Edson Simplex steering gear

Discussion in 'Metal Boat Building' started by pdwiley, Dec 30, 2010.

  1. pdwiley
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    pdwiley Senior Member

    It's a bit of a toss-up if this thread belongs here or somewhere else but as I'm building a steel Colvin design boat, here will do.

    Tom specifies Edson Simplex worm steering gear for the boat. The current Australian price for the OO size specified is $8200 which in my opinion as a machinist is so far beyond reasonable as to be risible.

    OTOH I do like the concept and would like to have this type of steering gear. So, I'll build my own. I've got the catalog pictures and some of the dimensions as well but better photos and a few more dimensions would save me some time doing drawings.

    Does anyone have a boat with Simplex steering gear or pictures of it? If so could they please post them here? Thanks. I've added a couple of pix to show what I'm talking about and the dimensions I've already got.
     

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  2. gonzo
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    gonzo Senior Member

    The cheapest option is to use an automotive steering gear.
     
  3. FAST FRED
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    FAST FRED Senior Member

    All the worm steering gears do not have feedback. They will hold whatever helm you crank , but there is no "feel".

    If this is desired a simple Hyd unit will do just what you need.

    Personally cable steering with LARGE radiused shives or a lever setup works better if its a sailing boat.

    Tho not as "nautical" the mechanical steering from a bus or large truck would be the $200 choice that would still last almost forever.

    Spend the $8000 saved on a CPP .

    FF
     
  4. gonzo
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    gonzo Senior Member

    No offence, but I would spend the savings on beer.
     
  5. pdwiley
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    pdwiley Senior Member

    I know about the lack of feedback, not a problem on a cruising hull IMO.

    Simple, hydraulic and cheap is dubious. I know you didn't say cheap but why should I spend money on hydraulics when I don't really like it?

    Cable and sheaves is my fallback solution. I could use a truck steering box and I may but at the moment I've got my hands on a suitable 2 TPI LH threaded shaft and I've machined the nut to suit. Total cost to date $50 and a few hours of entertainment running my lathe & milling machine.

    If I could buy a CPP for a 20HP engine I would, probably. Sabb stopped making those engines years ago and nobody else does. If I have the money left over at the end of the build I'll probably buy an adjustable pitch prop. I know it's not the same or even close but my understanding is, they're better than a fixed prop for less drag and also power in reverse.

    Seems nobody has pix of the Edson gear, no problems. I found a set for sale on Ebay but it's the big size and the vendor only ships to the 48 contiguous states, so - who knows. I've emailed them about shipping.

    PDW
     
  6. FAST FRED
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    FAST FRED Senior Member

    One consideration will be how to disconnect the steering gear so a self steering gear can work in very light air.

    The std Edison would be almost impossible to disconnect , a truck mechanical would simply require a pin pulled, the Hyd a cable operated by pass valve simply opened or closed.

    Today the Auto Pilot and SS gear should be thought of as a system , right from the design stage , to have the lowest cost , best chance of operating and be repairable worldwide .

    CUSTOM anything is not taking good advantage of the world wide sources for existing gear.

    Perhaps on an exotic racing Cup boat there is no choice , but for a stock cruising boat?

    "If I have the money left over at the end of the build I'll probably buy an adjustable pitch prop. I know it's not the same or even close but my understanding is, they're better than a fixed prop for less drag and also power in reverse."

    IF your boat has deadwood holding the prop shaft , the best compromise is a better 2 blade prop.

    The usual "sailing prop" has very narrow blades and does a poor job of putting thrust into the water, fwd or reverse..

    A 2 blade that has blades as large as would be found of a normal 3 blade power boat prop WILL put the power into the water , more efficiently than a folding prop (smaller hub) or a 3 blade cruising prop (less induced drag).

    Happily the wide 2 blade can cruise with a prop lock, locked behind the deadwood with almost no losses.

    There will be no blade or form drag , just the drag of the surface area, small.

    Tweaking at your most common sailing speed is DANGEROUS , but consists of 2 opposing pipe wrenches to allow the spot on the shaft to be marked where the prop is not trying to spin in either direction.

    Tom Colvin lives only a few miles from our place and he is a really nice fellow.There have been many complaints of his choosing a way way too small engine for his cruisers years ago.. The modern concept of 3hp per ton will keep you out of trouble in terms of operating speeds and the house loads ,alternators.



    FF
     
  7. pdwiley
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    pdwiley Senior Member

    I agree that custom gear is generally undesirable but when the price of off the shelf equipment vastly exceeds the cost to manufacture then there's been a breakdown in the economies of scale or the manufacturer is attempting to exploit monopoly pricing.

