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Third Season Feedback (31/10/04)

This page reviews the durability of the lightweight construction techniques used when building a modified Huron Cruiser.

In summary, after three seasons of wilderness tripping I was very satisfied with most aspects of the construction techniques used, including the reduced fiberglass cloth weight on the sides of the canoe, softwood Sitka Spruce trim, the single gunwhale system, and a graphite bottom (for feedback on the latter click "Graphite Bottom" in the left hand menu). Hull design modifications were more difficult to gauge but the only thing I would like to change would be to lower the sheerline to design specifications. If building for mainly tandem use I recommend maintaining the original length, especially if you pack heavy.

Feedback topics:

Conditions of use

Fiberglass cloth weight

Sitka Spruce trim

Single gunwhale system

Design modifications

Conditions of (ab)use:

The conditions the canoe was subjected to were primarily wilderness tripping on Canadian Shield (rocky) rivers and lakes, often 2-5 days but also trips that lasted 2-3 weeks and day paddles. Most trips were paddled solo but there have been occasional tandem trips (more trips than are listed in the "Routes and Photos" section of this website). I did not treat the canoe gently - it has been my tripping workhorse. Landings were typically rocky and, while I did not approach shore at "ramming speed", the bow was often resting on the bottom when I stepped out. Class I-II rapids have been run and I have bumped the odd rock on those occasions. I paddled over beaver dams whenever there was a shallow channel, sometimes bottoming out and lunging my weight forward a few times to shift the canoe over the obstruction. When there was no channel I dragged the loaded canoe over beaver dams. I have also been accidentally lodged on shallow rocks in wavy conditions on Georgian Bay and bumped and scraped often (sometimes using the same lunging technique mentioned above to get off the rock). The canoe was stored upright on rocky ground during trips unless heavy rain or wind were expected. Sometimes the canoe was dragged while positioning it on shore. This was probably harder use than some people treat their kevlar canoes! The canoe was transported on the roof of a car using four foam blocks in the gunwhales and nylon adjustable straps hooked into a nylon chord in the painter holes. The canoe was stored in an unheated garage during winter.

Fiberglass cloth weight:

I built the canoe using 3oz RAKA fibreglass cloth. Both inside and outside had two layers on the football and one layer up the sides. Since I havenít built a canoe with the standard single layer of 6oz cloth in and out I am not qualified to make a comparison. But I can reflect on how this layup performed under the conditions described above.

Not surprisingly, given the conditions of use above, I have had to make repairs to the hull. The circumstances which caused damage included the following: rock impacts in rapids (2-3); tearing the seat out with my legs after a capsize while playing in rapids; stepping into or out of the canoe while beached (tandem use); and a crack on the hull after cartopping two canoes - the second canoe tied down with one aluminum gunwhale leaning against the side of my cedarstripper with padding (not a stress the hull would be exposed to in normal tripping conditions and not something I'll repeat). This may sound like a lot of damage in 3 years but bear in mind the canoe has had many encounters with rocks and even dropped on portage without damage. The outside glass was cracked or torn only two times. I have had more fiberglass cracks or tears happen on the inside than on the outside and on the occasions when the outside was damaged the inside was too, but not visa-versa (other than a scratch). This may be because the outside bottom of the hull has an additional 3 coats of epoxy from when I applied the graphite/silica/epoxy on the football area up to the waterline, thus making the outside somewhat stronger from the additional epoxy. But I also believe that when the hull flexes inwards the inside glass is more likely to crack and/or delaminate than the outside glass even if they had equal amounts of epoxy. Furthermore, I found the hull to be more susceptible to damage when tandem paddling than solo.

Inside broken plank repaired.JPG (57483 bytes) Rock impact in rapids - bottom inside - post repair.

 

 

Inside crack repaired.JPG (44718 bytes) Rock impact in rapids - tandem - side near bowseat inside - post repair.

 

 

post repair.JPG (38681 bytes) Same as above - outside - post repair.

 

 

outside crack.JPG (35783 bytes) Outside crack - cartopping two canoes.

 

 

Inside crack at stem.JPG (56322 bytes) Crack near bow stem - tandem - stepping in/out while grounded(?) - post repair.

 

 

Luckily repairs were very easy to do after having built the canoe. However, I have noticed a slight difference in colour where the repairs were made, perhaps because I used RAKA epoxy in construction and MAS (more convenient to obtain) epoxy for repairs. None of the repairs have rebroken or delaminated. Cracks in the cedar remain visible as black lines after repairs.

 

Sitka Spruce trim:

    Gunwhales

    Decks

    Seat frames

    Yoke and thwart

    Stems

The softwood Sitka Spruce trim (gunwhales, decks, seat frames, cleats, yoke and thwart) has stood up to 3 seasons well. However, next time I would coat gunwhales and decks in epoxy to give them a harder more abrasion resistant finish. And yokes/thwarts should be mounted deeper through the gunwhales all the way to the hull so that stresses are not on the gunwhales alone. All in all, softwood trim (and half the gunwhale material) are the most significant weight saving that can be made.

