Yacht steering pedastal/steering wheel designs

Discussion in 'Boat Design' started by JosephT, Apr 2, 2012.

  1. JosephT
    Joined: Jun 2009
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    JosephT Senior Member

    Read this story over the weekend and thought it might be a good idea to discuss unforseen loads on steering pedastals.

    http://thelede.blogs.nytimes.com/20...wave-overtakes-yacht-in-round-the-world-race/

    The word is “Just before the sun came up, a monstrous foaming swell broke over our stern,” he went on, adding: “We had no steering, and crew were falling all over the boat.”

    From what I have studied, most steering pedestals are designed to deflect waves nicely if they come from over the bow or at slight angles coming off the bow/forward end of the boat.

    However, rogue waves from the aft & beam (sides) of a boat can directly hit the pilot & steering pedestal.

    I'm wondering whether there are any cockpit designs out there that are designed to re-direct/reduce the impact of big waves coming from the stern or sides.

    Below is a pic of the boat as the Coast Guard rescue was taking place. It's quite clear the stern/aft cockpit area is all but totally exposed and really doesn't offer any protection from a incoming stern/beam rogue wave.

    [​IMG]

    In this case, the result was the helmsman was smashed forward into the steering wheel (injured back, ribs). When you lose steering the boat is obviously out of control and in this case several other crew members suffered injuries. Fortunately the hull held up well so overall these are tough boats.

    Piloting errors aside, from my perspective the rear cockpit should be design so that the stern of the boat is at least partially protected to allow the helmsman to crouch and miss a direct hit by a wave. It seems a rear/side deflector would be of great importance. The bottom of the rear/side deflector should be open so the water will drain quickly.

    Looking at most designs they leave the steering pedistal exposed to hits from the stern & beams (sides). I'm just wondering whether there are any cockpit designs out there that are safer & more bullet proof to such waves.

    Please send pics/links for any cockpits that might work out.

    Thanks,

    Joe
     
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  2. TeddyDiver
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    TeddyDiver Gollywobbler

    Center cockpits like HR's. Motorsailer style wheelhouses..
    Tiller.. ;)
     
  3. JosephT
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    JosephT Senior Member

    Hi Teddy, are you aware of any for racing yachts? Sorry I should have clarified. I'm aware of cruising yachts & motor cruisers with center cockpits. No doubt being down in a well drained cockpit would be a good idea...beats standing there and taking a monster wave smack on! :eek:

    In bad storms it's a good idea to have internal steering too. Reduce sail, heave to, steer from inside the cockpit. I recall one custom German circumnavigating yacht with internal steering. It had a nice plexiglass bubble that allowed viewing/riding out the storm from a safe spot.

    If this storm hit at night perhaps the crew wasn't ready for it & didn't see the wave.

    Either way I do feel the stern of these racing boats is a precarious spot in rough seas.
     
  4. michael pierzga
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    michael pierzga Senior Member

    You cant steer a boat in 8 meter waves from the inside. You must be outside, at the helm , with a crew standing watch next to you as wave spotter , calling the waves.

    If the steering pedestal collapsed then it was improperly engineered or installed.

    The pedestal should be massively strong.

    The hub of the steering wheel is the preferred attachment point for the helmsman's safety harness lanyard.



    The typical damage to a steering wheel is when the helmsman is thrown into it and the wheel bends or breaks.

    This can be avoided by installing crash bars to protect the wheel from helmsman impact.

    Always have a well designed, proven , emergency tiller on wheel steered boat. The tiller must be bolted to the rudder stock head to avoid nut round off as the tiller works.
     
  5. JosephT
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    JosephT Senior Member

    Michael, thanks for the items you point out. I concur a wave spotter is invaluable. Whether or not one was present and doing his/her job in this case is ???.

    To clarify my initial question though it is focused on the cockpit of this racing yacht. Let us take this scenario so I can make my point:

    Wave spotter: 30ft wave coming astern! Everyone knows this wave will hit the after steering wheel/pedestal and everyone on the back of the boat.

    Question: What type of structure would diffuse/deflect the force of such a wave?

    In a heavy storm waves can come from all directions so the aft end & sides of this particular cockpit is no doubt vulnerable.
     
  6. JosephT
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    JosephT Senior Member

    On further investigation it appears there has been some discussion on this topic. The term used to define waves coming from the stern is called "pooping seas" LOL.

    The yacht below has a nice low profile cage built around it and the steering wheel is dropped down inside it a bit.

    Perfecto

    [​IMG]

    Ref: http://www.nps.gov/maritime/nhl/adven.htm

    On top of this the hull on this boat has "fine, fast lines" and it would be ideal for a racing yacht in its day.

    I do like the cage look of this cockpit. It reminds me of UFC cage fights! If you're going to do battle with the ocean in a storm, at least this cage will offer you up a good chance to hang in there & kick some a$$ on those waves!
     
  7. Stumble
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    Stumble Senior Member

    I would rather have a stern that lifts with the waves so you don't get the breaking water into the boat. And I doubt that well can drain water fast enough to be safe. First wave adds four tons of water to the boat, second wave sinks it is not a good design concept.
     
