Seat/thwart placement guidance

[patrick corry]

I may need guidance. I have reached the point in my Chestnut Bobs Special restoration where I'm anticipating putting the canvas on. Prior to doing so, in order to maintain structural integrity, I will need to install the center thwart and seats. I can use the old inwales to duplicate the original locations, but the seats were placed in pretty extreme positions. The front edge of the stern seat was located on the rib on which the stern stem terminates, resulting in a tiny seat quite far back in the canoe. The bow seat was originally in a 'normal' location but at some point a previous owner cut it down and moved it forward to a similarly extreme location- with very little leg room! I have no problem with the rear seat location for paddling function since I will use this as a solo canoe and paddle from the bow seat "backwards". However, I also want the stern seat frame to act in place of a quarter thwart since this canoe, like most of the 15' Chestnuts, only has a center thwart, so moving it a bit ahead will help with that.

The bow seat original location, noted from the original inwales, had the rear edge of the frame 29.5" from the established location of the center thwart. Measuring three other 15' canoes, yielded similar measurements for the rear of the bow seat at 23", 25.5" (Chestnut Chum), and 27.5" from the centerline. In my experience closer to the center is better for solo paddling.

Lastly, in order to create the best balance for portaging, would it be best to install the seats in the desired locations, then determine the balance point precisely in order to install the center thwart rather than arbitrarily choosing the measured center? I do prefer to have the canoe slightly weighted back heavy rather than having to "lift" the front to see where I'm going. I typically use thwart pads rather than lashing paddles to support the canoe on my shoulders. I'm sure the paddles add weight forward and affect balance.

 

[Worth Gretter]

Patrick, I have been facing the same question on the canoe I am restoring. It is an 18 footer, apparently a Maine guide canoe from the early 1900s by an undetermined builder. It appears it was built without seats as there is no trace of attachment points.

I have three modern canoes, 13, 16, and 17 feet, so I measured the seat location in them. It turns out that, in all three, the center of the bow seat is 30% of the canoe length from the bow, and the center of the stern seat is 20% of the canoe length from the stern.

I am going to use this as guidance for the seat placement in my project canoe.

Doing the math on your other three 15 footers, I get the front seat at 34%, 33%, and 32% of the length for the placements you describe. I am assuming the seat is 10" front to back (so the center of the seat is 5" from the back edge), the hull is 180", and the center thwart is at 90".

 

[Glenn MacGrady]

As you know, Patrick, I don't restore wood/canvas canoes. But I have placed and re-positioned seats, saddles, pedestals and thwarts in many of my canoes. I position them in the places where it is most comfortable for me to control the canoe, based on the sizes and weights of the actual paddlers who are likely to use the canoe and also based on whether the canoe is going to be used as a tandem or solo.

To me, factory production canoes from Chestnut, Old Town or whomever were placed in formulaic average places, for average tandem paddlers, of average sizes and weights, of the time in which they were built. If you are motivated to match this factory production placement of the seats and thwarts in a short tandem canoe like a Chestnut Bobs, for historical accuracy reasons, then ignore what I am writing in this message about my philosophy.

I want to actively paddle my canoes. Therefore, I want to be be comfortable in them, have them trim properly if a solo, and be able to employ solo propulsion and control strokes in all four paddling quadrants of the canoe. Standard factory tandem seating positions are highly likely to be sub-optimal for my purposes; hence, I customize seat and thwart placement. If I were going to solo a Bobs, and I have one in Aramid, I would put in one centralized solo seat and put structural quarter thwarts in the bow and stern.

In that case, I wouldn't have a centralized portage thwart because it would interfere with my solo seat. As a soloist, a centralized solo seat is far more important to me than a centralized portage thwart because I paddle my canoe 99.99% of the time and carry it only 0.01% of the time. I'd use a removable portage thwart instead, as I have in my Thurlow wood/canvas repro Morris, which you've seen . . .

. . . or use a clamp-on thwart.

If, however, you are determined to put your solo seat further back from center than trim-optimal, so you can also have a central portage thwart, then it makes sense to determine your portage thwart balance point after all the seats and thwarts are installed where you want them. This means that your centralized portage thwart will likely be somewhat fore or aft of geometric center.