Gunwhales:

The gunwhales required frequent varnishing because the slightest crack or wear in the varnish coat causes the wood to discolour quickly from moisture. When I first built the canoe I stored it upside down in camp and noticed very quickly that the varnish would quickly abrade from the tips at the two ends. I now store the canoe right side up in camp to prevent abrasion to the gunwhales. Occassionally, if heavy rain or wind is expected, I turn the canoe over. And to better protect the gunwhales I have coated the tips in epoxy making a harder surface and they now stand up to inverting the canoe much better.

During a week long windy trip on Georgian Bay I found I was rubbing the paddle against the gunwhale for more leverage and the multiple layers of varnish completely wore off the gunwhale. I have since applied epoxy to the top and outside of that 4 foot section of gunwhale to make a harder surface that is more resistant to wear from the paddle. I donít typically rub the gunwhale with the paddle under normal conditions but paddling in wind all day is another matter. The epoxy was applied recently so it hasn't really been put to the test. Next time I would put at least a couple of coats of epoxy on the entire length of softwood gunwhales. It would add some weight but not as much as hardwood gunwhales.

Decks:

The decks have held up fine. Sometimes the varnish on the raised lip wears thin when storing the canoe upside down. This too could use an epoxy coat.

Seat frames:

The solo seat frame did crack during one violent spill in which my legs under the seat also ripped the seat off the mounting cleats as I was falling out (see also the Postscript at the bottom of the "Making seats" page via the left hand menu).

The seat frame was repaired instead of replaced and larger cleats installed and the seat frame mounted into slots cut in the cleats.

 

Previously the seat frames were epoxied to the top of narrower cleats with a bead of thickened epoxy, not a very secure method. The seat has also been mounted higher to give my legs more room underneath. Iíve had no problems with the seat and mount since. It holds my 210+ pounds no problem and it is a long seat frame. But the higher seat makes for a more unstable canoe when it is used as the bow seat while tandem paddling. Somewhere between the current set up and the previous one would have been ideal. That is the main problem with mounting seats on cleats epoxied to the hull: if you don't get it right the first time moving the seats is a big job compared to changing the length of hangers on seats hung from the gunwhales.

Yoke and thwart:

The Sitka Spruce yoke and thwart have held up fine. The only weak spot was where they attached to the gunwhales. The stress of picking the canoe up by the yoke caused the gunwhale  to develop a small crack.  Previously it was mounted via a small mortise and tenon joint and thickened epoxy. The yoke was remounted deeper into the gunwhale and against the fiberglass of the hull and this problem has not recurred on the yoke.

But it has occurred on the small thwart that replaced the stern seat. Another builder I know used the same single gunwhale system using cedar instead of sitka and he installed a single screw through the gunwhale and into the yoke to solve a similar problem.

The Sitka Spruce yoke itself seems sturdy enough but I am unhappy with the shape of the yoke on long portages, even though I hand carved it to custom fit the shape of my shoulders - or at least I thought I had. It is too narrow. A wider flatter design might be more comfortable. Next time I might consider buying a finished yoke and, if necessary, do some minor carving to custom fit my shape. Unfortunately, finished yokes are invariably hardwoods and therefore heavier (and harder to carve) but I have no problem with the overall strength of my narrow softwood yoke and see no reason not to use sitka again if weight is a consideration. The problem was in my design and not in the strength of materials.

Stems:

The softwood inner and outer stems have not been a problem. They are encased in fiberglass epoxy so they are at least as strong as the hull (stronger because they are 6 laminated pieces thick). The skidplates I added have held up well and have protect the fiberglass from abrasion (click on "Skidplates" in the left hand menu). Next time I might use only inner stems and skidplates on the outside.

Single gunwhale system:

The routered single gunwhale system - Sitka Spruce 1" x 3/4" with a 3/8" wide 1/2" deep groove routered down the centre and mounted on top of the sheer strip - has worked out well and is the single biggest weight saving. Double hardwood gunwhales are overkill in all but the most extreme use. The only drawback of the single gunwhale is they are too narrow to hang seats from. But the seats can be mounted on cleats epoxied to the hull (also stiffening the hull). I would like to try the routered single gunwhale system using hardwood (Cherry or Ash) for better abrasion resistance but I donít know if hardwood would be flexible enough to install using this technique. Steaming is not really an option because the thickened epoxy is put in the groove before final fitting on the hull and so the wood must be dry. Next time I would probably use Sitka Spruce again (for ease of installation and the strongest of the softwoods) but apply a couple of coats of epoxy before varnishing to provide better abrasion resistance.

Design Modifications:

I have not paddled a Huron Cruiser built to specifications so I donít know if shortening the design by removing the centre station mold and moving everything in 8 inches has seriously affected the performance of the hull. It feels a bit tippy and that may be because the widest part of the canoe was removed but I have become accustomed to the feel and I am comfortable paddling solo. It feels a little more tippy when paddling tandem but that is also a seat height problem.

I pulled the gunwhales in about 1 inch to give it more tumblehome and a rounder bottom and that also contributes to the tippy initial stability. But the canoe has good secondary stability up until the tumblehome is reached. It is not possible to tilt the gunwhale all the way to the water ĎCanadian styleí but it can be leaned quite far and it handles well in waves.

The sheerline is higher than spec by about 1 inch. I wanted a dry boat in waves but I soon discovered the Huron has plenty of freeboard without the additional inch. Paddling in wind can sometimes be a challenge. If the gunwhales ever need replacement I will lower the sheerline to decrease wind resistance (also reducing weight).