gas mileage with canoe right side up

I know most people carry their canoe upside down on a roof rack. But the air flow bounces off the windshield and hits the canoe’s inside as it travels. I assume it creates quite a bit of drag. I wonder if anyone carries their canoe right side up and sees any gas mileage improvement.

some things just aren’t worth it
Hauling a canoe rightside up for any considerable distance introduces issues that just aren’t justified by a tiny potential fuel saving. But, maybe when gas hits $25 a gallon I’ll think differently.

I see it a different way
You know how one of the best ways to improve the aerodynamics of a car is to lower it to within a few inches of the ground, so you substantially reduce the amount of air from flowing past the underside of the car? I figure the same goes for canoes on your roof. I think putting the open side in close proximity to a solid surface does more to decrease drag than dealing with that little upward wind coming off the windshield. Think about how one-half to two-thirds of the open side of the boat is within the wind shadow of the car when the canoe is upside down (depending on just where on the length of the boat the wind-shadow effect kicks in), but when it’s rightside-up, 100 percent of the open side of the boat is exposed to your slipstream. Also, it might even be better for dealing with that upward blast of air to have the canoe upside-down, because you don’t deflect that wind sideways so much once it reaches the roofline. Just a thought. You’d have to verify this with testing, but like Clarion, I wouldn’t rack my canoe in a way that’s likley to damage it, or make a rain cover necessary, or at least make the job much more difficult and expensive than it needs to be (imagine the complexity and cost of saddles which closely match the hull shape of each type of canoe for us multi-boat owners).



This reminds me of the old idea that putting the tailgate down on your pickup truck reduces drag. I always doubted that that was true after watching swirling leaves and debris in a truck bed, and sure enough, some graduate students at M.I.T. did some testing that shows the drag is significantly less with the tailgate up, not down. Things aren’t always as simple as they appear.

But mesh is better yet!
Your comment about the tailgate got me to remembering when they tested that on Mythbusters. They found that having the tailgate UP is better than having it down, but then later they tested using a mesh tailgate and found that to be even better than using the tailgate up. I suspect it had a spoiler-type effect and reduced the vacuum drag behind the tailgate.



I suspect the air moving under the upside-down canoe is simply funneled to the back of the vehicle with no real ill-effect - unless the back of the canoe is somehow blocked.



I wonder if anyone has made a canoe cover and tryed cartopping with that on. I would think that the upward flow over the windshield would be hard on the cover.

Sure hope it dun’t rain…
FE

Come to the light, my brethren!!
I wonder if anyone has made a canoe cover and tryed cartopping with that on. I would think that the upward flow over the windshield would be hard on the cover.





Um, I think they already have. Only, they call them KAYAKS.



YMMV

I haul canoes on my truck
bagged in covers from the Bag Lady (they are tight fitting but there is a small opening in them on the inside hull side).



Have Yakima hight towers, because of the sheerline of the boats and their short length. I truck top with racks on the cap only, not the cab due to twist of cap and cab on logging roads.



Thats a recipe for bad gas mileage right?



Nope. 21 mpg on my big V8 with or without canoe.



Its all at highway speeds and I suspect a big motor works less hard.



Open end up would be sure to break some boats that are unsupported in the middle. Sooner or later its going to rain… you can do this with yaks with snug cockpit covers but try finding a neoprene cockpit cover for your canoe!

…the rooftop windvisor? here works!
Took my rooftop windvisor? off my Xterra years ago, but I think here is where those things work, however I think there is an increase in mileage without them on the whole, so if one wanted to work with a little differential calculus…here’s the place. With my OC-1’s rocker…my guess is that there isn’t much air collecting. It’s a 9’10" boat…front airbag in, add the pedestal…and there isn’t much area for the air to funnel into. I think for a flatwater tandem there might be some drag…but how much is a mystery to me.

Pick up with racks

– Last Updated: Jun-23-08 2:30 PM EST –

I keep the front of the canoes behind the airstream. Actually did 75 mph coming home one day with the canoes going down a mountain.15 miles total. Got home and found the straps for one canoe were in the bed....'CUZ I NEVER STRAPPED THE THING DOWN!!.

Rain
Rain is what I’ve always thought about.

Besides, my old 17’ Grumman probably looks better

riding upside down.

Hell, I guess old Grummans probably look better upside down in the river.



jerry

Gravity, inertia,
Are laws of nature. So is: canoes bottom up, kayaks bottom down. It’s the way God intended them to be carried. Do it backwards, face the consequence.

Psalm #???

– Last Updated: Jun-23-08 2:15 PM EST –

I think there is a Psalm about that somewhere in the Bible, but I can't find it.

Amen!

– Last Updated: Jun-23-08 3:20 PM EST –

Kin' we git an Amen here, Brothers an' Sisters?

"Canoo unto others as you would have them canoo unto you."

Amen!

"And The Lord sayeth onto Noah - "Hey buddy, sure hope you got a pfd for everyone onboard?" And Noah casteth down his head down in shame and giveth over the holy fine of 250 pieces of myrrh and frankincense to the Marine Police Archangel".

Book Of Bubba Chapter 57 Verse 13

Rev. Fat Elmo