Seat Drops (Bolt Covers) -- Why Use 'Em?

[alsg]

The seats on my tandem cedar strip canoe hang from the gunnels using silicon bronze carriage bolts, nuts and washers. When I built the canoe, I put off making/installing wood drops to conceal the bolts while I paddled the canoe and made sure the seat heights were what I wanted.

I always figured that, after I got the height right, I'd make and install the drops. But I'm now about to start my fourth season paddling it and I still haven't installed wood drops. And other than possibly for cosmetic reasons to hide the silicon bronze bolts (the sight of which don't bother me in the least), I can't see why I would.

Not only is it more weight to install drops (ok, not much), but I continue to tell myself that by foregoing drops it is possible to adjust seat height on a trip for a paddler wishing to raise or lower their seat with just a pair of pliers to adjust the nut). Admittedly, I've never done that. But I could. If I install drops, I couldn't raise the seats unless I shortened the drops; and lowering the seat would require, new longer drops to hide the bolt.

The seats are currently out of the canoe (which is getting re-varnished) and I'm wondering: what am I missing out on by never having installed wood drops? I have noticed that, after car topping, I occasionally have to use my thumb to push the carriage bolt head down 1/4 of an inch or so to fully re-seat it in the gunnel because the jostling from the road has caused it to work itself part way out. But this obviously isn't an issue when the canoe is right side up and I'm sitting on the seat. In any event, I intend to remedy that issue by installing a washer and nut under the gunnel to keep the bolt fully seated while car-topping So what sweet mystery of life am I missing out on by forsaking wood drops?

 

[Mrindy]

My best guess is that it protects you from accidentally scraping a thigh on metal thread and possibly prevents the bolt from bending to an extreme angle and weakening. My only evidence for this is from my reckless cousin who thought to ratchet strap one of my canoes to his car roof with the strap tension loaded on a seat. Thin Pvc covers were not enough to support that bolt from bending in half. I suppose gravity could wrench it the other way with a heavy paddler leaning and bending them too? Really good question - curious if any more-experienced trippers have insight into their true intended purpose.

 

[Jatfomike]

I would put the drops in.....Whether you realize it or not, your butt wiggling around on the seat puts a lot of stress on the bolts which could cause them to bend or break(I've seen it before)....that same stress could cause issues with your gunnels.....the bolts wiggling in the holes could widen them out and create more slop....

Mike

 

[Iskweo]

Good question. I am not sure that you need them really other than for cosmetic purposes. There is a small bit of utility to be had from simple round drops. Stiffens it all up and is a bit more solid I suppose. I like to use a block to add more rigidity, but I think a cleat epoxied or screwed to the sides of the hull would be far better than drops in any event.

Best answer....keep paddling

 

[yellowcanoe]

Simple round drops don't really do anything.. Bridge drops do add stability and eliminate wiggle.. Having had a seat tear out because of a round drop on the French RIver led me to only go to span drops.
https://www.edscanoe.com/seathanger.html

Eds does sell simple drops too.

 

[Cruiser]

Once you snug up the bolt to a wooden drop, it actual locks the seat to the gunnel, stiffening the the "hang" not allowing the seat to sway as much, as well as providing some lateral stiffening gunnel to gunnel. So instead of the seat just being a hanging dead weight, it will contribute to the canoe rigidity in that area.

Brian

 

[alsg]

Those bridge drops might provide stability but they must be designed for a canoe with nice flat, level gunnels! They’d be a bear to install in mine! They would need to be scribed at the top lengthwise to follow the curves of the gunnels as they rise to follow the shear line up the bow/stern. And because the gunnels tip inward following the tumblehome of the hull, the edge of the bridge would need a rolling bevel to seat flush to the bottom of the gunnel. I also don’t drop my seats nearly that far!

 

[yellowcanoe]

Those bridge drops might provide stability but they must be designed for a canoe with nice flat, level gunnels! They’d be a bear to install in mine! They would need to be scribed at the top lengthwise to follow the curves of the gunnels as they rise to follow the shear line up the bow/stern. And because the gunnels tip inward following the tumblehome of the hull, the edge of the bridge would need a rolling bevel to seat flush to the bottom of the gunnel. I also don’t drop my seats nearly that far!

We make our own.. They are not fixed in depth.. I paddle with a nine inch clearance in front and ten in the back so the bridge is about two inches deep... It is not a big deal.. And there is no tumblehome in the bow of my boats.. Most of them are solos and tumblehome is present and has no effect.. Colden,Bell, Wenonah,Loon Works, Hemlock, Swift ..we have at least one of all of them..

It's not hard to adapt.. Some basic shaping with wood working tools..even a microplane.

 

[Guest]

What Jatofmike, YC and Cruise said.

Without drops of any kind the naked bolts or machine screws do not provide much rigidity, either side to side or fore and aft. Even slight movement of the seat will eventually wear at the holes in wood gunwales and in the seat frame itself.

The sway movement also puts a lot of stress on the bolts or machine screws. On many (most) old canoes I have rebuilt that had flimsy drilled dowel drops the 3/16” hardware was bent, and kind of a pain to get out as it wobblewobbled when unscrewed. None of that wanked hardware was worth saving for future reuse, into the trash it went.

