Decision Time—Thwart Interfering with Seat Back

[Black_Fly]

Just paddling the Phoenix for the first time. First paddle with new shoulder.

The only problem is the rear thwart, which is too close to the seat to recline to a comfortable position. I have 3 choices:

1. Move the thwart back a couple inces to accommodate the back saver

2. Move the seat back 3” and eliminate the thwart or move it back 5”.

3. Do nothing and suffer with my Crazy Creek type backrest instead of the back saver.

There are advantages and disadvantages with each course. Any thoughts?

 

[kahel]

What do you feel most comfortable with?



Your answer to the question is then the solution.

 

[Black_Fly]

What do you feel most comfortable with?



Your answer to the question is then the solution.

In the NC I prefer the Backsaver. Need more support. So if I want to use it in both boats, I need to move the thwart back. Im not sure about repositioning the seat, doing without that thwart altogether.

 

[Black_Fly]

Would moving the thwart a couple inches diminish the hull strength much?

 

[M Clemens]

Do you really need to move it back that far? The curved thwarts Northstar uses on the pack canoes can buy maybe another inch. Otherwise, as much as I hate drilling more holes in the gunnels, I'd move the thwart.

 

[Odyssey]

Listen to your body. Chances are if you're anywhere near grey beard country then you've earned some comfort. Besides, isn't it more important to have the seat ideally located for trim purposes than the thwart? The thwart moved aft a couple inches might make a world of difference to your position comfort (using the back support), and little difference to the canoe. Eliminating the thwart or moving the seat sounds extreme.
Engineers will correct me as necessary. I'm cool with that. Good luck tweaking the new ride.

 

[stevet]

Can’t imagine moving the thwart a couple inches would be detrimental to hull integrity. I have moved thwarts many times without problems. You could always call Northstar for verification.

 

[Sliding Focus]

I agree with the folks who suggest moving the thwart. Replacing it with a curved thwart also sounds like a good, creative solution. Either sounds both easier and better than moving the seat because a) it means drilling fewer holes and b) it keeps the seat closer to the middle of the canoe. And it seems worth doing the work to increase your comfort!

 

[Gamma1214]

I tend to operate on the premise that most things are over-engineered so modifications to structural supports &/or safety items are totally ok.

If you're really worried about, take the thwart out completely, carry it around the yard and maybe take it for a paddle. If it flexes like a wet noodle, put it back but if (as I suspect) it makes little difference, move it back far enough that you're comfortable with your preferred back support, reinstall it there & paddle on.

 

[MrPoling]

I've heard having rearward trim encourages the stern to sink more as you approach hull speed. It feels true to me, especially in short light canoes and kayaks. So I'd be inclined to give the factory seat position a few paddles before changing it.

I wouldn't worry a bit about moving a thwart a few inches, but I like the idea of replacing it with a curved one even better.

 

[Glenn MacGrady]

take the thwart out completely, carry it around the yard and maybe take it for a paddle. If it flexes like a wet noodle, put it back but if (as I suspect) it makes little difference, move it back far enough that you're comfortable with your preferred back support, reinstall it there & paddle on.

This makes sense to me. See how the canoe performs without the thwart. The seat itself should provide structural stability at that point. If the removed thwart nevertheless makes the gunwales too floppy, move the thwart back or try a curved thwart. I wouldn't move the seat if it's positioned properly for trim.

 

[M Clemens]

I also notice that you have the full sitting drops installed on your seat. By shortening the drops and raising the seat some, you will alter the pivot point of the Backsaver and allow for more recline. Most of the Northstar hulls are stable enough you probably won't notice the difference.

I think removing the thwart completely might negate the warranty on a brand-new hull, unless you get their blessing.

Lastly, a little padding on the Backsaver works wonders.

 

[M Clemens]

View attachment 140316

 

[scoutergriz]

to me that thwart looks too far forward- the seat already provides some stability to the hull anyway especially if the risers are screwed or glued to the sides of the seat. I'd move the thwart- just remember that cutting the thwart means you won't be able to put in back in the same location, and moving it without cutting can make you "taco" the hull- too wide means spreading the hull which can hog the bottom, too narrow pulls the hull in which can increase the rocker.

 

[M Clemens]

to me that thwart looks too far forward-

That's kind of a common design feature on most of the Northstar solos. When I was able to test paddle their entire line (solos) at the WPSCA before the pandemic, I spoke with their team about the rear thwart digging into the small of my back with the sitting drops installed, especially on the Trillium. After a lengthy explanation of their design components such as partials, rib and thwart placement, it was actually they that suggested installing the curved thwart on my Trillium if I were to leave the sitting drops in.

 

[Gamma1214]

I will admit that I like the curved thwart... seems like the easiest solution if it gives you the clearance you need. Only $30 on their website... I've spent more on pizza.

 

[Pseudonym]

Trying a curved thwart as the first step makes all the sense in the world.

I wouldn't remove the thwart entirely and rely on the seat alone. The seat assembly provides far less lateral rigidity than a thwart, because the seat drops are perpendicular to that hull-spreading force that the thwart resists. Putting them in tension could easily destroy/degrade the connection between the drops and seat and/or gunwale. Without a thwart, you'd be relying on the integrity of the the ninety degree connection between the drops and seat to resist the lateral spreading force, so you'd need serious gussets at those connections before they could hold up. That's feasible, but you'd need to redesign the seat drop assembly and it's likely you would need to concede seat width and thereby bum-comfort (that's a technical term). So when you scooch your bum next to your paddle-side gunwale, you'd likely push up against those gussets. It's feasible though and it'd be interesting to see it done in wood.

If the curved thwart doesn't create enough space for your back-saver, then moving the thwart back a couple inches is no big deal, once you're willing to concede the vestigial holes from the original location. It'll have a negligible impact on hull flex. Fill them and forget them, because you're comfort is far more important. I imagine Northstar keeps the thwart as close to the seat as they do, not because its a structurally critical point, but because by keeping it close to the seat they maximize open space in the rest of the canoe for gear.

If you wanted to be sure about how moving the thwart back might feel before you drill the gunwales, then you could test it by clamping the thwart temporarily to each of the gunnels, and also place a third larger clamp athwartships, spanning from the outer edge of each gunwale all the way to the other side. That would work for a gingerly test paddle. Forgive the crude drawing but this is what I mean:

 

[Black_Fly]

NS says 2” no problem. Wonder why they put it so close to the seat to begin with.

 

[Alan Gage]

NS says 2” no problem. Wonder why they put it so close to the seat to begin with.

Because then people would complain about not having enough room for their packs and barrels behind the seat.

Alan

 

[ppine]

Moving a thwart is easy.