. Those rudders basically get it: good transom connection, similar sized housing to rudder blade head size and a housing that extends to some degree depending on the rudder. More would be better in some cases.

    But essentially the designer comprehends the issues and advantages that this approach allows . . .

    But have a look at the following transom hung rudders. I won’t name any names, but this first one demonstrates that the designer has absolutely no idea of what the issues are or how to respond to them. But look at the nice clean materials and the nice curves and shapes that make up its form:


    How can one say that JKA’s roughish rudder is beautiful in comparison to the above well rendered rudder example? What aspects of a transom hung rudder are missed here to the point of being simply ludicrous? Does function have beauty over form? Can form be ugly?

    So that’s an unnamed recreational kayak, but what excuse does a well-known and respected sea and whitewater kayak company have for doing essentially the same thing with this example of misunderstanding the beneficial aspects of this approach:


    Now good transom hung rudders have their drawbacks just like any other good rudder has: the simplest is there needs to be a transom [or a verticallish stem in our case]! And for the kayak to be well designed for these, it needs to be of the type that has a ‘transom’ – and not some blobbed on extension or extrusion or hacked off mistake that completely negates the original lines of that particular kayak.
     
  2. Mac50L

    Mac50L Paddler

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    John gave a talk to our network last Wednesday about fitting out kayaks and crossed rudderlines were mentioned. One member, a pilot, definitely wouldn't go that way, another member (2?) do use crossed lines. When pushing with the foot, crossed-lines, you are mentally pushing the kayak round in the direction you want to go rather than thinking about pushing the rudder in the direction you want it to move.

    John, that does look like a Nordkapp because of the hollow stern sections.

    Rudders and hanging them - so many look like an afterthought and are. Prijion is/was the worst by hanging them on top of an up-swept stern to keep the blades from getting wet and as far aft as possible, aft of the end of the hull.

    My rudder blades are as close to the stern as it is possible to place them and they are retracted by pulling up on the top of the blade so it retracts 90 degrees and must retract straight along the hull. All lines disappear into the hull level with the top of the retracted rudder on the deck. The rudder system was designed by Don Currie, produced by two manufacturers in NZ and a decade later "patented" by KajakSport and a decade after that "patented" by Sea-Lect. Neither patent would actually stand up and no way would they stop us producing them.

    http://www.kask.org.nz/rudders/#more-333

    Note - the pictures are not of one of my design kayaks or rudder builds but show how it retracts. Yes, I "stole" the pictures from the company that stole the design.

    Sisson tended to leave his rudderlines exposed and easy to get caught-up when doing rescues etc.
     
  3. JKA

    JKA Paddler

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    Hi Scott,

    You're correct, that eunuch-creating machete hanging on the stern is a no-go zone. I think of kayaks and helicopters the same: The back is a danger zone unless it's sleeping and tied down! :D

    Hi Mick,

    "Does function have beauty over form? Can form be ugly?"

    Wow, that's deep! :wink: Excuse the pun.

    That photo of Conrad's worm-eaten rudder always makes me laugh. As I remember it, at a symposium Paul Caffyn was sending people to see my first rudder, on a Necky Arluk 1.8, claiming it was the best he had seen but it was too heavy. Conrad, who often paddles with Paul, was seen studying mine and soon his holy version appeared. :D

    Re the crossed rudder cables, I changed to those simply because it made sense to me, I don't recall hearing about them before I did it. It was actually quite easy to learn, as railing to steer was something I had always done. I did have "a moment" when I was first trying it out on a flat river and I was overtaken by a bunch of paddlers in K1's. They were close to me so I "adjusted" to give them room. It's fair to say that ramming and capsizing two K1's gets quite a reaction! :twisted:

    I now can't paddle a kayak fitted with "conventional" un-crossed cables so just leave the rudder up.

    One point I would make to those who say we need to learn to control a kayak with edging and strokes "in case the rudder breaks".

