Making a slat seat

[Howard Caplan]

I posted on another thread that I will make slat seats for my newly built Prospector. Somebody warned of the strength of the seat based on the span of the width.
I have cut and shaped the slats out of walnut and the brace out of ash. The spans I am looking at are about 34" at the longest. I have cut the slats at 15".

My first question, should I make the seat slats longer to better balance the full width and would that strengthen the seat?

Second question, which wood is stronger for a length like this, walnut or ash and should I increase the thickness of the brace wood to about 1.5" instead of 15/16"

Thanks for replys,
Howard

 

[Fitz]

Prospector Bow Seat.

Howard:

Here is the bow seat out of my 17 foot Prospector. The longest dimension is 28-1/2 inches, the shorter length dimension is 25-1/4 inches. The slats are ash and are 7/8's inch wide and 1/2 inch thick. The main supports in the middle of the seat appeared to be cedar to me. I made a replacement with ash for the one my fat butt broke after falling on it in the rip. The angled edges of the seats are 1-1/16 in wide and 1/4 inch hardwood.

 

[Howard Caplan]

Thanks Fitz. I see this going full width. I was thinking shorter width for the seat with ash spans completing the width of the boat. That's when I realized I had possible structural problems and less ability to get tight to the walls of the canoe to heel into a lean.
Because my wife wants a lot of leg room and I want to be able to turn the boat around for solo paddling, I am moving the bow seat back a bit to give me a 33 - 34" span in the bow while the stern seat will be set back a bit further.
What is the drop length from the top of the gunwales to the top of the seat?
Howard

 

[Fitz]

Prospector Slat seats

Hi Howard:

I found a picture of the Prospector showing the seats. Do this photo and the photos above give you enough to go on? The bow seat is hung from the inwales using carriage bolts and dowel spacers that are about 1-7/8's inches long (bottom of inwale to top of seat). The stern seat has longer spacers in the rear to account for the sheer and to make the seat level.

 

[Howard Caplan]

Thanks Fitz. The other thread post, the seat looked different from the other pics you were so kind to send. This one too is newer and has a bit more shape and style to it then the older canoe seats with the originals.
All will come together this weekend.
BTW - Jamestown finally shipped the Sea Green and I have one finish coat on and the seats will be made while the next several coats are setting up.
howard

 

[Howard Caplan]

The slat seats are finally built.
But, I made a stupidly bad cut on both my length of walnut and ash that left me with not enough length for the second seat. So, I went to my local hardwoods store and bought "shorts" of both woods spending $11.00.
Got the planks home and milled them. It was then that I realized the ash was still wet and probably green.
I now have 3 ash slats in the seat that are probably too wet. I want to varnish and get this boat in the water but I paused over the weekend when I realized, the varnish may not take to the wet ash.
Is there a sealer to use that will will allow varnish to go on? Or should I find a properly dried length and re-do the slats?

howard

 

[Denis M. Kallery]

Howard,
Years ago when I took classes from Michael Dunbar on Windsor Chair making we dried the spindles in an oven set on warm. I think it took overnight. Don't recall for sure.
Good luck! Denis

 

[Howard Caplan]

Dennis.
Reading your post was a EUREKA! moment. Or a duh! moment because I should have thought of it.
Unfortunately, the two long slats do not fit in the oven.
I've had the pieces outside in the sun and breeze for the past two days and they seem to be lighter today, so I may be getting somewhere. I may install the seat without varnish and then sand and varnish in the fall.
Thanks,
Howard

 

[Andy Hutyera]

Another chair maker's trick is to enclose the wood in a cardboard box with and incandescent lamp. I used this trick to dry the spindles of an arrow back settee I made. It works quite well and doesn't take very long. If you have a moisture meter you can check the material for dryness. If not, if you have a small scale you can weigh a piece. When it stops losing weight, it's dry.

 

[Pernicious Atavist]

Man, that looks mighty uncomfortable. Are you using it because it was original to the type, of for some more functional reason?

 

[Andy Hutyera]

Ed,

They only look uncomfortable. My 17 ft Prospector has them and they flex enough so they are no problem to sit on. They have the advantage of not breaking or getting brittle like cane. Now if the slats ran the other way,it might be a different story!

 

[Pernicious Atavist]

Thanks, Andy. Without trying one out, I'd have second thoughts about spending the day on one. I just built a front seat/master partner for mine and caned it [first time doing that], with the small plastic seat webbing, which worked great! Still, I'm sure my bikini-clad crew would prefer web to slats....

 

[davelanthier]

Actually the Chestnut Prospector style seats are quite comfortable. Since this was originally designed as a heavy duty working canoe the components had to be strong and reliable.

 

[Pernicious Atavist]

Makes sense. Toughness first.

 

[Howard Caplan]

I had two rationales for building slat and not cane. One is, I am a kneeler and I use little of any seat - just the leading edge to brace my butt and the other reason is, I never liked the look of cane and find it weak - oh, plus I have no patience to weave the cane and I wanted everything wood and structural to be built by me - I even made my own seat spacers.
I don't expect these seats to be less comfortable then anything else. I think the biggwest drawback to slat is the additional weight.
My lovely and talented wife, on the other hand, already has her seat cushions lined up for our maiden voyage - this Sunday (hopefully - need a low humidity day for some varnish). But she likes seat cusions for cane seats, too.
Howard

 

[Mark Riffe]

Well, I see that I'm only 14 years late in adding to this thread, but here's another take on slat seats in case someone is looking for options.
After buying a used canoe with unusable seats, I set about replacing them. Having seen slats seats on other canoes, I tried the same, first on a set of camp chairs to test the design and then the canoe. The width of the forward seat adds to its comfort in the give of the frame, but the slats themselves seemed less than ideal—something about my hipbones riding on the same slat. Mimicking camp-chair evolution, I turned the slats 90 degrees (front to back) and thinned them down to have their own 'give'. Between the two, the forward seat was a success, angled slightly downward for kneeling but flat enough to sit on to relieve my knees. The slats are laced onto the frame to afford flex without the prospect of screws pulling out. Photo attached.
The rear seat is another matter. The narrow frame doesn't afford much give and the slats felt hard, even oriented front-to-back. The solution was to steam-bend the slats to conform to my anatomy. The slats are white oak for durability, 1/4-inch thick and thinned slightly at the front to avoid pressure on the underside of my thighs when kneeling. The seat feels soft both front-to-back and side-to-side when bracing. Slats are laced on separately and spares attached under the seat in case of breakage. Tests are ongoing. Photo attached.
I have also tried sling seats (no give once weighted) and others' woven seats (cane and webbing), which do not support a kneeling position well and eventually sag into discomfort over time when used "upright." For long-term and extended use, slats seem to be the best option for me.