I have a 16’ Wenonah Aurorah. I want to be able to paddle solo without needing to bring weight to trim the bow, so I’d like to add a third seat. The gunwales are riveted on, and the existing seats have metal brackets that fit under the gunwales — is it possible to add the seat?
If so, how do I determine the best location?
First, to position a center seat so that the canoe is trimmed neutrally requires placing the seat aft of the geometric longitudinal center so that the paddler’s center of gravity is at the center of buoyancy.
In a canoe with a very asymmetrical water footprint the longitudinal center of buoyancy may be very different than the geometric longitudinal center but the Aurora appears to have a relatively symmetrical water footprint, at least close enough to not worry about the difference.
The paddler’s center of gravity will vary depending on your paddling posture and body dimensions. For a seated paddler with long femurs the center of gravity will be somewhat farther forward than for one with shorter legs, for example. For a kneeling paddler the center of gravity tends to be around the front of the paddler’s navel or up to an inch forward of it, but kneeling paddlers position their rear ends differently on a seat. Some just lean their butt against the front seat frame rail, others sit back on the seat.
As a very general rule figure your center of gravity is going to be between a half inch and an inch and a half forward of the front edge of the front seat rail and position your seat accordingly. That will place the center of the seat frame well aft of the longitudinal center of the canoe.
As for hanging the seat there are a couple of options but you will need a pop riveter and appropriate sized rivets and an electric drill with bits. Ed’s canoe makes a four piece set of aluminum seat hangers: Aluminum Seat Hanger Kit
These are lighter than hangers that utilize one large piece on each side but the one-piece hangers are more rigid. Rutabaga sells the one-piece type of seat hanger: Wenonah Canoe - Seat Hanging Bracket - Silver (Pair)
The way these work is that the top of the hangers go up between the inner side of the hull and the inwale. To do this you will need to drill the heads off of several pop rivets holding the gunwales on at each side to get clearance for the hangers. Then after sliding the hanger up in place you drill holes through it at the appropriate locations and pop rivet it in place as well as replacing any additional rivets you had to drill out.
The hangers may be too long and might position the seat lower than you would like. You can shorten them with a hacksaw. Also, since your seat will be positioned well behind the geometric center of the canoe where the sheer line is rising toward the aft, if you want a level seat you will need to cut the tops of the hangers off at an angle.
I’m just a beginner but I just got done doing some seat moving on my tandem canoe to use it as a solo.
When you sit backwards in the bow seat how much weight do you need to add to the new bow? That might be a clue to how far you would need to advance it. I read where many people just do that, sitting backwards and are fine and kneeling from that location often they say works good.
I moved the bow seat about 8” to the center and that was my best guess. I will be finding out soon as the water is getting warm enough to get out. I don’t plan on doing much kneeling but I do have a pad if I want to.
Another thing to keep in mind as you get closer to the center the width gets wider and might cause some paddling issues. I’m going with fairly long double ended paddles.
As to hanging the new seat whatever direction you will be going if you don’t want to drill rivets out I would think you could drill and hang the seat off the gunwales like other canoe makers do. I could be wrong, but from your picture your gunwale looks similar to how OT does it.
Depends on the specific model. If it is a Royalex or T-formex hull it will have squared off synthetic gunwales with a thick enough inwale to drill through to suspend seats.
Wenonah’s composite models often come stock with lightweight extruded aluminum gunwales. These have a rounded upper contour and an inwale that is too thin to suspend a seat from.
Thanks for the insight. It looks from the first photo he posted that they are the synthetic version (black plastic of some sort). Would that be the type safe to hang a seat on? 
Yeah, if that is indeed a picture of the OP’s boat then drilling through the inwales and using long machine screws to suspend a center seat would work. Some type of seat hangers would still be needed and some pretty long #10x24 stainless machine screws with matching stainless nuts with nylon locking inserts.
It is also best to use a stainless finish washer of the appropriate size to distribute the stress on top of the gunwale to prevent the machine screw heads from “sinking in”. Seats, unlike thwarts and yokes, tend to bear a lot of weight on them for prolonged periods of time. I have seen many synthetic gunwales bearing the weight of seated paddlers deform.
Something like this seems like it would work.
I would just make my own made from sheet aluminum, but for someone without equipment to make bends this seems like an option. I’m sure others make “C” brackets.
Thanks for the advice, all. Especially your post on water footprint, pblanc, I learned a lot from that.
That is indeed a photo of my boat — it’s Royalex with the black synthetic gunwales. Glad to hear that I can suspend a seat from the inwales, I like that option better than adding hangers underneath the gunwales. This way I can remove the center seat if I want the space.
I would check out Ed’s canoe. Ed sells center seats with wide seating surfaces as well as sets of one piece truss seat hangers and the necessary hardware with 6" stainless steel flat head bolts with nuts and finish washers.
