Sunday, June 13, 2010

Adding An Extra Seat to Your Canoe

Here's a simple way to add a third seat to your canoe.  Why you'd ever want one is something of a mystery to me, though if you only paddle quiet lakes with an extra kid in the boat, this might be useful.  The problem with a third seat is that it puts the weight of the extra person a bit higher in the canoe than if that person were sitting on the bottom.  The higher the weight, the more tipsy the canoe, but if you've got a bit boat, this extra seat should give your middle passenger a high enough position that he or she can paddle comfortably rather than sitting in the bottom like a big sack of rocks.

Take out the center thwart so you'll have room for the seat and your legs.  You'll want the weight of the third seat passenger balanced at the center of the canoe.

Drill holes for the screws that are large enough for the 4 inch long sheet metal screws you are going to use. Make sure they are the same distance apart (7 inches for an 18 by 10 inch seat. These holes will allow you to screw into the center of the hardwood dowels.
You can use 2x2s if you stick with hardwood for strength.  Use a 1 to 1-1/2 inch hardwood dowel otherwise. Use screws with washers to fasten the dowels. in place.  The washer distributes the binding force across more hull area and reduce wear and potential damage to the hull.

Dab a little epoxy or butyl sealant on the ends of the dowels and position them so the holes are at the center of the dowels. When you cut the length of the dowels, make them as exact as you can.  You don't want them to push the sides out or pull the sides in and distort the shape of the canoe.  Predrill holes into the ends of the dowels once they are in place.

Dab a little butyl rubber sealant over the holes and then drive the screws into the ends of the dowels to hold them in place.  If your canoe is aluminum or wood, you should have plenty of side strength to handle the weight on the seat. If you've got a plastic, fiberglass or composite boat, you may need a brace.  more on that later.
The half inch marine plywood seat should be at least 18 inches wide for comfort if you have that much width to work with. If you don't you should really rethink adding another seat cause buddy, if your boat is that narrow, you are going over if you add more weight that high in the boat.  Use a router to round the top edges to avoid splintering and chafing you skin when you sit on it.

Turn the seat over and screw 1 by 1 strips to the front and back edges of the seat (the long sides).  Glue them down first, then predrill and add 1 1/4 inch screws along the length of the strips.

Once you get all the screws into the 1x1 strips, use the router to round the edges so they won't chafe your legs while paddling in the kneeling position (which you should if you've got a third paddler.  It keeps the weight of your legs lower so the boat is more stable.

Set the canoe seat over the top of the dowels.  The two 1x1 strips should fit snugly outside the dowel to prevent fore and aft movement of the seat.  This view shows the dowels without the canoe.  Of course, when you do this part, you've already got the dowels in place across the gunwales.

Once the seat is in place, Drill holes through the seat down into the dowels.  Don't put more than about 5 holes into the dowel to avoid splitting or weakening them.  Screw 3/4 to 1 inch screws into the dowel to secure the seat in place.  Use butyl sealant in the holes before you drive the screws in to seal them against water. Then stain and apply 3 to 6 coats of marine spar varnish to protect the wood from getting wet.  If you want to be especially thorough, varnish the dowels and seat separately before attaching them.  You'll have better water protection that way and the seat will last for years and years.

If you're afraid your boat won't be able to handle the weight on its sides, especially for light plastic, fiberglass or composite boats, add a center support by simply cutting a 2 by 6 and setting it lengthwise under the center of the seat.  Screw the top end in place through the seat.  Attach the lower end with epoxy or, if the canoe hull will accept fiberglassing, just fiberglass the entire support and base to hold it in place. If the canoe is fiberglass, you can always fiberglass the entire seat assembly and glass around where it attaches to the hull to strengthen the seat.

This, will of course, increase the weight of the canoe, but if you've got one big enough for a third seat, it may not matter much.

A third seat may be just what you need for paddling around the old pond. I wouldn't want to use one in whitewater, but not everyone does rough water anyway.  A canoe rental on a quiet lake could probably add seats like this for the comfort of those threesomes that want to take out a boat and not have someone get his or her butt wet by sitting on the floor of the boat.

Also, this seat design works if you want to replace an uncomfortable seat or add a seat to a thwarts only canoe like the one I learned to paddle in at summer camp.  

Have fun and remember.  It's your boat. Do what you want to it just so you don't sink her.

Tom King - Tyler, TX


  1. thanks Tom. great plan. what diameter of dowel do you suggest? I presume 2 inch, per your 2x2 comment.

