Best material oarlocks / sockets for rowing a polethylene dinghy

Discussion in 'Materials' started by amspioner, Oct 6, 2017.

  1. amspioner
    Joined: Oct 2017
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    Location: Amsterdam

    amspioner New Member

    Hi all,

    Maybe somebody can advise me.

    I own a pioner 12, a small dinghy (material is polyethylene, weight 105kg, size 352 cm x 142 cm), which I want to use by rowing only - no motor. It came with plastic oarlocks and sockets, but they are no good, they bend and don't turn smoothly. I want to change them for better ones. I have not much experience with rowing and no experience with boat materials at all. I will row with sturdy aluminium oars (220 x 5 cm).

    What material would be best to change the oarlock and sockets into? Aluminium, bronze, messing, steel, chrome, better kind of plastic?
    Any other helpful properties beside the material that make up for good oarlocks? Also, what is the ideal inner oarlock diameter for oars with a diameter of 5cm?

    Preferably, they shouldn't be overly expensive, I won't be in professional rowing competitions ;)
    but I would like them to turn smoothly and will use them every other day
     
  2. PAR
    Joined: Nov 2003
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    Location: Eustis, FL

    PAR Yacht Designer/Builder

    Welcome to the forum.

    A good set of locks shouldn't be hard to find and price is a fair indication, but generally you'll want a similar material as the oar and/or hull shell to avoid dissimilar materials issues (corrosion). The real problem will be attachment on the polypropylene hull shell/deck cap. Not much sticks to this stuff, so some sort of mechanical (screws, bolts, etc.) will likely be necessary. Polypropylene doesn't hold fasteners well, in the thicknesses commonly employed in the hull shell. Consider a sandwich with something that can grab the fasteners.
     
  3. amspioner
    Joined: Oct 2017
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    amspioner New Member

    Thank you for your reply,PAR! I discovered metal screw holes available under the current plastic oarlock sockets, so the attachment will be fine. I am just really unsure which material to choose for the locks and sockets. Indeed they probably best be of the same material, but am still unsure whether to get aluminum, bronze, chrome, steel etc.... Or does it not matter much for the rowing experience?
     
  4. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    No it doesn't matter for the rowing experence, but long term, you'll want a similar material. Locks have to tolerate a great deal of strain and the typical sheet metal screws, they use to attach things to a polypropylene hull, just don't have enough "meat" to keep things in place. Maybe you can post an image of where these puppies will live.
     
  5. amspioner
    Joined: Oct 2017
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    amspioner New Member

    I made some pictures this week but it was dark when I took them. I hope you can see well enough. Otherwise I will be able to take new ones tomorrow. The plastic oarlock socket is still on the boat in the first picture. Then follows a picture with the metal screw holes and lastly a picture with a plastic tube in which the socket was placed that goes into the big center hole of the second picture. I needed to know the measures of everything so most pics will show my measuring tape.

    Let me know if I should take better pictures :)


    IMG_20171004_192254.jpg IMG_20171004_194242.jpg IMG_20171004_201201.jpg
     
  6. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    Yeah, it looks like they've cast or possibly bonded in some "nutserts" which are a threaded rivet sort of thing. Give it a try, the worst that can happen is the lock will rip out of the hull shell.
     
  7. Ike
    Joined: Apr 2006
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    Ike Senior Member

    You can get aluminum oarlocks. I have seen them from as little as $10.00 (I would avoid those) up to over $100.00. So a quick online search will find what you are looking for. I use bronze but you don't need anything like that for a poly boat. Put a little vasoline on the shafts. It will keep them from binding and squeaking. If you don't want a petroleum product use a vegetable oil. Mine have nylon bushings that fit in the sockets and prevents metal to metal contact.
     
  8. Mr Efficiency
    Joined: Oct 2010
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    Mr Efficiency Senior Member

    Does hot glue have any sort of adhesion to polyethylene ? It is polyethylene itself.
     

  9. amspioner
    Joined: Oct 2017
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    Location: Amsterdam

    amspioner New Member

    @PAR, @Ike & @Mr Efficiency,

    Thank you all for your responses, really great! Had some work issues which made me forget about my nice little boat and this forum, but am gonna try to find the right size aluminium oarlocks and socket this weekend. I did see some bronze ones for not too much money as well, would love the contrast of the fanciness of that material to the rest of the boat, just for fun. So far, this morning I had trouble to find the right size between the screw holes and the correct size of the socket diameter (often they are not specified in the webshops). Thanks for the suggestions!
    @Mr Efficiency let's hope the screws stay put and glue isn't necessary ;) If it comes to problems like that, I will be back here to repeat your question ;)
     
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