OARS FOR SEI.
Lets get the jokes out of the way, the one about this being
a “two oars-power cruiser” and the one
about “keeping things on board oar-derly “. Oh, and the one about the Greek
Bireme that docked too close in at speed, “Dis-Oared-‘er”.
With that out of the way,
I want to show how I go about turning a pair of off the shelf machine
made oars into something that I like to use.
As they come they’re robust, but very heavy and unbalanced, tip heavy so
a lot of downward pressure on the handles to lift the blades on the recovery.
So to make them easier to use, more pleasant and just “nice”
I cut the oversize blades down a little, shave the blades thinner with a ridge
down the middle to keel them sufficiently stiff, and slim the shaft from the
“leather” down to the “neck.
Oars should ideally be matched to the boat, this one being a
sailing boat will have a little more resistance than a lighter and more slender
boat, so needs oars that are slightly more stiff than the ones for the pure
rowing boat.
They need to be practical too, which means a thicker blade
and a more robust tip so I can use them to pole the boat in the shallows or
push off a jetty somewhere.
The species of wood used needs to be taken into account, European
Ash (Fraxinus Excelsior) used to be commonly used and is tough, resists damage
and makes a reasonably good utility oar .
But its heavier than I like, and the costs more than I like to shell out
for a pair of oars that I’m not going to use as the boats primary
propulsion. This is a sailing boat after
all.
Spruce, (Picea Sitchencis) by comparison is much lighter and
is strong for its weight but crushes very easily so an oar made from this may
be easily damaged.
All that’s a bit academic though, as the ones that are
available off the shelf here are stated to be “Tasman Pine”. Good old Pinus Radiata, actually not bad stuff for this use if chosen
carefully.
Its mid range in weight for a softwood, fairly strong for
its weight and if kept well coated with varnish reasonably stable.
So that’s what I’m working with today.
For a boat of this anticipated resistance to movement I
prefer a slightly narrow blade, 90mm wide at the tip, 80mm wide at the neck
end, 6mm thick at the edges of the blade, with a prominent ridge down the
middle to stiffen it, the neck will be around 30mm through the vertical axis (
that’s in line with the blade) and full width which in this case is about 40mm
at 90 deg to the blade, a fat oval section there to orientate the thickest part
of the section to the load.
Tools. Making that
hollow section from the ridge down the middle of the blade out to the edges is
what stops a lot of people. I’m
fortunate to have come across a round
mouthed spokeshave and as a tool “enthusiast” ( not what my wife calls me) I
bought it just in case I found a use for it.
Its not rounded front to back, this one is radiused from
side to side so makes a hollow. Ideal.
But there are other ways.
I”ve used the nose end of a belt sander, offered up at an angle and run
along it will carve a hollow, a small angle grinder with 40 grit sandpaper on a
flexible backing piece will do an excellent job with practice, a random orbital
sander would do the job and in fact that’s what I use to do the finishing, and
if you are either very determined or very lucky, you can use a hand plane with
a rounded blade and bottom.
By lucky and determined, I mean that while those are rare
its not that big a deal to make one. To make mine I used a worn out horse hoof
rasp for the blade, lots of grinding required but its good steel, a block of
beech for the body, an offcut of Australian Jarra for the wedge and a piece of
copper rod to retain the wedge.
There is lots of information on making planes out there on
the net, but most of them overcomplicate things, but if that’s the way you want
to do it, you’ll find it.
So having bought my “store bought” oars, which incidentally cost not a great deal more
than enough of the more “suitable” material in plank form, I first made a
couple of simple “holders” to clamp the shaft in order to work on them.
Next was to mark out the blade and the neck with a ruler and
a sharpie marker, that shape being cut
out with a jigsaw and the edges planed smooth and straight.
The next step was to mark the center of the edges with the
marker, and use a standard block plane to shave a bevel down the face of each
side so the outer edge is at the desired thickness.
This is a guide, don’t go much past that. That’s the
thickness you are after.
Next is to taper the shaft from leather to neck. That’s a straight flat, starting very narrow
at the leather and gettting wider and wider as it gets down to the neck.
You may need to remove some material at the neck to get this
taper right, use a standard spokeshave here to make the hollow from the taper
you are planing to the curve where the blade starts to swell out to its full
width.
Don’t round this area off yet, that comes when the blades
are done.
Out comes the tool you have chosen to remove the material
from the blade to make it “hollow” from the center ridge to the edge.
Work out from the marked centerline down the ridge out to
the edge, I work from the tip in toward the neck as with the taper on the edge
the grain is better to shave this way.
The random orbit sander can remove all the little ridges
that the spokeshave or plane makes, so don’t fuss too much, just try for no
lengthwise humps or hollows.
When the blade is hollowed and thinned both sides, then fair it into the neck, remember that
this is the high stress area of the oar, don’t remove too much material
here, where that central spine merges
into the wide part of the neck is the critical part. Don’t thin that down.
Round the flat that you’ve planed onto the shaft into the
body of the shaft aiming for a shape at the neck which is more like an oblong
with the corners well rounded than a true oval or ellipse, sand off smooth and
coat with varnish or paint.
I’ll be painting the outboard end of the blades with white
paint, the regular flashing of the white is visible from surprising
distance.
I’ll be fiberglassing the tips by the way, it reduces the chances of splitting the oar
when pushing the boat off rocks or such.
Just a little strip of 50mm tape folded over the tip and epoxied into
place.
I’ll go into the leathering and the shaping of the handle
when I get around to that stage.
In the meantime, these oars have lost about 15% of their
weight, and that almost all of it from out on the blade end which makes them
much easier to use.