 

[MGC]

I recall a break on a particular portage. My wife, bogged down with two dry bags (one front born, one back born) and a pair of paddles was asking me why we had never done this particular route before. I remember responding, "too many carries." She asked in return, "then why are we doing it now?" I responded, "because we've never done it before." At the time it made perfectly good sense, and it was 100% true. By the time we were done with that trip we had carried over 11 miles and we paddled 22.
For me, the position of the center thwart is one of the most important details for a canoe that I plan to regularly use. Granted, I only have one small Cnut that is primarily used for solo paddling. Even so, that canoe is also set up so that I can toss it up on my shoulders at a carry. I have never seen a need to center a seat in it.
I am constantly annoyed with my Rushton's whenever I need to move them around or cartop them. The absence of a center thwart obligates me to find someone to help me carry them.

 

[samb]

I am constantly annoyed with my Rushton's whenever I need to move them around or cartop them. The absence of a center thwart obligates me to find someone to help me carry them.

For my Rushton I have made a removable thwart.

The ‘v’ shape at the far end locates on a #10 screw which is under the gunnel. At the near end a slider which can grip the other gunnel. Both ends have leather to protect the gunnel.

The only problem I have with it is the height of the finger nut that tightens the slider, which catches on the roof rails as it is taller than the roof bars - one day I’ll get a slimmer one.

 

[patrick corry]

For me, the position of the center thwart is one of the most important details for a canoe that I plan to regularly use

Glenn and I probably had a similar discussion regarding seat placement in my Island Falls Willow restoration over at canoetripping.net at some point in the past. That canoe, unlike this one, is a dedicated solo. Glenn's comment regarding the percentage of portaging vs. paddling is a valid one, and I should have made it clear that this canoe will be used for plenty of portaging. For that reason I do not want to have to carry or affix a dedicated yoke for each portage. Sometimes, in the area in which I paddle, it is necessary to paddle mere yards before needing to pick up and carry again to the next pond.

Also, the optimum seat position for paddling while solo and empty for day paddling is quite different for paddling loaded for tripping. In my paddling I find that my (minimalist) tripping load stows well ahead of me just behind the stern seat- remember, I'm paddling a tandem canoe reversed, from the bow seat- and trims the boat nicely. For day paddling I carry a bladder of water with about 35 pounds of water which when stowed under the stern seat accomplishes the same trim.

Lastly, in this canoe which may be quite old and traditional, I wish to retain the appropriate 'look' of the original tandem seating. With that said, I'm perfectly willing to alter each seat location a few inches here or there to aid the paddling position without spoiling the traditional look. Having clamped the seat frames in their likely final location I then balanced the canoe to find the correct location of its center of balance. Then, I clamped the center thwart at that location with a few adjustments to achieve neutral ,or slightly rear heavy, balance once on my shoulders with the pads I use.

 

[Worth Gretter]

So, you clamped the seats in place and then found the best location of the center thwart for balance. I'm guessing your chosen location is very close to the actual center, because you want it "rear heavy" and the rear seat (although a bit smaller) is further away and has more leverage. Have I guessed right? How far from the actual center is your preferred location?
-Worth

 

[patrick corry]

You are correct Worth. The measured center and the "balanced center" of the thwart with seats in position ( and equally weighted clamps so they don't skew the result), differ by about 1". That is, the center of the thwart in the desired position is 1" behind the balance center.

 

[Worth Gretter]

Great, it sounds like it worked out the way you wanted!

 

[patrick corry]

Yes, I think so. Just took a bit of fiddling around, standing back and looking at the result, and test balance for carrying. Sometimes thinking out loud (or, in this case, in print) helps me to come to a decision.

 

[Glenn MacGrady]

this canoe which may be quite old and traditional, I wish to retain the appropriate 'look' of the original tandem seating.

I figured that, Patrick. Thus my advice to traditional preservationists to "ignore what I am writing in this message about my philosophy."