Like YC’s experience I have seen bent and wanked seat hardware fail catastrophically. Often at the most inopportune moment, say a desperate brace in WW or in the middle of some misread line. The result is usually a swim.

Full truss drops (bridge drops) add considerable stiffness. Envision the seat sans any drops as a swing. With a full truss drop any sway forward or aft is eliminated. Those truss drops add lateral stiffness as well, almost like another thwart.

Those bridge drops might provide stability but they must be designed for a canoe with nice flat, level gunnels! They’d be a bear to install in mine! They would need to be scribed at the top lengthwise to follow the curves of the gunnels as they rise to follow the shear line up the bow/stern. And because the gunnels tip inward following the tumblehome of the hull, the edge of the bridge would need a rolling bevel to seat flush to the bottom of the gunnel. I also don’t drop my seats nearly that far!

Full truss drops are kinda tricky to get right even on a more accommodating inwale. Shorter drops are easier though.

A compromise between near-useless peg drops and a full on truss drops is to use something wedge shaped \_/. That shape provides a lot more beef at the top where the seat drop rests below the inwale, and it is easier to shape the for the sheerline rise, and any inward tilt of the gunwale angle. Done individually, on four wedge drops, those are easier to solve than the mystery of a custom in several angles and dimension full truss drop.

On one of the build threads Jim Dodd has photographs of some elegant, custom shaped drops.

Even rectangle drops or the cut off ends of a seat frame are better than nothing, but with a simple dimensional piece of hardwood as wide as want the seat drop depths you can cut four seat drops
\ / \ / \ drill them and shape the angles.

 

[Jim Dodd]

Confession !
My first stripper, I just put a length of Poly tubing over the threads, of the 1/4" ZINC carriage bolts. Worked good, just ugly !

In my defense, I was in a hurry to paddle that canoe, after all It took me 9 months to build !

Jim

 

[memaquay]

I just use round dowel stock from the hardware store. Once I tighten up the bolts, the seat is solid. There is no play, side to side or back and forth. When I first started building strippers, I used 3/16 brass type bolts that looked really nice and cost as much as a prosthetic leg. I had two failures with them. For the last fifteen or so, I have used 1/4 inch round headed carriage bolts from the hardware store, 25 cents each, with lock nuts. No failures ever, and like i say, once snugged up with the dowel, solid as the Canadian Shield. And it matches my helmsman varnish job!

 

[alsg]

Yup, I also use 1/4" round head carriage bolts. I spent for silicon bronze because I knew the canoe would sometimes be in salt water or brackish water.

 

[alsg]

Confession !
My first stripper, I just put a length of Poly tubing over the threads, of the 1/4" ZINC carriage bolts. Worked good, just ugly !

In my defense, I was in a hurry to paddle that canoe, after all It took me 9 months to build !

Jim

How is it holding up?

 

[Jim Dodd]

How is it holding up?

If I ever dig it back out ? I could tell you ! Ha !

This was my first build, back in 1990-91

But seriously, the red rust that developed between the the bolt, and plastic tubing, is visible, and not appealing.

Structurally it held up, and served the purpose. There is really little stress on hanger brackets .

Jim

 

[Jim Dodd]

Here is what I've used on everything, since my first build !

The drops are just cut off's from my seat frames, matched to the contour of the hull.

The seat doesn't move side to side, and very little fore and aft, because they are less than 3".

 

[yellowcanoe]

Jim do you ever catch your foot or leg on the exposed bolts during capsize? We cut ours off and capped them for that reason Yes you do lose the ability to lower the seat.
The newfangled thing is now seat supports by carbon pods. I dunno about this.. Nothing can be moved.
https://www.swiftcanoe.com/carbon-components

 

[alsg]

Here is what I've used on everything, since my first build !

The drops are just cut off's from my seat frames, matched to the contour of the hull.

The seat doesn't move side to side, and very little fore and aft, because they are less than 3".

I also hang my seats less than 3 inches. Maybe that's why I can't understand some of the comments about all the seat movement. I've never experienced it, even without drops.

 

[Cruiser]

YC ... I wait till I try the boat with the drops, when I am happy, I then cut and cap as well. If I want to change it later, seat drops are pretty easy to redo and new bolts aren't that expensive.

alsg ... a lot of what you end up doing with the seat drops depends on the boat you are using, if it's a larger shallow arch tandem, there is so much stability higher seats are no big deal, in a narrow round bottom solo, lower seats may be required to help with stability ..... I don't think this is a one size fits all discussion. I will say though, using simple bolts, to free hang a seat at 3" should have some sway, but as that distance lessens the sway lessens as well .... are you also using something else to stiffen the bolt (like a second bolt to hold it steady?

The seat drops can be simple drops (length of wood, metal /plastic/composite tubing) or bigger bridge drops, again, the simple drops are lighter and fit in a lot of boats, but some situations will beg for the bridge versions.

 

[Jim Dodd]

Jim do you ever catch your foot or leg on the exposed bolts during capsize? We cut ours off and capped them for that reason Yes you do lose the ability to lower the seat.
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Yes, I trim them, only after I've paddled the hull, to verify I like the height !

I just trim them very close, and round off any thing sharp ! I also use Nylocks (stainless)

Jim