DIY rudder fittings

Discussion in 'Sailboats' started by Andy, Dec 7, 2007.

  1. Andy
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    Andy Senior Member

    Has anyone ever built themselves some rudder fittings? I was pricing pintles and gudgeons for my FD and they come in at £100 ($200)...I have it in my mind to laminate up some carbon straps (4mm thick) with a bulge in the middle to accept a 'cast' epoxy/graphite powder piece which would be drilled out. The straps would be through bolted to the transom, and the rudder would have a similar fitting at the top and bottom of the stock. Id then run a long stainless pin through the lot to hold the rudder to the boat. Any thoughts anyone? :?:
     
  2. PAR
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    PAR Yacht Designer/Builder

    I'd hate to lose my steering gear with a cobbled up set of hardware.

    Yep, the cost can bite. Try running down to the local welding shop and have some straps (S.S.) bent up to suit your needs, it'll be a lot cheaper. Make the holes (welded on section of pipe for the gudgeons) for the pintails fairly over size and insert a HDPE or other high density, self lubricating plastic dowel into it (real tight fit), then drill out for a sweet fit for the pintal. It'll serve as a bearing and keep chatter down too.

    If you want real low budget, you can use a few hook eyes and some well sized bolts, in a pinch.
     
  3. astevo
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    astevo Junior Member

    i had some carbon ones on my moth, couldnt justify putting big stainless ones on somehting that i tried so hard to keep light.
    laminate the piece with extra meat around the bearing area, and either drill out to acept a nylon/delrin bush or let the pin bear straight on the carbon
     
  4. Landlubber
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    Landlubber Senior Member

    Just a word of advice about using nylon as a bushing, it is hydroscopic, it absorbs water, so do not make the pintles fit perfectly, or they will jam up in use. Allow a few thou clearence and all is fine.
     
  5. alan white
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    alan white Senior Member

    For what it's worth, adding to PAR's comment, every time I need a fitting (and the last few have been a whole set of bowsprit fittings), I buy or salvage the stock (usu. 316 ss), shape/bend/drill each piece carefully, and clamp them to a suitable welding jig in exact position, and then and only then deliver them to a guy named Greg who is the best TIG welder I know.
    He then hands back to me something that, when polished, looks and works like a very expensive store-bought fitting.
    Cost? Maybe $5.00 a piece. Why? Because welding alone---- just running bead---- takes very little time.
    Because welding alone is the thing requiring true talent. Set-up is only technique. You can pause and repeat operations, slow down, adjust, stop, mull over, etc., but welding is a commitment, a one-shot deal.
    You need a good vise, a drill press, a 4" angle grinder, files, (and with aluminum a table saw and a router), and an understanding of cross-sectional analysis to determine tensile strength (very simple using a materials book and a calculator).
    It's amazing what you can do if you have the tools and knowhow to prepare parts for a good welder. You will save huge money if you aquire those skills.


    Alan
     
  6. Landlubber
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    Landlubber Senior Member

    OK Alan, If we are going down that lane, may I suggest that the builder also purchases those sponge abrasive discs for 4" grinders and polishing felts. The sponge discs are remarkable at getting rid of the flows in the welds, the felt discs and the wax sticks finish off the job.

    As Alan says, the end result is "just like a bought one".
     
  7. PAR
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    PAR Yacht Designer/Builder

    I'm like Alan, in that I usually make up fitting when I can, to save money over store bought. These pieces are often stouter then mass produced, fit better, can be application specific and can have a custom touch, like a boat's name or builder's logo etched into it.

    A lot of people don't know how to work metal and stainless can be intimating. Use the best and sharpest drill bits you have. Work the material slowly into bends. You can make up just about every piece you need for a small cruiser.

    I too, (like Alan) have a real fine welder locally, who permits me to bring my jigged up stuff over in a box. When he gets a chance, he opens the box, throws a few beads and I'm good to go.

    I've invented some pretty clever fittings over the years, most would have been quite costly, if I'd had them do all the fabrication work, to a set of plans.

    On a typical pintail and gudgeon set, you'd need 4 beads per pair, so 8 total beads, maybe an 1 1/2" long each. This literally takes a good welder, just a minute or so to perform. That's not much labor to pay for. Of course, most shops have a minimum rate, so bring a box of "goodies" and let them charge you for an hour's efforts.
     
