Gunnel size

[Ben Mahaffey]

I am slowly working my way to a finished canoe (freedom 17) and have gotten to the gunnels. I will do scuppered gunnels with a capped outwale, thinking about 1/2 think (not including the capped portion) but wondering what most people are using for depth of the gunnel. My plan was to have 1/4 capping the hull.

Also if anyone has a different idea I am all ears! Using cherry for wood to keep weight down, if that matter for any of your ideas

Ben

 

[Jim Dodd]

Great idea to cap the gunnels ! Been doing it for years. I glue and screw the inwhale, and glue the outwhale. This to me gives the strongest combination, and best seal.

Capping, seals out all moister, saving the gunnels from replacement in short order ! I've replaced enough Bell gunnels, because they weren't properly sealed..

I use Ash, which is a little tougher in the durability department, than Cherry.

For a tandem, I like beefier trim. I would consider 1/2" minimum for the outwhale.

I also like scuppered inwhales ! 3/4" x 3/4" with slightly over 1/4" scupper gap.

You can use thicker gunnels depending on your use and like !

Certainly others will have ideas.

Looking forward to pics !

Jim

 

[Cruiser]

At this point you have to think about how you intend to use your boat, trim IMO is the one place where a lot of unnecessary weight gets added to the boat. Gunnels in particular get overbuilt for purpose, with the associated weight gain that goes along with the extra wood.

I trip with my Freedom 17, so weight was a consideration for the build. As far as scuppered gunnels go, they look nice and traditional, but IMO serve no real purpose on a modern tripper, a simple bevel on the inner gunnel will let water out just fine. Capping again looks good, but serves no real purpose from a serviceability PoV .... personally I like the contrast that the hull core makes between the cherry gunnels. I seal the gunnels with epoxy, so there is no issue with water infiltration.

I used 3/8" x 3/4" strips, with a 45 bevel on the inner gunnel, the tops where rounded over (think 1/4" radius) ... these have proven sufficient for task and there is no flexing or other signs of weakness .... you could use this as a reasonable minimum starting point.

Since you seem somewhat weight conscious, lets do a little exercise calculating the weight of 3/8" x 3/4" versus 3/4" x 3/4" gunnels. I will use the density value of 35 pounds/cubic foot for cherry from the Wood Database .... calculate the area of the gunnel (thickness x width) and multiply that by the 4 lengths you will use, convert that volume to cubic feet and use the density to determine the associated weight. The 3/4" x 3/4" yielded a weight of ~9.3 pounds, this does not include the material for scuppering .... using 3/8" x 3/4" comes in at 2.3 pounds, for a net difference of 7 pounds. It is important to keep the weight cost of trim decisions in mind when making those decisions.

EDIT: As Alan notes below, I made a mistake calculating weights, it's 9.3 vs 4.6 pounds for the gunnel weights, leaving the original post intact, so that the posts make sense to anyone reading them. Brian


The decisions you make on the trim have very significant impacts on the final weight, the example above is just for the gunnels, you still have decks/seats/thwarts to consider.

This is a link to my Freedom 17 build, you can see the gunnels in a few of the final pics :http://buildersforum.bearmountainboa...=2244&start=15

Hopefully, some of these thoughts will be of use.

Brian

 

[Alan Gage]

The 3/4" x 3/4" yielded a weight of ~9.3 pounds, this does not include the material for scuppering .... using 3/8" x 3/4" comes in at 2.3 pounds, for a net difference of 7 pounds. It is important to keep the weight cost of trim decisions in mind when making those decisions.

Maybe I'm just overlooking something obvious but shouldn't the 3/8" gunwales weigh half what the 3/4" gunwales do?

Alan

 

[Cruiser]

I think you are right Alan, I will correct that when I get back from the dentist, TY

 

[Jim Dodd]

I would be lost without scuppers ! Having built every canoe with them.

I attach a multitude of things to my inwhales, using bungee cords with ball locks.

Fishing poles, umbrella, yes That's right UMBRELLA ! A Nate stick, I tie my fish stringer, I can attach a camera easily, as well as almost anything else.





Securing things to the inwhale is one thing, but I hang my seats from my inwhales, and the spacers allow me to do this and still reduce the weight of a solid inwhal, and still have enough wood to support my weight at the critical spot..

Every builder has his or her likes in how they trim a hull. I respect that ! The above is just how I like my inwhales !



Jim