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ferrocement-oars

Home Forums Research Engineering ferrocement-oars

This topic contains 9 replies, has 4 voices, and was last updated by Avatar of elspru elspru 2 years, 12 months ago.

Viewing 10 posts - 1 through 10 (of 10 total)
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  • #1487
    Avatar of elspru
    elspru
    Participant

    since we like ferrocement so much,

    and I need an oar to use by dinghy,

    I decided to make a ferrocement oar.

    here is a picture of the rebar frame

    here is a close up of the paddle.

    it’s interesting in that can have a much larger paddle,

    and considering how oars are usually used sideways, makes sense to have the paddle pointed sideways.

    also thats as much as I could bend it even with heavy duty gloves and croc shoes.

    how many layers of galvinized 1″ chicken wire to use?

    also does the handle need chicken wire or can it take concrete by itself?

    I’m wondering about the potential of having a spoon shaped paddle to maximize gathered water hmmm.

    #13287
    Avatar of elspru
    elspru
    Participant

    double post

    #13294
    Avatar of OCEANOPOLIS
    OCEANOPOLIS
    Participant

    would you make a ferrocement oar? Why only one and not a pair?? Regardless, there is a very good reason that oars are made of wood or plastic, and nothing else. Besides the fact that they should be light and strong in the same time (for the obvious reason), they should also FLOAT. Any oar in existence today has that quality,…Ferocement oars don’t float. If you drop them in the water and they don’t float (and oars have a tendency to just fall in the water,…for centuries) down to the bottom they go. Now you are in a “oarless” dinghy, somewhere out there on the water, in the middle of nowhere. What’s next?

    #13295
    Avatar of J.L.-Frusha
    J.L.-Frusha
    Participant

    Rowing with one oar would approximate circles, in still air/water conditions…

    Another thing, cement won’t take the constant abrasion that other, better-suited materials will.

    Later,

    J.L.F.

    Never be afraid to try something new…

    Remember, amateurs built the ark, professionals built the Titanic.

    #13297
    Avatar of elspru
    elspru
    Participant

    OCEANOPOLIS wrote:

    would you make a ferrocement oar? Why only one and not a pair??

    J.L. wrote:

    Rowing with one oar would approximate circles, in still air/water conditions…

    Canoes can be rowed with a single oar just fine…

    It’s all about the technique really.

    though of course I could make more oars,

    may as well start with one.

    Regardless, there is a very good reason that oars are made of wood or plastic, and nothing else. Besides the fact that they should be light and strong in the same time (for the obvious reason), they should also FLOAT. Any oar in existence today has that quality,…Ferocement oars don’t float. If you drop them in the water and they don’t float (and oars have a tendency to just fall in the water,…for centuries) down to the bottom they go. Now you are in a “oarless” dinghy, somewhere out there on the water, in the middle of nowhere. What’s next?

    can simply attach the oar by a string to the dinghy, or to a float, or both.

    J.L. wrote:

    Another thing, cement won’t take the constant abrasion that other, better-suited materials will.

    what kind of abrasion are you refering to? water rushing over it?

    wooden oars have a tendency of braking easily, and plastic oars are weak.

    I’m fairly sure a ferrocement oar can handle pushing off from the shore,

    especially considering the inherant springiness of it’s design.

    Also I’m fairly certain it would fare better at rowing through thin ice than wooden equivalent.

    If there really is excess abbrasion at the tip, can simply apply an epoxy cement mix, or other strong cement variation.

    calm aware desire choice love express intuit move

    #13305
    Avatar of J.L.-Frusha
    J.L.-Frusha
    Participant

    Actually, I was thinking of when it hits the lip of the sides and/or oar-locks…

    Later,

    J.L.F.

    Never be afraid to try something new…

    Remember, amateurs built the ark, professionals built the Titanic.

    #13308
    Avatar of elspru
    elspru
    Participant

    J.L. wrote:

    Actually, I was thinking of when it hits the lip of the sides and/or oar-locks…

    can put a plastic sheath or bracelet at such locations, perhaps via ductape or plastic pipe.

    been actually thinking of perhaps putting on one of those pool noodles on the stem of the oar, they have holes in the center anyhow.

    then it would float, potentially even act as a floatation device for a person holding the oar.

    calm aware desire choice love express intuit move

    #13315
    Avatar of elspru
    elspru
    Participant

    applied mesh to the oar today, I used a piece 6ft by 4ft, it’s a moderately heavy oar now.

    likely only way it’ll be usable is if I have a high proprotion of loose foam as aggregate.

    it may be too much mesh also, perhaps I’ll take some off.

    I’ll be on the lookout for cheap oars also,

    for comparison trials at the least.

    calm aware desire choice love express intuit move

    #13317
    Avatar of shredder7753
    shredder7753
    Participant

    you need a handle at the top. find two heavy rocks or a tree that has a split trunk, stick the top 6″ inside and pull hard on it. without a handle at the top theres no way you can use the oar.

    ____________

    My work

    “Leadership and do-ership are not the same thing”

    #13319
    Avatar of elspru
    elspru
    Participant

    shredder7753 wrote:

    you need a handle at the top. find two heavy rocks or a tree that has a split trunk, stick the top 6″ inside and pull hard on it. without a handle at the top theres no way you can use the oar.

    That’s actually what I already did yesterday. If you look in the picture you’ll notice a fairly visible bend at the end of the oar.

    I couldn’t find any loose foam or anything to use as an aggregate. someone suggested perlite, but that sucks up water so is no good.

    got an oar kit today, with aluminimum handle and plastic paddles, it can assemble into two short oars, two long oars, or a kayak oar. $40

    I might still be able to use this ferrocement, perhaps repurposed as a tiller.

    calm aware desire choice love express intuit move

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