Rain water as lubricant

[Top cat]

We have noticed that passing boats go past much more quickly when it's raining. So could it be that rainwater acts as a lubricant speeding their passage ?http://www.canalworld.net/forums/public/style_emoticons/default/closedeyes.gif

 

TC

[PaulG]

We have noticed that passing boats go past much more quickly when it's raining. So could it be that rainwater acts as a lubricant speeding their passage ?http://www.canalworld.net/forums/public/style_emoticons/default/closedeyes.gif

 

TC

Wrong.

It's the additional water vapour in the atmosphere that causes the engines to develop more power, IMHO.

[Higgs]

It might be the same brain cells working that make you want to run to get shelter. A little tweak of the throttle to speed up a little. ??

[Ray T]

Not so daft as it may sound.

 

When I sailed dinghys there was a fad for having a matt finish on the hull of your boat (Go fast white). The theory was that water clinged to the hull in the tiny crevices of the matt paint. This produced a layer of water attached to the hull which caused less friction as the boat travelled through the water. The converse was that if you had a highly polished hull the air would cling in globules, the reverse of water on a highly polished car and slow the boat down.

 

Never really knew if this was true or just a marketing gimmick.

[Keeping Up]

If it's raining hard enough the rain suppresses your wash so you can go faster without it breaking against the banks (or at least it appears to).

[bizzard]

Not so daft as it may sound.

 

When I sailed dinghys there was a fad for having a matt finish on the hull of your boat (Go fast white). The theory was that water clinged to the hull in the tiny crevices of the matt paint. This produced a layer of water attached to the hull which caused less friction as the boat travelled through the water. The converse was that if you had a highly polished hull the air would cling in globules, the reverse of water on a highly polished car and slow the boat down.

 

Never really knew if this was true or just a marketing gimmick.

Lots of quirky trends with racing sailing dinghies,sails and masts were a favorite.Everyone would usually clamour for the latest aluminium,stiffest most aerodynamic,and most expensive mast,with all the latest tackle on it,until someone won a major race with the same class of boat with an old half rotten Spruce mast and then most would start hunting around for a wooden one thinking it would make them win races too.

The old old story really,a good workman never blames his tools.

[Guest]

Not so daft as it may sound.

 

When I sailed dinghys there was a fad for having a matt finish on the hull of your boat (Go fast white). The theory was that water clinged to the hull in the tiny crevices of the matt paint. This produced a layer of water attached to the hull which caused less friction as the boat travelled through the water. The converse was that if you had a highly polished hull the air would cling in globules, the reverse of water on a highly polished car and slow the boat down.

 

Never really knew if this was true or just a marketing gimmick.

Bloody hell hadn't heard that in years. I think it is called the laminar effect? Tuners use the same principle when gas flowing cylinder heads I am reliably informed. Too smooth a finish on the ports is said to reduce gas flow and not improve it.

[Ray T]

Bloody hell hadn't heard that in years. I think it is called the laminar effect? Tuners use the same principle when gas flowing cylinder heads I am reliably informed. Too smooth a finish on the ports is said to reduce gas flow and not improve it.

 

http://en.wikipedia.org/wiki/Laminar_flow

[Guest]

http://en.wikipedia.org/wiki/Laminar_flow

Cheers I'll have a gander at that. Hadn't heard of laminar flow in donkeys years.

[JerryP]

We have noticed that passing boats go past much more quickly when it's raining. So could it be that rainwater acts as a lubricant speeding their passage ?http://www.canalworld.net/forums/public/style_emoticons/default/closedeyes.gif

 

TC

 

 

of course rain acts as a lubricant ,just think what happens when you drive a car and put the brakes on hard in the wet

[Top cat]

Not so daft as it may sound.

 

When I sailed dinghys there was a fad for having a matt finish on the hull of your boat (Go fast white). The theory was that water clinged to the hull in the tiny crevices of the matt paint. This produced a layer of water attached to the hull which caused less friction as the boat travelled through the water. The converse was that if you had a highly polished hull the air would cling in globules, the reverse of water on a highly polished car and slow the boat down.

 

Never really knew if this was true or just a marketing gimmick.

 

I seem to recall from my model yatch racing days that a matt finish was said to reduce drag. It certainly works on model aeroplane wing where at the low reynolds numbers they fly at a turbulent flow stays attached to the wing better than a laminar flow. We even used to fit strips of elastic in front of the leading edge on free flight competition models.

 

So applying this to my narrow boat all that debris stuck on the bow is there to promote turbulent flow and make it go faster. Which is something our water skier appreciates.

 

TC

Edited April 12, 2012 by Top cat

[Donald Gilchrist]

Not so daft as it may sound.

 

When I sailed dinghys there was a fad for having a matt finish on the hull of your boat (Go fast white). The theory was that water clinged to the hull in the tiny crevices of the matt paint. This produced a layer of water attached to the hull which caused less friction as the boat travelled through the water. The converse was that if you had a highly polished hull the air would cling in globules, the reverse of water on a highly polished car and slow the boat down.

 

Never really knew if this was true or just a marketing gimmick.

Thought this came from the shark skin idea,its quite ruff and makes them go faster. Dont know the sience behind it.

[JDR]

I know that on a motorbike with carbs riding in the rain on a long run regularly gives a 5-10mpg boost in fuel economy.

 

I don't think it's due to low barometric pressure, I've ridden bikes above 10000ft and as the pressure drops with altitude carb'd bikes can really struggle as the engine runs rich.

 

Partly it may be due to riding smoothly with minimal use of brakes but I think the main reason is reduced friction between tyres and road.

Edited April 12, 2012 by JDR

[Manxcat]

JDR said "I know that on a motorbike with carbs riding in the rain on a long run regularly gives a 5-10mpg boost in fuel economy."

 

True, I used to find my CB125S went much better in the wet, back in my spotty youth.

My current winter hack, a K75, does it to a lesser extent.

As post #2, this is because the water vapour in the ingested air causes greater fuel burn efficiency.

Wikki link

It was used in tuning racing engines for a while but lugging a tank of water around to inject into the inlet soon gets you into diminishing returns.

I think that you are right that smoother ridding in the wet also helps.

 

The rolling resistance of the tyre wet/dry is more due to the construction of the tyre and the rubber compound.

Edited April 13, 2012 by Manxcat

[twbm]

Is it not associated with the reduced liklihood of someone opening their hatch to chant the mantra irrespective of whether or not you've actually disturbed their boat?

[Morat]

Is it not associated with the reduced liklihood of someone opening their hatch to chant the mantra irrespective of whether or not you've actually disturbed their boat?

 

That one gets my vote

 

People are more likely to moan if there's no downside.

[rrt2]

Is it not associated with the reduced liklihood of someone opening their hatch to chant the mantra irrespective of whether or not you've actually disturbed their boat?

 

 

superb

[Top cat]

Is it not associated with the reduced liklihood of someone opening their hatch to chant the mantra irrespective of whether or not you've actually disturbed their boat?

Sounds like the best theory so far

 

TC