Oars, the basic propulsion for row boats. Turns out there was a lot more to know than I first realized. I mean what the heck how complex can two pieces of wood be? First I'm not an expert. Second, the experts all have some minor disagreements but mostly it boils down to what feels right. Now you can't go drilling holes all over your boat to mount fixed oarlocks, leastwise I can't bear to do it. With a sliding seat rig with outriggers its been pretty much standardized except for the angle of the oarlocks and the foot rests. The rest slides so its isn't so critical.
First, the basic oar length formula (25 * (((Width-In-Inches/2) + 2)/7)) I got this from the Shaw and Tenny FAQ page (here.) For my dory without outriggers, it's 50 inches center to center for the rear oarlocks, and 51 inches C. to C for the forward seat. That's an 8ft oar, according to this formula, and it feels right rowing. With the additional 6 inches using the outriggers on either side that allows another 1 1/2 ft oars with spoon blades to 9.5ft. With a Macon blade it might be shorter as the force is more concentrated at the tip of the oar. But I don't have access to a spare set of Macon blade oars to test them and at $400 to $600 a pair I'm not willing to buy a set and ship them back across the country to get just the right length.
For the most forward seat, I added a third set of oarlocks, the width is 40 inches C. to C. which means a 6ft 6" oar. I have 7 ft'er's that I got used which I am using for now (I may sell them and get a shorter set but first I'd like to find a set to try out). The net result is that you must row with crossed hands or you smack your knuckles as you row. Turns out rowing here and at the rear seat you can row at a different pace which makes it easier for rowing with kids who can't seemed to keep the rhythm. Anyway with the 8's in the rear and a 7's up front it might be possible to hit but its lots harder. With all three of us rowing the boat, it doesn't really seem to go any faster but its fun and everyone appears to be doing something useful.
Fixed Seat to oarlock measurement. The minimum is 8" from the front of the seat to the center of the oarlock. The optimum has been recommended to me as 10.5 inches to 11 inches. The boat builder put the set in my boat at 13 inches and that feels about right to me. But I have long arms and a short torso.
Which oars? Well I have two sets of 8ft narrow spoon blades from Gig Harbor Boats. I also have a set of 7ft slightly wider spoon blades and a set of 9.5 open water sculls from Barkley Sound . The Gig Harbor narrow set is really nicely made. I've been looking at the catalog for Shaw and Tenny Oars and those are also really pretty. But I don't have direct experience with them. Long or short when sailing they are all in the way. I'm still trying to figure out a good place to stow them when I'm sailing. (When I race thistles we carry a micro length canoe paddle which is adequate to get back to the dock.)
Wide blades or narrow? Well wide looks cool, its the same surface area but they catch the tops of waves easier on the back stroke. So if you are in mostly quiet lakes you can use either. Open ocean you're better off with the narrow blades.
Spoon or Flat? Well here I don't have the flat blades. I was talked into getting spoons by the experts and I must admit it feels better than I remember it ever did with those old camp oars. And the spoon blade oars have that "spring" to them as you flick out the last bit of the stroke. But it does in crease the cost and if its just for the kids to hack around who cares. They'll hit the beach and slash each other with them and abuse them. On the other hand maybe that's why it took so long for me to get back to rowing. All those awful memories of splintery old stick oars. Who wants to do that?
Oar locks? What shape? The boat came with the "O" shaped ones and I really like them. Its a bit harder to quickly pull the oar from the oarlock but then the oarlock is right with the oar. No forgetting them. On an old camp boat I had those "Davis" oarlocks which are the "U" topped ones only the base rotates so that you can have it hang down inside the boat. You can also achieve the same effect using the keeper chains. (Shaw and Tenny). As a kid I remember that it was hard to learn to smooth out my stroke and keep the oar in the oarlock. For that reason alone if its been a while since you were rowing I'd go with the "O" ones. But this is a personal choice and there were so many types of oarlocks because there were so many uses. Bob, who has the Whitehall loves the "D" shaped ones. He uses a square loomed oar and it helps him feather by having a solid "thunk" when the oar is rotated. I don't feather near enough and so the "O" is fine for me rather than do a 1/2 rotation onto the edge of the square. On the other hand Rich Kolin who designs boats is putting those Davis oarlocks in his wooden boats, and rowing with them with a leathered oar was no trouble. (No losing the oarlock!) But if you are thinking about adding outriggers then they would be in the way. It's always something.
Buy or build? Well I don't have the time these days to build near enough stuff. But there are instructions to make the shaft using a birds beak router bit. Use plywood laminates for the oars and wa la! Your own custom oars.
Outriggers? Do I really need those? No, you don't. I'm a boat nut and unless you have my disease you are better off with shorter oars. If you row alone alot on quiet water, and you feel like with the sliding seat you are not getting all the power out of your stroke, just get a set of wide blade oars (Macon or Oxford, or ask how wide the ones are at Shaw and Tenny or Barkly Sound) at the same 8ft length and you'll have nearly the same effect. If you are infected with boat disease and you folks know who you are, and still want longer oars, get the outriggers from WhiteHall Row. I corresponded with a guy who bought the ones from Shaw and Tenny (The discussion is at the Open water rowing list here.) and he was dissatisfied with the quality of the Shaw and Tenny ones. Not enough beef in the design. Apparently there was also a previous version made by Whitehall Row used by Charlie Parks on his Alaska to Seattle Row that it is rumored that they bent and had to be pounded back with a rock because Charlie didn't have a hammer along with him. (Didn't he have an axe, he talks about building campfires?) Anyway the Whitehall row ones are working fine for me. I'll update this page if that changes. The only change I've made to them is that I removed the bolts holding them to the bracket that stays on the boat and put in fastpins. This way I can remove them when I'm primarily sailing or using the 8 ft oars and they are now completely out of the way. Oh yeah I filed them a bit after they came so that they lay flat on the gunnel. Also the outriggers came with an oarlock and I'm going to have to cut it off because when I row with the 8's it makes me have row crossed hands if I use it, and it hits the oar if I use the one in the gunnel. Dang, as its a bunch of nuts to take it off, but I'm not going to risk cutting the hull when I cut the brass. Oh well. Messing about with boats is supposed to be fun!
Lastly again, I'm not an expert on oars, ask questions, measure at least 3 times before drilling, use lots of backup plates to spread the load. And as usual, your actual mileage may vary.