    I think it is important to learn to paddle for the situations when a rudder simply won't work. No forward speed, strong side winds, tight manoeuvring. These are when boat-control skills are needed and a rudder doesn't cut it. When instructing in boat control I always make paddlers retract their rudders, but before I do I demonstrate how tight turns at low speed are impeded by a deployed rudder.

    Watching someone struggling to turn upwind with a rudder deployed is frustrating. Flick that beast up and watch the joy on their face. :D

    Cheers

    John
     
  4. Mac50L

    Mac50L Paddler

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    John's comment - "in case the rudder breaks" was one Don used to comment on by telling us why 747 passengers are instructed on how to run up and down the cabin in case the rudder breaks. He was probably the most scathing person about the broken rudder excuse.

    Should instruction on handling without the rudder be given? Most definitely as it has its place.

    Incidentally John, I'm in Wakefield at present and we didn't take our kayaks this trip, just bikes.
     
  5. Mac50L

    Mac50L Paddler

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    Weight and good design - a certain NZ paddler who is obsessive about weight lent one of his Nordkapps to a visiting Swedish kayaker for a month or so of paddling about the country. It had a leak around the rudder mounting due to poor design and because a proper fix would be visible, and weigh ~50 gram we did a possibly temporary fix by pouring 200+ gram of epoxy in inside to block the leak. I had made up the proper fix components so knew how light they'd be.

    I suspect John knows who I'm talking about, owner, paddler and kayak builder.

    And the message? Think about what and how things work, the mechanics of it all, what is really happening. If you can't, find someone who can. And that's not necessarily the manufacturer who caused the problem in the first place!
     
  6. mick_allen

    mick_allen Paddler & Moderator

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    "turn upwind with a rudder deployed" - I was told to just turn the boat around and paddle backwards! [But maybe they were trying to get rid of me. ]

    "run up and down the cabin: - That’s nuthin. The killer kayakers up here have a line to each hatch-lid and just pop the appropriate one for that maneuver.
    Slalom is a problem, though - but I heard it seems to work in the vertical sense, but no one knows for sure as those guys seem not to be around for some reason.

    *
    Aside from the humour attempt, Scott’s next comment:

    "deter a cowboy scramble"
    That comment on damage to person or rudder, exposure to or from rescued victim damage, exposure to damage on beaching, exposure from others or objects, interference with towing etc. all seem to be powerful issues against our exposed rudders types. Clamouring over the deck in seas with deploy lines, tow lines and exposed blades in the cold waters seems like it would be a big issue . . . and trying to pull someone or some boat with a longish tow seems like an entanglement issue or at least a real hassle with the rotator and tiller sticking up.

    So following the above and the last comment about minimal mechanics:

    You can tell the extremely serious rudder users here like John JKA , Sandy Mac50L, Doug Lloyd and others - by what they say, do, and show. But I’m just a dilettante in all this – my only entry ticket is strong interest – but I have always thought that a robust completely internalized system like a slot rudder would be the holy grail for rudder users because of that minimal exposure. Why is there not clamour for such a thing from committed users who have all this metal mechanism, lines, and blade exposed to hazard or cause hazard?

    Some of the hunt and peck systems shown previously here are not that great, and would take a little time to get used to, but the rudder performance would be so much better as well as all the mechanisms internalized - that wouldn’t it be worth trying or mocking up a few?
     
  7. Mac50L

    Mac50L Paddler

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    "deter a cowboy scramble"
    "That comment on damage to person or rudder, exposure to or from rescued victim damage,"

    The cockpit is in the middle of the kayak so why go to the furthest point from it (the stern)? Also so many kayaks without rudders have upswept ends so again the rudder deterring rescues doesn't make sense to me.

    "... exposure to damage on beaching, "

    That's why you stow it first.

    "... interference with towing etc."

    Tow line over the side so it doesn't get caught by the upswept stern (or rudder).

    "... all seem to be powerful issues against our exposed rudders types."

    Which shows how "grasping at straws" the arguments against rudders are.

    " Clambering over the deck in seas with deploy lines, tow lines and exposed blades in the cold waters seems like it would be a big issue . . ."

