How much much weight would be lost by cutting down a kevlar canoe(no gel coat) 2"? This would be an 18’ canoe.
Tell us how much it weighs right now
Knowing the starting weight will help anyone who can provide a good estimate, since not all Kevlar hulls have the same weight per unit of area. The more the boat weighs right now, the more weight will be eliminated when you cut down the sidewalls. Whether the predicted loss is worth the trouble will depend on your needs.
Cutting Down Canoe Weight Reduction?
Current weight is 56 lbs
in limited cases, it may help, but in general this is a serious undertaking that should not be your first foray into serious boat modification.
it would help to know what boat it is.
You have some issues
First reducing freeboard compromises safety. You will have to lower the seats dramatically
Also stems and bottom have a thicker lamination schedule. There is more fabric there. More layers
Sidewalls are usually thinnest
Buy another boat if you want light. That weight is not unreasonable for such a big boat. my Souris River comes in at that weight. It's an 18 footer
The canoe is a Sea Clipper. The modification would be at the factory during production on the Kevlat Ultra-Light. The canoe is very deep at 23-15-21
Here’s a shot in the dark with large ‘error’ since it treats canoe as homogeneous object…see note at end.
56 lbs/216"=0.25 lbs/inch
Cut off 2"*18’=36"
36"*0.25 lbs= ~9 lb weight reduction.
NOTE: Since you won’t be removing the ‘heavy’ stuff like gunwales, seats, bottom (denser/reinforced) sections…it probably more like half that calc…maybe 4.5 lbs?
Have you asked Marlin Bayes?
He might be able to give you a better estimate than anyone here.
I wanted a little larger canoe than my MNII in terms of room for the front paddler and more space for a growing 3 1/2 yr old. The Sea Clipper is a Jensen design as well.
Is it practical to take a canoe that was designed for a specific use and modify it to meet my needs?
15 inches is not overly deep for an 18 foot canoe
The Souris River Quetico 17 is 13.5 inches deep
My Wilderness is 14 inches deep
There is not much to be saved in an inch of shaving. With an active kid. Well I am not the parent
Need lighter pick another boat and move the seat back if necessary. There are ways to adjust room and trim
In your case
with the additional info, I'm all for it. Alan Gage cut down his wenonah wwc1 by 2 inches because it was so deep and he reports good results. I have also heard of wenonah reducing the depth an inch or 2 at someone's request.
unless you will be on very large water or you are very heavy, you don't need a 23/15/21 boat. 1-2" shorter will be an improvement in wind and weight.
I say do it
I think it is a terrible idea. It is better to get a different boat. Fifteen inches is the standard depth for a river boat. Some are 16 inches or more.
I have an OT Guide 18 in cedar and canvas. I would give anything for it to be 15 inches deep. It is 12 inches and lacks freeboard with a load for a week.
I have cut down several royalex boats for various reasons and one fiberglass one but royalex thickness weight loss was more significant than it would be in a kevlar canoe. The top edge is very thin on a kevlar canoe so I would guess no more than 2-3lbs would be lost for a two-inch cut down. NOW,… if your main reason is to alter the design/purpose/characteristics of the canoe to better suit your needs, go for it! Just don’t expect two inches off the top to make any discenrnable difference in weight!
I have cut down
one 16' royalex explorer, a Kevlar 18+ footer, and a fiberglass 16 footer. One inch each. And three strip boats from 1.5 to 3". In my opinion you will be lucky to gain 1.5 # per inch. The girth of the boat is about 55". If the layup was consistent that's about 1# per inch (one inch off each side=2# ). But the high freeboard is thinner and lighter. So you are unlikely to get that much.
You will not change the stability of the boat, you can have the seats at the standard height. The boat will be noticeably less wind blown but wetter in big water. Wenonah marketed the Whitewater II at 13.5" deep for lake tripping and citizen racers (later dubbed the Minnesota) but they also sold a "High-sider" 15" deep for the down river racing customers. I have ended up around 13.5" on our tandem canoes.
All of my cut-downs but one were made to get under the wind. And it worked. I cut the royalex boat down to reduce weight (4# at most) and made a cloth spray deck and belly cover for it. I have questioned the wisdom of that move on the few occasions we have used it in bigger white water.
Unless you are running heavily loaded or big white waves, you are much more likely to be plagued by the wind than to swamp the canoe. My 2 cents.
I think your calc
Drains, with respect, I think your calc is per one inch of boat length not inch of freeboard. And yes if you cut 36" off the end of the canoe it might weigh 9#.
The Sea Clipper dimensions are extremely similar to the Jensen WW X another downriver racer. If it is a repurposed downriver boat of the WW X generation, it will have little if any more volume than your Minn II and might be less stable.
The Minn II is a little leaner above the waterline but at the waterline it is an inch and a half or so wider. While the original Minn was a cruiser class (32") waterline like the Sea Clipper, the current Minn II was widened to make standard class (33.3") waterline.
If you haven’t already, you might want to paddle a Sea Clipper before you make the leap.
Yes I agree 100%
Right on PeterJ! Everything you mentioned mirrors my experience and calculations. BTW, I love the Yellowstone River too. Yankee Jim canyon outside the park is alot of fun!
in ultra light
Bills Bags n off you go !