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View Full Version : Lead shot to balance hollow oars?



Steve Lansdowne
07-15-2006, 10:13 AM
I'm considering building some 8' oars with hollow shafts out of three strips of doug fir, with the middle strip and part of the outer two strips that form the shaft hollow to save weight. I'd leave the space between the leathers and the grip square as Culler liked. I'd hollow out this square section (whose hollow would not connect to that on the shaft) and bore a hole somewhere into it into which I'd add sufficient lead shot to help each oar balance at the point where it meets the oarlock. (Doing this separately for each oar would help adjust for differences in wood weight between the oars -- thjat is, one might take more weight than the other in the squre section to achieve a good balance.) Had I easier access to spruce I might go this route, but it seems that the fir would hold up to more abuse and, with the hollow/lead shot arrangement leading to a good balance, be easy to use. I realize that hollow shafts might have some strength drawbacks. Any thoughts on this plan?

Tom Robb
07-15-2006, 10:38 AM
I'd not likely notice small differences in oar weight; your results may differ.
IMHO, the ballance might be most useful if you account for the weight of your hands resting on the handles and still have the blade end a bit heavy. lifting on the handles to get the blades into the water would be anoying/tiresome.
Did you consider birds' mouth construction?

Bruce Hooke
07-15-2006, 11:02 AM
I think there's a good chance that the lead shot would not be necessary to get the oars to balance correctly.

It should be noted that a hollow shaft does need to be a little larger than a solid shaft to obtain the same strength, so your hollow shaft oar will need to be just a little bigger than a similar solid oar.

Other than that, it seems like a lot of work to me for not a lot of gain, but I'm not the one who is going to be doing the work, nor will I be using the oars! For competitive rowing they do go for all sorts of high tech oars, but at a certain point it is worth asking if the rest of the boat, and your rowing technique, are good enough to make the difference in oars noticable...

Graham Knight
07-15-2006, 12:59 PM
I bored a hole into the handles of my oars (from the end) and inserted cast lead slugs to balance them, then plugged the end, they should balance with your forearm rested on the oar. If you balance them without the weight of your arm on them, you'll expend energy lifting the handles to force the blades into the water.

garland reese
07-15-2006, 01:12 PM
on the high tech side of things, the oars are balanced such that when placed in the water on square, the blade will float at the proper level in the water (top edge of blade just sub surface, mol). That theoretically allows a fairly neutral load on the arms in the drive portion of the stroke....... you are simply pulling the oars through, not holding them up or down.
anyway..... hope that helps.

Bill Perkins
07-15-2006, 04:51 PM
Culler left the square section of his glued up blank to serve as a counterweight and felt that was sufficient . By hollowing the shafts you're throwing the balance even further toward the handle end ,which makes me think you won't need the lead .

He had an interesting suggestion for producing oars of equal weight . Before glue up , weigh the component pieces of each oar . Then swap pieces back and forth till you get two oar blanks as close as possible in weight . It's one of the advantages of lamination .Cullers' were solid 3 piece .

almeyer
07-15-2006, 06:25 PM
Steve,
My oars are 8' laminated doug fir with a 1/4" thick ash core running down the middle for strength. After I bought the doug fir I noticed that one piece was definately heavier than the other, so I resawed them both and mixed the pieces like Bill suggested so that both oars are about the same weight. Mine are not hollow, nor do they have any lead plugs, but the balance does not seem to be a problem. But then again, this is my first set of oars, so they could be way out of whack and I'm none the wiser.
You're more than welcome to try my oars out just for funs and grins. I won't be able to make the Lake Charles messabout, but wouldn't mind a good excuse to come up to Austin.
Al

RonW
07-16-2006, 10:12 PM
I have a set of 9 ft. balanced oars. They are so much easier to use it isn't funny. You can concentrate and use your energy on the stroke instead of lifting or lowering the oars.
Balanced oars are well worth the effort and time.

Ian McColgin
07-17-2006, 10:23 AM
I once tried lead (roofing lead wraped around just below the handle) on some hopelessly illbalanced 12' oars. The momentum was absolutely appalling and the oars were very hard to row.

Work at trimming down the looms and blade as much as you dare. I've found most cheap stock oars can loose quite a bit of weight there, especially if you go for an oval section normal to the blade, thus keeping more strength where you need it, and be turned into pretty good oars. I keep planing till I get a nice spring if I put one hand on the handle, the other where the oarlocks should be, and press.

G'luck

Graham Knight
07-17-2006, 10:56 AM
I used Douglas-fir for my oars too, couldn't afford Sitka Spruce, the D-f is very strong and the looms can be planed down very slim, as Ian says an oval section gets the weight down but retains the strength where it's needed. The blades can be much thinner than you might think as well, provided you don't use them for fending off!