Oarlock material question

[Nanoose]

At the risk of being branded a heretic...would it be bad to use cast iron as an oarlock material? Nanoose has some pretty large oars; they were the original auxiliary power until a previous owner put in a small inboard (volvo 7hp). A friend of mine is an amateur blacksmith and said he could make me a pair pretty easily out of cast iron. I don't really want to a.) build a forge and cast my own or b.) pay a gazillion dollars to have them made. The oarlocks would not be permanently mounted but only when needed. My concern is that the material would be too brittle...

Thanks for your advice!

Dave

http://www.imagestation.com/picture/sraid220/p8493099c3abf7a62e2244f0ffd5ee874/ebb2e0e3.jpg

[Bob Cleek]

Galvanized castings are used regularly for this purpose. Rusting may be an annoyance, but there are spray on galvanizing coatings that work fairly well. As for cast iron, there is cast iron and there is cast iron. If the metal is brittle, yes, there may be a problem. Experiment and see how it works out. Hard to imagine where you'd find store bought ones for oars that size!

On the other hand, if your friend has a foundry set up, why cast iron? Bronze melts at a lower temperature and the casting is exactly the same. You'd probably need a separate crucible for the bronze, but beyond that, it's six of one and half dozen of the other. Ask him to cast them out of bronze rather than iron!

[Bruce Hooke]

Do you really mean "cast iron" as in making a mold and pouring molten iron into it, or do you mean wrought iron, as in something a blacksmith makes by heating and hammering metal? Since you talked about I blacksmith I suspect you are talking about the latter.

[Thorne]

I agree with Bruce, seems like your average blacksmith would produce what is called "wrought iron" and is actually hammered / forged mild steel. Mild steel is very prone to rust as it has a lot of carbon, and might also fracture at the critical pin/horn joint.

For something that size, unless you plan on doing a lot of rowing, why not go the trad route and use either dual thole pins, or a single pin with a grommet?

No rust, no noise (compared to squeaky metal locks and bases), greatly reduced cost when compared to custom oarlocks, and the pins can be made removable so they don't have to be sticking up and catching lines all the time. Culler shows a removable thole pin with a lanyard/leash in his book...

If you don't like the dual pins or pin and grommet, you also can make oak "horns" for non-rotating oarlocks. These are made in two pieces which fit together into a slotted base -- so they are strong, removable and pretty! As seen below on my friend's boat _Holly Bough_, they can be rigged with lanyards so they don't fall overboard.

http://www.luckhardt.com/stnlgn2/stnlgn2-Images/14.jpg

[Tom Robb]

What Thorne said.
Quiet is good.
No rust & easy to replace if damaged or lost. Things ought to only be as complicated as necessary.

[Nanoose]

I believe wrought iron is more correct, sorry!

I like the aesthetics of the thole pins but the base and socket for the oarlock already exists and I think it would be simpler/easier to go with what is there.

Thorne, can you point me to a picture of that the "single pin and grommet" looks like? I'm not sure what that means.

Tom, agreed. Simpler is better. We sailed away for a year with no radar, watermaker, SSB, etc. and were able to stay out when others were having their systems repaired. I'm a believer.

Dave

[Thorne]

I'll keep searching, but it is basically a rope loop (aka grommet) tied onto a single thole pin. Opinion seems to differ as to whether you row with the grommet to the fore or the pin to the fore -- in other words whether you row onto the pin or the grommet.

You could consider drilling a hole for a thole pin in the oarlock block/riser/thingie, or replace the oarlock mounting plate (that goes into the hole) with just a hole for the thole pin. If you have side-mount oarlock brackets, this of course won't work...

Here is a boat with thole pins. Imagine the second pin replaced with a loop of line / grommet, through which the oar goes.
http://www.greatwoodboats.com/rowboats/images/crb06.jpg

Ah - I KNEW I could find it if I searched long enough. Here is the shallop being rowed, and you can see both methods (we teased them about it) -

http://i45.photobucket.com/albums/f92/Woxbox/Crewatwork.jpg

[Nanoose]

Does the pin swivel? The socket for the oarlock is let into railing of Nanoose and supported by a wood block. If I simply need to put in a pin with a grommet this could be fairly easy...of course I'd have to figure out how to tie a shippy looking grommet.