    So you do your rescue, self or two boat, over the side and into the cockpit. Admittedly those who run rudder cables on deck instead of under the deck are doing a dis-service.

    "... and trying to pull someone or some boat with a longish tow seems like an entanglement issue or at least a real hassle with the rotator and tiller sticking up. "

    As above, the non-rudder high stern is just as much an argument against that comment.

    "So following the above and the last comment about minimal mechanics: Why is there not clamour for such a thing from committed users who have all this metal mechanism, lines, and blade exposed to hazard or cause hazard?"

    Because they are not an issue and never have been.

    The critical item is good design and unfortunately there are so many poor designers in the world like who sold the sliding rudder pedals or Smarttrack vertical stow blade etc., etc.
     
  8. mick_allen

    mick_allen Paddler & Moderator

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    That’s a showstopper of a statement if there ever has been .

    But you infer the contrary when you state that they are no ‘more’ problem than an upswept end or that you have to now side-tow than rather than from a more typical central [straw grasping? ] position, or that boats don’t roll over on the beach upon surf landing, or that cowboy scrambles cannot start from the back and that any part of a victim now should only be away from that rear section of the boat.

    Haven’t you ever walked into one: torn or caught your drysuit legs on one in shore, had problems lifting the stern, backed into obstacles, consciously avoided with your feet in victim practice, avoided when paddling with someone else, had more side-windage or side-wash than you wanted? Some of those situations have certainly happened to me – but it’s true, I am a little clumsy . . .

    So I think that you are overstating it somewhat, otherwise kayak rudder development never got past NZ 3 decades ago – and yet I venture your specific T-bar rudder is a more sophisticated approach than even that! When you close your eyes and have rudder dreams, don’ t you imagine slick upswept or say swept pointed sterns – ie all kayak forms - that are as well served as any transom ruddered kayak?

    I do.
     
  9. JohnAbercrombie

    JohnAbercrombie Paddler

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    I think you are catching on, Mick. :D
     
  10. JKA

    JKA Paddler

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    :clap:

    The hammer has cleanly struck the target! Someone who knew him very well once told me that Paul Caffyn was the best thing that had happened to sea kayaking in NZ, and the worst thing! Paul was a pioneer, and like many who "boldy go", he is strong willed. This has dictated many aspects of sea kayaking, not just in NZ.

    To the points raised (pun not intended) about rudders and their terrible entanglement-tendencies, anyone who argues otherwise is possibly showing their lack of experience in towing in the real world...

    I'm sorry if I have drifted this thread into an argument about the pros and cons of rudders. My first post showed my concern about this.

    Cheers

    John
     
  11. mick_allen

    mick_allen Paddler & Moderator

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    No problem, this is a straight forward rudder thread: the issues [accepted or not] raised about any particular or group rudders are just a natural part of the discussion.

    And anyone who has read more than a few of Sandy’s [Mac50L] posts knows that he is strong NZ patriot who is annoyed that due credit is not given to early NZ slider rudders designers [Don Currie] and sliding footpeg designers. But getting past that, he has a wealth of experience, knowledge and particular attention to engineering detail shown by his own unrecognized unique approach to the sliding transom rudder.

    [To the ‘lack of experience’ comment, that’s a hit I have and always will been guilty of in anything:
    But if one only ‘side tows’ so as to not have a rudder entanglement issue, I would venture that the issue still exists for all those who tow using central methods. I fully accept that it is not an issue for you – but I think it is for others. It is more than a drag[!] for pulling swimmers.]

    In any event, I think there are two wider issues here:
    1) If serious rudder users and rudder users in general are essentially satisfied with the features that the rudders of this day give to them, there will be minimal pressure to design or attempt to develop new or different rudder approaches.
    2) If serious rudders and upswept or strongly inclined sterns are incompatible [aesthetically and/or functionally], then a huge proportion of our kayaks are excluded from having serious rudders.

    Kayak and sailboat rudders have both had some interesting evolvements from the medieval transom/stem hung rudder. The main one for us is the 270 degree overstern blade retraction for both transom-hung and pinhead rudders. The second one is the much maligned [by me] pinhead rudders which are a pseudo-legitimate response to attaching a rudder to an inclined or upswept end.

