Seat Mounting

Welcome to the new Bear Mountain Builders Forum - an interactive internet service we provide to encourage communication between canoe and kayak builders
Post Reply
The Gutt Clan
Posts: 35
Joined: Thu Oct 21, 2004 4:32 pm
Location: Rochester, NY

Seat Mounting

Post by The Gutt Clan » Fri Feb 18, 2005 4:02 pm

I've seen a variety of seat mount in the pictures on this forum. I've noticed that most people hang them from their gunwales which seems like the hard way to mount a seat. Wouldn't it be easier and perhaps stronger to install a couple of riser blocks on the bottom of the canoe and mount the seat on those? Also, if the canoe was going to be switched from a tandem canoe to a solo canoe, the 'extra' seat(s) could easily be removed to save weight and/or space.

So, are hanging seats very sturdy or are they as fragile as they look? Are there any disadvantages to mounting seats on blocks from the bottom of the canoe?

User avatar
Doug
Posts: 476
Joined: Mon Nov 15, 2004 7:59 am
Location: London, Ontario, Canada

Post by Doug » Fri Feb 18, 2005 4:25 pm

I believe that hanging the seats from the gunwales distributes the weight (of you) over the length of the gunwales / canoe.

I would think that using riser blocks the weight would be in one general spot, under you.
Which may not be a good idea when you slip.
But I will never say, never.

Would your question be in "how" you attach it to the gunwale?
(are hanging seats very sturdy or are they as fragile as they look?)

I have not had a seat fail yet with gunwale hung seats.

Switching from solo to tandem will always be tricky, if you have a dedicated canoe.



Doug
"Some people hear the song in the quiet mist of a cold morning..... But for other people the song is loudest in the evening when they are sitting in front of a tent, basking in the camp fire's warmth. This is when I hear it loudest ...." BM

Rick
Posts: 727
Joined: Thu May 27, 2004 9:23 am
Location: Bancroft, Ontario

Post by Rick » Fri Feb 18, 2005 8:49 pm

The problem with installing blocks on the bottom is that the hull will not flex evenly when going over a log or rock - the edge of the block becomes a high-stress area on the hull which will tend to crack more quickly. Installing the blocks on the sides should be easier on the hull if you don't want to suspend from the inwales.

Bolts suspended from the inwales should be OK with ordinary use, as long as the heads are located closer to the hull's edge rather than further. If they are a worry, a rectangular plate of some kind of material will be more rigid structurally, and won't stress bolts or inwales as much.


I'd still go with suspended bolts, however, seats can be removed easily to convert from tandem to solo, but you might find something else as well.. The bolts will carry a lot of weight, if properly installed - I tested one on a short piece of inwale glued to a piece of plywood and that one bolt and inwale took my entire weight.

User avatar
Juneaudave
Posts: 522
Joined: Sat May 08, 2004 12:42 pm
Location: Juneau, Alaska
Contact:

Post by Juneaudave » Fri Feb 18, 2005 9:28 pm

Hung seats are pretty durable, they just look fragile.....most people bust out the cane before they bust the frame. If you feel you want a riser, maybe you would be better off still hanging the seats, but also put a riser in the middle that rests on a continuous keelson glued along the inside centerline of the hull. That way, at least, you will distribute the weight along the hull and not on a localized area....Juneaudave

sedges
Posts: 290
Joined: Fri Jul 09, 2004 5:37 pm
Location: georgia

hanging tough

Post by sedges » Fri Feb 18, 2005 9:41 pm

I have been hanging seats from my gunnels for decades, never had one fail. My main partner on the water weighs in at 280 lbs and the hanging method works fine. I use 3/16 silicon bronze carriage bolts and a piece of thin walled copper tube for the spacers. I highly recommend an adjustable bow seat. I'll never build another tandem without one. Makes getting a good trim real easy. A properly trimmed and balanced boat works more efficiently and is more seaworthy as well.

User avatar
Bryan Hansel
Posts: 678
Joined: Fri May 14, 2004 6:36 pm
Location: Grand Marais, MN
Contact:

Post by Bryan Hansel » Sat Feb 19, 2005 9:33 pm

Making a seat similar to what your describing is often used in whitewater canoes and at one time was very popular in solo canoes. There is really no reason that you couldn't do this, but I don't think you will gain any strength advantages over hanging from gunwales. You may also add stiffness and pressure points to the floor of the canoe, which may create a situation that could cause extra damage from a collision that occurs on the bottom of your canoe.

Alan in Wisconsin

Post by Alan in Wisconsin » Mon Feb 21, 2005 4:09 pm

When you hang the seats from the gunwales, you generally use thwarts for stiffness in the canoe. I have a woodstrip canoe I made over 30 years ago, with seats attached to blocks epoxied to the sides of the canoe, and a single yoke in the center as the only thwart. At the time, I thought it might be a temporary installment of the seats, but they are still strong.

As far as I know, the main disadvantage is stiffness of the hull near the seat attachment block, so a rock that hits near that point in whitewater might be more likely to puncture. Since a rock is more likely to hit hard on the bottom, I put my blocks on the sides, not built up from the bottom. Both methods seem to work fine, but if the seats are to be high, near the gunwale, it would be simpler to hang them.