    I can't see any good way to hook up self-steering to the rudder system as designed regardless of steering gear as it terminates below deck. I have some thoughts on those lines but it's a different problem. According to Tom these hulls are well balanced and require no wind vane steering gear anyway. Perhaps for him and not for me, we shall see...

    Autopilot should be simple to attach to an Edson type gear.

    WRT propellors I wasn't referring to those 2 blade folding sailboat props but something like an Autostream prop. These feather but also deliver full thrust in fwd and reverse. Not cheap.

    As for engines I have a 30HP Yanmar for a 7 tonne boat.

    I've been corresponding with Tom for years, he's always been courteous and helpful even in the face of some pretty stupid questions. There have been a lot of these hulls built, I'm trying to keep mine as close as possible to the design.

    PDW
     
  8. FAST FRED
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    FAST FRED Senior Member

    The best self steering to me is the Aires.

    When the vessel stern is tossed off course by a wave , the paddle gets forced in the proper direction to correct , even before the wind portion notices.

    Upwind most anything works , down wind in big waves with light air is the hassle that requires good gear , or you hand steer , and contemplate the cash saved.

    The WIDE BLADE 2 blade prop does what the $20X more expensive high maint. props do BETTER in terms of powering,as well as offering lower drag if indexed properly.

    Another advantage is different engine combos in a boat have different "sweet spots" , changing out a solid 2 blade will cost less than the postage to return a complex prop for another try.

    7 Tonnes 30 rated hp, should be fine.This is small enough to use a lift type muffler , the only sound you will hear is like someone taking a tinkle overboard from the cooling water!

    Probably 1/2 gph at normal cruise , (SL 1.15) depending on prop and accessories.
     
  9. michael pierzga
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    michael pierzga Senior Member

    One advantage of hydraulic steering...beside being cheap and easy to install...is the ease of interfacing an autopilot. You should consider hydraulic steering. A prop shaft belt driven hydraulic oil pump is one of the most reliable autopilot energy systems that I know of. Electric motor powered autopilots have a short service life. Remember that the prime job of an autopilot is to drive the yacht when motoring.

    Im not familiar with Autostream props but I have 35 years worth of experience with MAX props...very good props. Be sure to compare features and price between the two props. The Max props weak point is that it blows grease, so must be repacked every year. Autostream says they have addressed this problem with O rings.
     
  10. pdwiley
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    pdwiley Senior Member

    The Autostream props can easily have their pitch adjusted, even in the water, by the owner and different pitch set for fwd & reverse. The blades feather so minimal drag. Drawbacks, complicated & expensive.

    I can't see getting, locally, a 2 blade prop in say 22" dia by 18" pitch for $175 which is 1/20 of the price of an Autostream prop. If you can get one for that price please allow me to send you the money via PayPal or a postal money order, and send me one. I'm serious providing freight isn't a killer.

    Micheal, WRT hydraulics, this is a simple sailboat, I do not want to run the main engine just so I can have a hydraulic autopilot. And 'cheap' is relative WRT steering, I can build almost anything I want myself but only do so when the savings in dollars is worth the time invested. The Edson steering gear clearly falls into this category so I build my own or use an alternative. How much is a hydraulic steering system suitable for a 12m 7 tonne displacement cruising sailboat?

    PDW
     
  11. michael pierzga
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    michael pierzga Senior Member

    Should be simple to fabricate the Edson steering gear. Im surprised it was so expensive.

    Oh and Hydraulic autopilots are always electro hydraulic. Prop shaft driven when motoring and electro motor hydraulic pump when sailing. Its a very common setup, even on smaller boats. The Mini Transat single handers favoured hydralic auto's for a long time because of their robostness. .

    On problem with being way down under in Tasmania it that you are along way from the "yacht breaker" yards. Many yachts are destroyed each year...fire sinking whatever. These gold platers have mountains of gold plated gear. The stuff like steering gear, rigging, anchor windlass's, ss pulpits, winches, props, ........... all sold at cents on the dollar. Insurance companies are the contact...keep your eyes open as you build.

    Normally a boat sailing with a feathering prop carries two...a cheap fixed blade and the fancy, costs as much as your car, feathering. Props are easy to damage...ding them on a piece of floating junk. A fixed prop is simple to repair on a workbench...the feathering has to be sent off for remanufacture. Ive sailed many miles with a fixed prop fitted because the feathering was off for repaires. Might be best to start off with the fixed and put the feathering on your "eyes like searchlights " , thats a great deal.... wish list.
     