    Sailboats started the rearward rotation retraction with partial retractions typically up to the 120 degree mark and have gone on to other resolutions that don’t really apply to us like the cartridge rudder, the drum rudder but one that could be the idea germ for the sliders – the Dick Newick kickback rudder.

    And now coming into more popular notice, the most stringent rudder requirement of all: the proa rudder that at its ultimate needs to be bidirectional, a rigid foil, and auto retractable from both directions [hopefully from impact as well] – all in one rudder! The proa doesn’t tack, it ‘shunts’ backward and forward – there is no bow or stern. A provocative design task.

    But I think differently: that these issues [whatever the accepted ones are] with our rudders in general that should cause inclination to try and find more approaches: if nothing else we have to come up with some other simple approach than pinhead rudders for our delicately shaped and elegant upswept ends.

    Karitek was an attempt, but big cost, outlandish complexity, outsized housing, and small rudderblade, and questionable [by me] action, all were strikes against it. But there has been no other rudder released like it. The ‘hunt and peck’ers all [except the Thomasson, which doesn’t fit V hulls] use ambiguous insets and small rudderpost hinging that will quickly wear and wobble.

    **
    an aside from the discussion:

    But you know me by now: I think it’s a crying shame . . . and I think, or hope, some of us are interested in other approaches that maybe can minimize some of the smaller issues and also apply to our widely differing kayak forms and yet still be a simple, robust approach.
    So sometime in the near future I’ll put one family of the many other approaches I know of out in a related thread. For fun and fame. It’s called the ‘revo rudder’.
     
  12. Mac50L

    Mac50L Paddler

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    Hunting for details showed me something like the rudders (Skudder ?) designed and fitted to a couple of Skerrays in NZ, years ago. These were to replace the non-steering skegs. Nothing new there as they have been around for decades.

    One major problem with a skeg is the lost stowage capacity in a touring sea kayak or certainly in a narrow one.
     
  13. mick_allen

    mick_allen Paddler & Moderator

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    I'd sure like to see pics of a few of those, because the only one I saw some time ago [and didn't copy, darn it] was one of the many hunt and peck versions that pple and european manufacturers made long ago as well.
     
  14. Gary Jacek

    Gary Jacek Paddler

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    Some time ago, Dan wrote "How many rudders actually break? ".

    Some years ago I performed a particularly graceless surf landing at Catalla Island in Esperanza Inlet.
    The Feathercraft rudder on my Nimbus Telkwa was in the "up" position. Unfortunately, "up" is really "down" when you arrive at the shore, inverted.

    The result was that the aluminum "fin" had a very slight bend.

    While performing my Fall maintenance, I decided it was a good time to take apart the rudder mechanism so I could remove the fin and heat/straighten or replace it. During disassembly the "Delrin Block" fell to pieces in my hands. That's the bit that everything else bolts into, so any real stress would have disintegrated my rudder system in the field. Not a happy thought.

    One phone call to Feathercraft in Vancouver and a new Delrin Block arrived promptly for the repair.

    Sadly, Feathercraft went out of the kayak business just this week. :(
     
  15. mick_allen

    mick_allen Paddler & Moderator

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    So 1200 AD or thereabouts: around the time that New Zealand had been first colonized by anyone:


    About 2 months ago, I heard about Zhang Zeduan and started looking at his 1125 AD tapestry of life along the river. . .

    I just about fell out of my chair as I was seemingly looking at a New Zealand kayak type retractable rudder that possibly predated New Zealand itself!

    Now admittedly it didn’t fully slide onto the deck, but it did have axial as well as rotational retraction . . . and it did have lines or even chains performing the retraction.
    And it didn’t have a remotely operated tiller, but it maybe could be forgiven for that.

    And even though they are probably kickbackcontrollers as well, it even looks like there is an offset rotational axis pin!

    Quite astounding: 1125 AD - almost 1 millenia ago and well developed even then.
    Oh yeah, balanced blades.