  8. alan white
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    alan white Senior Member

    Stainless is relatively easy to work. It works much like carbon steel. One difference is the difficulty in drilling. Counterintuitively, the way to drill it, once a sharp bit is chucked into the press, is to use a LOT of pressure rather than moderate pressure. If the bit isn't cutting a spiral peel out, it's heating up---- and once it reaches a threshold temperature, the bit melts. Better to push hard, using plenty of lube, and when the lube begins to smoke, stop and wait. When the temp goes back down, go for it again. I haven't melted a bit in years (though before that, I melted plenty).
    Stainless takes to filing and sanding as well as carbon steel too.
    For some reason, Marine fittings are crazy expensive, enough to make me laugh sometimes (or ask the clerk to scan it--- maybe there was a mistake).
    A typical example is a small 1/2" x 16 ga. x 4" flat tang with a hole at each end, selling for $10.00. This is the easiest thing you could make using 10 cents worth of sheet metal. In fact it probably costs 25 cents to manufacture.
    Some things we've gotta buy. But isn't it great that we can make fittings and parts that are actually better (cause they're custom designed) than the store-bought stuff.
    I've machined aluminum using carbide woodworking tools too. Marine grade aluminum is strong as hell, and won't corrode easily. Great for all kinds of parts.

    A.
     
  9. gggGuest
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    gggGuest ...

    Yes its quite possible. I've done it a few times. The big caveat is that you have to design carbon fibre rudder fittings, just making an imitation of metal ones won't be successful. I usually use pultruded glass tube with the same inside diameter as the outside diameter of the metal pin as a bass for the bearing.

    http://www.sailingsource.com/cherub/rudstock.htm
    http://www.sailingsource.com/cherub/fitout.htm#gantry
     
  10. rob denney
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    rob denney Senior Member

    G'day,

    I am amazed that anyone is still using heavy metal and bolts on lightweight boats (and heavy weight ones for that matter). Carbon and glass are much easier to use, don't need special equipment, don't corrode, don't leak and can be made as strong as you like. They are also light, cost almost nothing and if you are the experimental type, can be ground off and rebuilt very easily. If you use tow (the individual bundles of filaments that are used to weave the cloth), then it is even cheaper and easier.

    Where metal is good is in wear resistance, so use a round ss pin to join the rudder to the boat. Pultruded glass is lighter but hard to get in short lengths. The gudgeon on the boat will work best if the carbon or glass is passed through holes in the stern and stuck to a fore and aft bulkhead. If this is not possible, put a block of timber in there and pass the tow through a hole ion the transom, round the block, back through the transom and round the pin which should have a wrap or two of plastic packing tape on it to give a clearance fit. Make sure the pin is vertical and held away from the transom by say 12mm/1/2". Fill the space between the pin and the transom with high density bog and when all is cured, knock the pin out, sand it smooth and you have your fitting. Same at the top and on the rudder.

    An hours work for the first one, twenty minutes for the last one.

    If this is not clear, ask some questions and/or and I will draw you a picture.

    regards,

    Rob
     
  11. granite
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    granite Junior Member

    When I make carbon rudder fittings I usually make glass bushings by wraping glass tape around the ss pin, sutably waxed they will come off and can then be cut into the short lengths required.

    If you do the layup of the fittings on the rudder and boat with the pin in position they will be perfectly aligned, something that is difficult to do with a drill.
     
  12. Andy
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    Andy Senior Member

    Great responses all. I'll knock up some technical drawings this week and post what I'm thinking of. The more I look at deck hardware, the more I baulk at the cost and complexity of it all. I think this is a great place for discussing cheap, elegant alternatives. :idea:
     
  13. Petros
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    Petros Senior Member

    I made nearly all of the hardware for a 14 foot sloop I built last summer. I used salvaged scrap metal, a drill press, a file and sand paper. All of the lumber was salvaged over the last few years as well, I had very little cost into the hull.

    One thing to keep in mind on the rudder fittings, the loads can be quite large, and they are easy to damage if the rudder hits something. It is impossible to control a sail boat without a rudder, so make sure it is strong enough.

    The carbon composite sounds simple enough, just make sure you have more than enough strength, overbuilding it would add only a few ounces of weight.
     
  14. Landlubber
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    Landlubber Senior Member

    Petros,

    Don't wish to get into an argument here with you, but sailboats have sailed many thousands of miles without rudders in emergency situations, it is all a balance of the boat and sails....rudders just make it very convenient to do the final adjustments on a well set up sailboat
     

  15. Petros
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    Petros Senior Member

    That might be true of many sailboats, but when mine failed on my 14 foot sloop, it was quite an ordeal until I got something temporarily rigged to get us back to the beach.

    We were only a little ways out from Port Townend WA, I was just getting it up on plane when I sheared the rudder mount off (I had miss-underestimated the loads on the rudder). And the wind off the Strait of Jaun de Fuca were pushing out into the shipping lanes and into some of the roughest water in Puget Sound. Not exactly how I wanted the maiden voyage of my little sailboat to end up.

    Live and learn, I will not make that mistake again.
     
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