Nevertheless, as a further ignorable tangent, I will continue on with my—and many other canoeist's—philosophy and experience for future readers who may not care so much about so-called traditional tandem seat positions. First, I don't consider a Bob Special, or any 15' canoe, to be a reasonable tandem canoe for anyone other than small, lightweight people with very little gear. Similarly, the stern seat in my 15' Morris (above) is virtually useless; I keep it in the canoe solely because it looks nice to me. A Bob is more suited as a solo, and 15' happens to be my favorite solo length.

Second, for a solo canoe, only centralized seating/kneeling allows for proper design trim and, more importantly, for the most effective use of all on-side and off-side bow and stern propulsion and turning strokes, as well as for centralized windage. No canoe racer, whitewater paddler, poler, kayaker, outrigger canoe paddler, or freestyle flat water canoe paddler would disagree. Neither would Omer Stringer, Reg Blomfield, Bill Mason or Tom MacKenzie, all of whom solo paddled wooden canoes from a centralized position.

Third, I have ten solo canoes, two soloized tandem canoes and three kayaks. All have original or customized centralized seating, all can be trimmed perfectly whether paddled empty or full of gear, and all the canoes can be portaged with clamp-on or clamp-under portage yokes that can be affixed within a minute. And I would never car top a canoe with a clamp-on portage thwart affixed; it comes off before or after the canoe goes on top.

Fourth, artificial water ballasting a tandem canoe paddled from the bow seat backwards is, to me, a PITA and, even though it can trim a canoe, the aftward seating position still doesn't allow one to use the full complement of bow propulsion and turning strokes, or to provide for centralized body windage.

Different strokes for different blokes.

 

[patrick corry]

I know it's not a big deal, but one more step along the way to getting this old canoe in the canvas. Finished the lion's share of caning on two new seat frames. Only the couching left to do around the border of the frames, then they can go in the canoe permanently and after final balancing for portaging, locate and install the center thwart! Progress. The bow seat on the left has just been caned... hence the darker tone to the cane since it's still wet. It will dry soon and look like the one-day-finished stern seat on right.

 

[Worth Gretter]

Looking really good!

 

[lowangle al]

I'm no expert Patrick, but I'll pass along what Jerry Stelmok told me about center thwart placement that led me to believe that it is pretty standard. He said that on Old Towns the center of the boat falls between the two center ribs and on most other boats it falls on the center rib, and that is where to put the yoke. I'm not sure there is a "perfect" balance point, for me it keeps changing as I change how much I tilt the boat and where exactly it sits on my shoulders to aleve discomfort. A test would be good though as you certainly wouldn't want it to come out bow heavy for some reason.

 

[patrick corry]

I'm not sure there is a "perfect" balance point,

Going deeply into the weeds on this question, I'm finding 'my balance' point using the carry shoulder pads I made which extend ahead of the thwart (away from the paddler position when sitting backwards on the bow seat). The pads sort of cantilever forward of the thwart in order to avoid having the thwart constantly in contact with the topmost vertebrae , I think called the atlas. Some carry yokes incorporate a small cutout to achieve the same result. As a result of the sort of pad forward position, the thwart is necessarily installed about 1" behind the actual balance point. But yeah... balance is an arbitrary thing, since portage trails are rarely all level, dry, and free of obstacles ....

 

[lowangle al]

The important thing is that it works for you, but how will it carry without the pads, or will they be installed to stay on the boat permanently?

 

[patrick corry]

Not permanent, as I switch them from canoe to canoe as the mood strikes me for a particular outing. Even if I don't use the pads, I can lash paddles and carry traditionally. Balance point should remain relatively the same.

 

[Luca Fournier]

the carry shoulder pads I made

Hey Patrick. Any chance you've got a photo of your carry shoulder pads? Super interested. I usually portage with a molded yoke and strap on one of those foam pads. The bob I'm restoring right now has a center thwart I'd like to use so was thinking of making shoulder pads for it. Thanks. Nice caning by the way! I made my seats and will be caning them when I can no longer work outside.

 

[patrick corry]

You'll see them in this trip report: https://www.canoetripping.net/threa...liam-c-whitney-wilderness.127931/#post-142601

I made them up from materials on hand; plywood, foam pads, velour fabric, and standard bolts & wing nuts. Inelegant, but quite functional.