Dave

[Thorne]

Nope, the pin is fixed, but of course the grommet or line will twist enough to let you row.

Any good knot book should show how to make a grommet -- or just splice a small loop of line back onto itself.

http://www.chisholmclan.com/fairwinds/knots/truelove/truelove.html
http://www.chisholmclan.com/fairwinds/knots/truelove/fig1.jpg

[Canoeyawl]

Have them hot dipped galvanized. They will be beautiful and last forever.
If you can find a few friends with boat parts or have other objects to be done at the same time there will be a significant savings. They usually charge for a minimum of 100 lbs. I throw in an old anchor and some iron garden ornaments to get the weight above the minimum. The last time I did this it was about $50/ 100lbs.

[Cuyahoga Chuck]

Hold on ship,mates. There is "wrought iron" and there is "wrought iron".
Real wrought iron is almost pure iron. Unlike steel which has a percentage of carbon that causes voltaic action and, hence, rust, old fashioned wrought iron is so pure that corrosion won't destroy it over hundreds of years. It develops an oxide coating and that's about it.
Those Viking boats that are recovered, every so often, have their lapstrakes nailed with wrought iron nails that are still intact.
I would think that hand forged wrought iron hardware would be a tribute to our long dead nautical predicessors who never saw any kind of boat hardware but hand-made wrought iron.

[Bruce Hooke]

Yes, but to make true wrought iron you have to get the real stuff as your raw material. This can be done but it is very expensive. The only source of true wrought iron I know of is in England: http://www.realwroughtiron.com/

Simply heating and hammering mild steel does not turn it into the historic material know as wrought iron. This is a common confusion.

[Nicholas Scheuer]

the genoa winches. Works fine!

If the Blacksmith's intent is to actually cast oarlocks in green sand, an alternative iron alloy would be what's called Ductile iron, or Nodular Iron. It is much tougher; able to withstand shock loads better.

Years ago, when I worked for a manufacturer of castings for plumbing and drainage systems we would cast the floor or street gratings in Ductile Iron as an extra cost option. I no longer remember the particulars of the alloy, but it shouln't be too difficult to Google it. Otherwise it handles much like Grey ("cast") Iron.

Moby Nick

[Thorne]

My experience with this material is from the historical perspective of body armor and some weapon parts.

Historical sources show armor was made and often just left black from the forge, or sometimes coated with grease for the traditional russet / browning finish. Some of these pieces saw a lot of hard use outdoors in wet weather before making it into a museum.

Try the same thing with replica armor made from mild steel, and it rusts rapidly away unless painted / lacquered / protected. In particular the traditional browing method fails and turns to rust instead of a protective coating.

Even "steel" in the 17th C was a lot closer to ductile iron than it is now, and this explains why some traditional finishing methods just won't work on modern repro armor and weapon hafts/parts.

[seo]

If I needed a single strong oarlock, I'd probably turn the shaft of the lock out of a scrap piece of stainless steel prop shaft, and then weld on a bent lock with a welded stiffening rib. It would not be as beautiful as cast or forged, but it would not rust, and would be very strong. The socket I'd make out a piece of stainless pipe welded to a stainless bolt flange.
seo

[Ian McColgin]

Anyway, wraught iron is finaskind. Forget galvanizing as it's not needed and will wear off anyway. Splat it with anhydrous lanolin or something.

Thole pins are nice as well. If you make the part of the loom that lands against the pin fat enough, you'll not need the grommet as the motion of feathering will keep oar against the pin on the return stroke. Much of the advantage of a thole pin in rough weather is that if you do catch a wave with your oar, getting back to rowing position is easy. That advantage is thrown away with the grommet.

G'luck

[Frank E. Price]

Another possibility, if you would be willing to get rid of the existing socket and pad, is a lifeboat oarlock. There is a store in Anacortes, WA, that sells salvaged fittings off old boats and has them usually. I would think there would be something similar in Victoria, or Vancouver for sure.

The locks I'm thinking of are one piece, permanently mounted, huge, and have no moving parts. They are simply two horns cast into a solid base, all galvanized. If you find such a fitting and it hasn't rusted after several decades in a ship's davits, I should think you wouldn't have to worry about rust thereafter. Just a thought.

Frank

[paladin]

It just so happens that I have a spare pair of Bronze ourlocks in the shed......might fit your project......