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  12. pdwiley
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    pdwiley Senior Member

    You & me both. Price in the USA seems to be around $3500. Add import duty, GST and local distributor's margin (I estimate 100% markup for placing an order) and you get the local price - and no sale. I've got the screw & nut done, pretty much, next the link arms and attachment plates on the rudder stock. Not difficult and no really close tolerance machining, I'm just making the dimensions up more or less as I go along, loosely based on the Edson drawings.

    Little to no source of used parts locally.

    I have a 3 blade fixed prop already that's my fallback unit. It'll depend on available funds for one of the Maxprop or Autostream types. And haunting Ebay of course.

    I also have a collection of Bimba pneumatic double-acting cylinders and it occurred to me that they might make useful light duty hydraulic rams. Not sure if I want to go to the trouble though as it still leaves the pump and other bits. Easier to simply go to cable steering system. I may end up doing that anyway.

    PDW
     
  13. michael pierzga
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    michael pierzga Senior Member

    Cable steering is cheap and effective. Perhaps have a swing by your local agricultural machinery, tractor repair shop. Tractors have worm drives, bevel boxes, drag links...might be usable components for a yacht steering system.
     

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  14. FAST FRED
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    FAST FRED Senior Member

    "Cable steering is cheap and effective."

    Even if great over sized shives and bronze wire rope are purchased from Edison , it has great sailing feel and not that costly.

    A whip staff (vertical lever as tiller) can be located in a pilot house or where ever the steering will be done.

    The whip staff takes almost zero room and could easily be un shipped from a simple socket,and cables do not fight the self steering very much if properly sized.

    Best of all a few hundred bucks will purchase a tiller auto pilot that will be quite happy to push pull on the whip staff .
    These are about 1/3 the cost of a wheel autopilot, so a few spare could be on board at little cost .

    There are also 2 types of Hyd steering , one where an engine provides the power , and the steering input can be a small knob , tiny lever, or autopilot solenoids .

    The other is cheaper , wheel is attached to a rotary pump , you are the energy and the cylinders move the rudder. The downfall here is a power hog Hyd pump DC is needed for the AP.

    I have seen attempts too use a tiller pilot attached to the wheel.

    These mostly fail as the AP is now supplying the force to pump the fluid , but worst of all the L/R pumping action is never consistant enough to maintain a center.
    For a quickie hoisting the sails leaving harbor , or an afternoon sail with constant monitoring it does work.
    For a serious cruising boat , it doesn't.

    Why not purchase direct from Edison, and have it shipped?

    FF
     

  15. pdwiley
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    pdwiley Senior Member

    As they have a local distributor they may not sell direct. I've struck this with companies in the USA in the past. It's not my main objection, however.

    It still comes to over $4000 which IMO is ridiculous. They are lovely bronze castings and the machining is probably wonderful but as a piece of technology, come on.

    I haven't looked for commercial square threaded rod but I know I can buy ACME threaded rod & nuts; in any case I could thread-mill that square thread out of a piece of 303 stainless in an hour once I set the mill up. It'd take me longer to set up the gear train on the table power feed than it would to mill the thread. The flange on top of the rudder stock can be easily made from a $30 Fenner Taperlock flange & bushing, I bought one this morning. The turning plates on top of the flange can be made from anything from 6061-T6 to 1020 hot rolled painted steel, bronze bush the holes. The link arms cut from some 16mm plate with the holes bored. Probably less than $300 in total in materials. Maybe 3 days of work if I wasn't trying hard.

    These days I don't earn $1500 a day and I don't want to go back to software consulting interstate to get it either.

    Cable steering is an alternative and Tom did provide drawings for such a unit. Fabricating those parts is trivial. I'm amusing myself building the Edson type steering gear at the moment but I will easily be able to swap systems by simply unbolting the top plates etc from the flange mounted to the rudder stock. In fact I can make an emergency steering unit that would bolt on in place.

    I don't know what you mean by oversized sheaves but I personally wouldn't use less than 20:1 diameter ratio sheaves so for a 6mm cable that's a 120mm diameter sheave. I spent a lot of time with scientific equipment etc on wires over the side of a ship and it doesn't pay to reduce your sheave sizes to the point where you're work-hardening your wire. Murphy's Law ensures it'll break at the worst time...

    I know nothing at all about hydraulic steering systems or autopilots so am happy to be pointed in the direction of useful information.

    PDW
     
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