  8. JosephT
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    JosephT Senior Member

    Most sterns are going to lift nicely. The point here is to diffuse the impact of a huge wave. That cockpit looks well drained to me. Most recessed cockpits have large drain ports. Looking strictly from the perspective of battling huge waves in a storm (45 to 70kt winds the Clipper boat had), a cockpit cage like this would be a tremendous asset. It would significantly reduce the impact of a direct hit by a huge wave. That's the ticket.

    Other open cockpit designs are inferior in this regard. If you focus on the key requirement to diffuse a huge wave then something like this will do it.

    At the end of the day all the other open designs are window dressing. It's your forearms and the steering wheel/pedestal vs. several tons of water.

    Game over.
     
  9. Stumble
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    Stumble Senior Member

    Joseph,

    You are assuming that the only thing a transom needs to do is provide protection from crashing waves. If this is your sole design criteria well this might be reasonable, but as with most things in boat design there are trade offs to a design like this.

    As I mentioned before the self draining aspect is a problem. Even with large cockpit scuppers closely spaced waves may not allow the enclosure to drain fast enough, which would add tremendously to the weight of water on the boat. Figure as a minimum safety issue you need to be able to drain the entire cockpit in 20seconds, and work out the size of drains necessary, most installed scuppers can't come close.

    Secondly, by creating a high projection from the deck you force crew to climb over the coming to enter or exit the cockpit. This may be a problem for less agile crew in the best of times, and during a storm could exacerbate someone falling overboard.

    Third, the additional windage and weight will negatively effect performance.

    This is just to name a few issues off the top of my head. Though, if this was such a critical design issue, why is it that all of the fleets that actually sail long distances in the worlds worst conditions have all moved to open transoms? To me I think you are looking at a single freak accident and designing to prevent a highly unlikely problem, at the expense of routine usability issues, and other safety concerns.
     
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  10. Stumble
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    Stumble Senior Member

    As an addendum, if the cockpit there is 10' across and 4' deep, which looks like a reasonable assumption based upon the picture, it would hold roughly 78,500lbs of water, or 9,400 gallons. To drain this volume of water in 20 seconds would take a cockpit drain 2.5 foot in diamater draining from the floor, those 3/4 inch cockpit drains ORC requires couldn't hope to keep up.
     
  11. CatBuilder

    CatBuilder Previous Member

    I'd have to agree with Stumble here and also want to point out that it wasn't a "big" wave that pooped the boat.

    It was a "steep" wave. A big wave you would just ride up and over. Only a very steep wave would get water over the stern. A sort of freak wave or a combination of two waves meeting and making one of those walls of water that appear out of nowhere.
     
  12. BATAAN
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    BATAAN Senior Member

    On the stricken vessel, note the transom details, in that a great deal of it slants inwards, it has a strong reverse rake (to extend the waterline and gain speed) with cut out middle with ladder and step, and forms a 'shovel' that directs all that water up and onto the deck.
    This is common type of 'sugar scoop stern' and not the first time one has scooped a sea that overtook the boat.
    Many times I have been in bad breaking conditions going downwind with the stern shown in the enclosed picture and every time (so far) one of those monsters overtakes us as a breaker, the aft-raking, fat stern lifts like an elevator, the boat accelerates and somehow the water never breaks aboard.
    This includes at least 4 very bad gales, one that went on for 3 days with chaotic seas at times, estimated at over 5 meters and almost all breaking.
    English channel ketches and schooners typically had the half-round wheelhouse shown in the second plan and pictures, since they were often operated overloaded with bricks or other very heavy cargoes and were quite subject to being boarded with winter, English channel seas.
    Some features of modern racing sailing craft are strictly for engineering speed, and detract from seaworthiness, and I think this incident shows that.
    The idea is not so much to deflect the wave, but to keep it off the deck in the first place and more reserve buoyancy that increases greatly with immersion will help keep the boat above the fray. Unfortunately this lengthens the deck and shortens the waterline, exactly what you don't want in a racing boat.
    When racing, boats are pushed very hard and chances are taken and sometimes this is the result, no matter what the design.
     

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  13. MikeJohns
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    MikeJohns Senior Member

    It's a feature of the designs that they offer no protection on deck and waves sweeping the decks have often injured the crew on larger racing sailboats. It's been quite common.
     
  14. JosephT
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    JosephT Senior Member

    Thanks for all the good feedback, especially the info on the pilot houses. All in all the flat deck & 'sugar scoop" stern' will work out most of the time on these racing hulls. It's a matter of avoiding certain situations like this "steep wave" at all costs. If you're luck runs out...well...you play you pay.

    I was also checking out some sailing suits with some armor/padding inserts. This one looks like it would protect the kidneys/ribs & legs pretty well.

    http://www.myboatsgear.com/mbg/product.asp?prodID=2219

    I'll be doing this race next year so I want to study this situation well and gear up.
     

  15. CatBuilder

    CatBuilder Previous Member

    IMO, the best protection is available on a multihull and that is the type of protection I am putting on mine:

    A forward cockpit (just aft of the mast) that you may steer from. The best part is a deep well and no reason to ever get up on deck and do the "walk of death" from the stern to the bow.

    I realize this is only available on multihulls at the moment, but IMO, it's the safest cockpit there is - especially for freakishly steep waves trying to board the stern.


    [​IMG]
     
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