  2. If you're using hardwood dowels, use a 1 to 1-1/2 inch dowel. Two-by-twos are actually only 1-1/2 by 1-1/2 inches.

  3. Why would anyone wish to butcher their canoe to accommodate such a dreadfully designed worksheet for a botched job is a mystery. It would appear that the 'author' has not the faintest idea about outfitting canoes. There are plenty of good canoe sites that offer excellent advice on adding an extra seat to a canoe......look to them for good advice

    1. What a jerky comment.... As my dad used to say "if you don't have anything nice to say, don't say anything "

  4. Someone asked me for a homebuilt solution to adding a third seat for a kid. Not everyone treats their canoe as a work of art. Some of us use them to get our kids out on the water and we make do with what we have. The seat, as designed can be stained and varnished to look nice and the seat works great for paddling around the lake with little ones. When you have a stable of 8 or 10 working canoes such as I have managed during 40 years as a canoeing instructor, you often make do with what you have. This worked for us to replace a center thwart in an aluminum canoe after a sailboat ran over the middle of the boat the season before I took over the canoeing program. If you want to buy a manufacturers replacement seat, that's great too. This we made of scrap materials we had in the shed and a couple of store-bought hardwood dowels. We wanted it to be extra strong because of the poorly done heli-arc welding on the tear in the gunwale.

    Not everybody can afford to run down to the canoe store, order parts and wait six weeks for them. Sometimes you make do in order to keep the boats on the water. In this case we had blind campers coming and we needed something with an extra seat so the kids didn't have to sit flat on the bottom. Some of them are disabled as well and have difficulty getting in and out of the boats. This repair served two purposes - access and strength.

    I appreciate your concern for the canoe purists out there, but an anonymous snotty post is kind of in poor taste. No one who has an expensive canoe is going to be interested in making this type of addition. They'll get their local livery to do the work.

    Sorry for the irritation, but I've seen you guys paddle past us on the rivers and lakes with your noses turned up at my kids in their rag tag donated canoes. I make them as safe and sturdy as I can with the funds our youth program has at hand. Tell me which kid I should leave behind until we can "do it right".

    It's just a boat. Once I get them, I teach the kids to take good care of them.

    Hope that answers your "Why would anybody do this?" quetion - that's why. Next time include a link to a website showing "the right way". Part of the reason I wrote this was because nobody had any plans for replacing a thwart with a seat posted, so I posted my solution. Got something better, then take the time to help people by posting your own solution.

    And by the way nobody botched the job. It worked pretty well and looked nice (I recessed the screws and covered them with little metal disks I hammered into the holes. The seat lasted for years. The boat still has the rig set up as far as I know.


  5. I agree with Anonymous. Tom, you are entitled to do as you wish with your own canoe, but if drilling through the hull is the best solution you can offer for installing a seat, you really should not be advising others.

    Best wishes,

  6. Again, if you have a better solution, please offer a link to it. In the meantime, as I explained above this was first done on an aluminum which had been run over, the hull torn and it already has holes drilled in the hull. Not all canoes are sacred objects. Some work for a living and depending on how they are used some screw holes probably won't be noticeable - especially for one that bumps around the lake with kids mostly. As you say, Michael, it's our own canoes. I have a canoe myself that I would never drill a hole in. I also wouldn't install a third seat in it or any seat for that matter. It has thwarts and that's all it will ever have. It's a classic and I will leave it that way. On the other hand I have two or three old knockabouts for the kids. Some have been repaired with duct tape and glops of epoxy. They get just as much use and actually more than the holy wood-canvas one.

    I was asked to offer a solution for adding a cheap homemade seat to the second type of canoe and here it is. I wouldn't dream of doing this to a pristine wood canvas, cedar strip or expensive racing canoe. You have to use your head.

  7. Tom
    I would like to thank you for your post. My dad just gave me and my kids an old beat up canoe aluminum canoe and it doesnt have any seats at all in it. For one, I dont have the funds to purchase seats specific to it, which would cost over 200.00 (per multiple sites online). Secondly, why would I want to spend 200.00 on an old beat up canoe - as long as it gets my kids and I out on the lake to fish and paddle around, that is all that matters. We have made a project out of it and are repainting it, fixing the dents and are going to utilize your seat design to add seats.

    Thank you for your design, time and your heart that you are pouring into these children you speak of.

    God bless,


  8. You're welcome. Like I've said before. This works great for an old beat up aluminum canoe or a plastic canoe. It's a fairly cheap solution. You can get the special add-on kits from canoe companies, but they do run some serious dollars and, if you've got kids, you probably have more time than extra cash. This looks pretty good when you're done with it and holds up to the kids' abuse pretty well. You don't want to leave your boat swamped to the gunnels and floating in the swimming pool a lot or the wood will deteriorate, but if you take reasonable care of your boat, this solution can add years of usage to an old boat and give you're kids a place to sit up off the bottom (which will have water in it whenever you have kids or amateur paddlers in it). There are boats which are works of art or racing boats and there are boats that are for fun. These seats are for the fun boats.

  9. Here's a neat removable "low" seat design I found on Youtube.