Well how hard could it be? An oar is just a piece of wood properly shaped and here am I a budding master builder wise to the ways of epoxy. My previous boats had been propelled with a pair of 5 1/2 foot oars that I had whipped up from some spare 2X2 studs and scrap pine. A set of oars would set me back $60.00 and I had better things to do with my money – especially since a couple of good lengths of wood would be about 1/4 that cost. As well as a couple of hours that I could easily spare. What could be simpler…
Well reality is always ugly and I have had a sobering reminder that not everything can be remedied by slapping on more fibreglass tape and filler. I had done a search of the net under “building oars” and got a couple of very helpful sites. But there were also some warning signals the first of which was that I had to apply a detailed set of mathematical computations and calculations to determined how long the oars should be. The Shaw and Tenney site (now there’s some beautiful oars) http://www.shawandtenney.com/index.php told me the following:
- Inboard length of the loom equals 1/2 the span of the oarlocks + 2″
- Total length of oars = 1/7 of inboard length multiplied by 25
- leverage ratio is 7:18
- distance from the centre of the leather to end of grip equals 7/25 of the total length of the oar.
On the other hand I wanted oars that fit inside the 7’9″ length of the boat and I though 7 1/2 feet felt like a good length. I’ll build em long and cut to length!
Off to the lumber yard and picked up a couple of beautiful 2X6 relatively knot-free spruce planks. Got home and re-read the instructions. Off to the lumber year to get 1X6 pine which is what I should have gotten the first time. Cost twice as much for less wood with a couple inconveniently placed knots.
Instructions call for cut-offs laminated back on to the oar blanks to build up a 2″x2″ shaft…except a 6 inch board is really only 5 1/2 inches. The details show a bunch of tapered cuts so I plot them out and have at it with my trusted sabre saw only to have an oar blank that looks as if it was attacked by angry beavers. That, as well as a knot just at the juncture of the blade with the shaft meant consigning the attempt to the scrap pile. Off to the lumber year to get one more length of 1X6 pine….
Back to the drawing board – I wasn’t going to get a 2″ shaft out of that approach but my handy calculations resulted in the fact that a 5 1/5″ board could be cut in to 3 pieces just shy of 1 7/8″ …. except that I hadn’t allowed for waste from the kerf. I did abandon my shaky attempts on the sabre saw and resorted to a combination of a hand saw and table saw for the cuts and ended up with something that was at least straight, even if a good deal of planing will be necessary to trim up the faces.
I now have 2 would-be oars glued up and clamped and waiting for tonight’s appointment with the hand plane and spokeshave.