83glt
Posts: 36
Joined: Mon Jun 06, 2005 8:58 am

Post by 83glt » Tue Jun 27, 2006 12:08 pm

Hi there,
I've followed this thread and I guess my question is for the last poster who installed the seats 30 years ago by epoxying blocks to the sides of his canoe. Can you give instructions on how to install one's seats by this method, or at least direct me to somewhere that I can find such instructions? I'm just trying to build my canoe without the use of any bolts or screws whatsoever - just wood and epoxy. My canoe will not see whitewater, simply easy paddling on small lakes for fishing and camping etc. Thanks for any input.
Best regards,
Jason

User avatar
Patricks Dad
Posts: 1371
Joined: Wed Oct 13, 2004 1:11 pm
Location: Warrenville, Illinois

Post by Patricks Dad » Tue Jun 27, 2006 12:52 pm

We built our Redbird without metal. We hung the seats from the gunwales in the conventional manner but instead of bolts we used walnut dowels with cherry spacers and cherry wedges driven into the ends of the dowels (with epoxy of course). Plenty strong and looks great.
Randy Pfeifer
(847) 341-0618
Randy.Pfeifer1@gmail.com

Rick
Posts: 727
Joined: Thu May 27, 2004 9:23 am
Location: Bancroft, Ontario

Post by Rick » Wed Jun 28, 2006 8:24 am

Jason, you can use vertical cleats glued onto the sides, once you know how high the seats need to be. The station forms can be used as a template to determine the cleats' surface where they'll be glued on, and you can design some curves into the rest of the shape to match the canoe. They shoudn't extend too far down the hull, so that any object hitting the underside of the hull when paddling won't cause stress cracks because of the differences in flexibility at the edge of the cleat.

There is some risk that the cleat could cause stresses on the fiberglass sheathing and the sheathing could detach from the cedarstrips underneath, so IMO, a mortise and tenon type joint should be added in at the inwale, so that the cleat also hangs from that, with thickened epoxy.

Once the cleats are in place, then the seat needs to be built so that the four corners will fit precisely over them. You might want to recess the seat cross-members so that there's more area for a better glue bond at the cleat, and then reinforce with strips of glass to ensure the glue joint doesn't break with flexing as weight is taken on and off.

Good luck!

AlanWS
Posts: 209
Joined: Thu Mar 17, 2005 4:30 pm
Location: Shorewood, WI

Post by AlanWS » Thu Jun 29, 2006 5:14 pm

Jason:

I was anything but an expert when I hung the seats from blocks, just a high school kid who made a canoe. I needed seats, and that's the method I thought of. I decided where to put the seats, cut support blocks of sitka spruce, shaped them to fit the curve of the hull, and epoxied them in. Both mating surfaces were freshly sanded, and matched well. I probably used the hull as a sanding block to sand the support block to fit. The seats rest on the blocks. I don't recall what I did to fix the seats to those blocks. The blocks are something like 1" thick, 2" high, and I'll need to look to see how long. I don't remember whether each block is long enough to support the front and back of the seat, or if I have separate blocks at the front and rear of each seat.

Incidentally, I hung the seats from the gunwales in the canoe my son and I made a few years ago, and that's what I intend with the one my daughter and I are getting started on this summer.
Alan

BillB
Posts: 19
Joined: Thu Apr 07, 2005 8:17 am

Post by BillB » Thu Jun 29, 2006 6:32 pm

If permitted I have an off-topic question for Sedges. I too have a friend who weighs near 280 lbs. He would love to go canoeing with me but I am afraid my seats would not hold. I built Gilpatricks trapezoidal seats using 3/4" X 1 1/2" white ash. What seats do you have that supports your partner? Bill.

sedges
Posts: 290
Joined: Fri Jul 09, 2004 5:37 pm
Location: georgia

seats/big folks

Post by sedges » Fri Jun 30, 2006 9:18 am

Bill! My seats are standard size. 9.5 inches wide, rectanglular, filled area 15 inches(including cross pieces). I used 3/4 X 1 1/2 quarter sawn southern yellow pine, dense grain structural grade. Very nice stuff and as strong as most hardwoods. I used lap joints. Filled the seat without drilling holes or making grooves by using 3/6 braided nylon in a modified Belgian double chair weave.

I must admit that the seat flexes(sags) a lot when occupied by my 280lb partner, but it has never broken. In another canoe I have a sliding bow seat, which I highly recommend. This seat arrangement allow me to trim the hull with 280 or 160 pounds on the bow seat. If the other paddler is significantly lighter then me I move to the bow and let the lighter person take the stern moving the bow seat way back. Anyway, with the rails that the bow seat sit on being well inside the gunnels, the bow seat frame is much shorter therefore not showing as much flex.

BillB
Posts: 19
Joined: Thu Apr 07, 2005 8:17 am

Post by BillB » Fri Jun 30, 2006 10:53 am

Thanks Sedges. My seats are much larger and I drilled holes for caning. Not sure yet if I'll let my friend in the canoe - but it's good to know it's a possibility. Bill.

Post Reply