does fresh v salt H2O affect performance

Paddling in the local lake today, I wondered if a given boat will paddle noticeably different (to the discerning paddler) than the same boat in the ocean. The difference is buoyancy is slight (about 2.7%), but that should mean that less of the hull is in the water). Also, salt water feels more viscous to me. Not sure what difference that would make or if its just my imagination. There actually is a practical reason I’m wondering. I will be demoing some boats soon and have prepared an objective set of measurements to make. I will be doing all boats at the same place and time, but today, demo’d the measurement sheet with my boat in the local freshwater lake. The others will be evaluated in salt water.


doubt it
I doubt you’d notice a difference. But lets look at the physics of this…



True, salt water is heavier, thus it may seem to ‘slow’ the canoe down. But, you’d make up for it during a paddle stroke since your paddle is pushing a heavier water. Also, since the water is ‘heavy’, your canoe does not sink into it as much. In other words, if the canoe’s water line is 4 inches in normal water, in salt water it may be less. So, that being the case, it may be easier and faster to paddle it.



Let us know how it goes.

I’ll quibble about that

– Last Updated: Jul-14-14 1:24 AM EST –

I have no idea if there's a difference between the two types of water that is noticeable in terms of boat performance or travel speed, but I'll argue against one of your points. You say that if there's more resistance to the boat moving through denser water, that will be made up for by the paddle moving a volume of water that's proportionally heavier too. Well, that sort of makes sense, but don't forget that what really matters is how much force you can apply to the blade as you pull on the shaft. Without switching to denser water, you can still increase the force applied to your stroke. Yes, the paddle will slip more when you do, but that applied force is what matters most. In fact, there's only so much force you can apply, at least when it comes to doing so repetitively for long periods of time. If you can apply, say ten pounds of propulsive force with a given amount of muscle exertion, the same force applied to the paddle in denser water will only mean that the paddle slips a tiny bit less, so maybe the net effect would be the same as a very slightly longer stroke, but that's all. There's still only ten pounds of propulsive force. So, since switching to salt water won't change how hard you pull on the paddle, and how hard you pull on the paddle IS your propulsive force, the propulsive force should work out to be just about the same (we aren't machines that will move the paddle exactly the same distance, at the same speed, even if the paddle "has more to push against"). It may not be totally that simple, as the tiny difference in slippage may complicate things just a little, but no matter what, it's your own applied force on the paddle that controls how hard the boat is pushed.

The other complicating factor, as you mentioned, is the fact that the hull will sink less deeply into denser water. That should do *something* to counteract the fact that heavier water is being pushed aside as the boat moves, and in fact, the weight of water that gets pushed aside will be the same, but the surface area of skin friction is less. On the other hand, the friction per unit of area may be greater. Lots of things going on, though I expect each effect is minor.

I have no idea how all this will work out in the end.

I have been paddling kayaks
in lakes and in the ocean for over twenty years, and have never noticed a difference.



jack l

Might fit in the category
of thinking too much? Time to go paddling.

I feel it
By far, most of my paddling is in fresh water, but when I do go to the salt, I can feel the difference; the boat seems sluggish.



This subject has been discussed here before and some others also at least had the perception that salt water feels slower. One thing is for sure, salt water is messier.

fish on
well done.

Pesky salt…
Salt definitely slows you down…

That’s why racers at Bonneville Salt Flats are “so damn slow”. :^)



Seriously, I have no idea; I never paddle on salt water. In my opinion, perhaps 1 of 50 paddlers could

truly discern any difference in boat speed, and 1 of 1,000 paddlers would care about the difference.



BOB

another complicating factor
tidal currents. It’s hard to find salt water that is tideless. Not too many of us get to paddle the Dead or Caspian Sea.



http://education.nationalgeographic.com/education/encyclopedia/sea/?ar_a=1

Drinking salt water slows me down.

Maybe Great Salt Lake or Mono
I’ve paddled both,no noticable difference from fresh.



and yes you used to bob like a cork in the Great Salt Lake (much denser than seawater) when I was a kid.

The Ocean
has all different salt levels depending on the location around the world.

I can’t tell a difference paddling or rolling salt vs fresh…but the fresh is drinkable and the salt does away with the need for a Netti pot.



Best Wishes

Roy

the nose knows
It is surprising to me how poorly I tolerate a snoot full of freshwater when rolling, but don’t mind sea water at all.

Bald or hair?
Yeah this would probably fall along the lines of,… “will I paddle faster with a bald head or a head with hair?” Might give the nod to baldie but certainly not noticeable,… maybe by a hair!

water
The bigger impact is if its daytime or nighttime.

mor water
The gravity effect of the sun slows you down. I always go faster in the dark.