Yachting myth busters

[pagoda]

You need to have a certificate or be qualified or have the right training by some organisation to enable you to try something.
Rubbish have a go .... allow yourself to get it wrong and if you do have another go.
Modern teaching methods seem to teach our children you cant or you need permission rather than giving them a you can do anything attitude. Sailing is becoming the same, there is always some self appointed organisation or other who wants to give a certificate for something or save you for that matter.
Can't even wind surf on Hayling beach now without some idiot wanting to give you permission to do so.
Can't swim on a beach now unless the teenagers with 'lifeguard' written on their T-Shirt have said it is safe to do so, I have been commanded out of the water on Wittering beach by a jumped up teenage girl before (of course I ignored the stupid kid) she stomped off muttering about the bad example I was setting ignorant of the bad example she was setting.

I can relate to that nonsense..
I've been out on Scottish hills, sometimes on paths sometimes not. No big deal. A whole generation (or two) are learning NOT to go anywhere which is not approved or signposted or similar. They look aghast if I simply take off over broken open ground on a simple A>B mission. One reason I like sailing. With a bit of common sense and understanding of COLREGS you can almost go where you like!
Lots of freedom is being educated out of our childrens' life styles.....

Apologies for the Loungish thread drift !

 

[Daydream believer]

Can't swim on a beach now unless the teenagers with 'lifeguard' written on their T-Shirt have said it is safe to do so, I have been commanded out of the water on Wittering beach by a jumped up teenage girl before (of course I ignored the stupid kid) she stomped off muttering about the bad example I was setting ignorant of the bad example she was setting.

One year , in Belgium, I called emergency services when 2 pairs of kids, at the same time, in unrelated incidents got into trouble. One drowned & i watched him drown, saw his mother screaming & i was unable to do a thing about it. they took him off the beach in a helicopter & the other 3 in ambulances
The kids had strayed out of the regular swimming area & had ignored the warning flags
Personally I would rather the lifeguards are there -A child might have lived if they had been, & if you ignore them or make their job harder it just makes you a .....well others can decide. Just because someone is younger than you does not make you cleverer.

 

[AntarcticPilot]

I can relate to that nonsense..
I've been out on Scottish hills, sometimes on paths sometimes not. No big deal. A whole generation (or two) are learning NOT to go anywhere which is not approved or signposted or similar. They look aghast if I simply take off over broken open ground on a simple A>B mission. One reason I like sailing. With a bit of common sense and understanding of COLREGS you can almost go where you like!
Lots of freedom is being educated out of our childrens' life styles.....

Apologies for the Loungish thread drift !

For goodness' sake! How would I have done my undergraduate geology field-work if I'd been constrained by footpaths and signposts? It's not hard to use a compass and an OS map to navigate accurately across hill country, providing you've got the basic good sense to watch out for the visibility changing. Much easier to navigate under those conditions than at sea without GPS, and we could all manage that, couldn't we!

 

[ghostlymoron]

Just thought of another one.
Stopping the prop produces less drag than letting it freewheel.

 

[Seajet]

I think the jury is still out on that one, as a freewheeling prop must require energy to turn, and presents basically a full disc to the water, drag wise ?

Anyway the important thing is, freewheeling props wear out shafts and bearings etc...

 

[prv]

I think the jury is still out on that one, as a freewheeling prop must require energy to turn

More or less energy than it takes to stir up the water behind a locked prop?

(Moot point to me, as we have a folder.)

Pete

 

[sailorman]

Sailing a large charter yacht in the Solent is easy

 

[ghostlymoron]

I saw a video of a YW test recently that proved that freewheeling is much less drag. Locked prop is very nearly equal to towing an 8" bucket. Some gearboxes prohibit locking and some prohibit freewheeling buts that's another matter.

I think the jury is still out on that one, as a freewheeling prop must require energy to turn, and presents basically a full disc to the water, drag wise ?

Anyway the important thing is, freewheeling props wear out shafts and bearings etc...

 

[sailorman]

I saw a video of a YW test recently that proved that freewheeling is much less drag. Locked prop is very nearly equal to towing an 8" bucket. Some gearboxes prohibit locking and some prohibit freewheeling buts that's another matter.

I doubt those findings & why would a sailor use a 3 bladed prop in the first place

 

[Seajet]

I agree with Sailorman, a sailor isn't going to be using a fixed 3 blade prop unless there's a pressing reason - can't afford a change, has to use the boat as a tug ?!

Let's see the figures for a fixed 2 blade behind a skeg, or a feathering 3 blade prop ? The latter seem to make a living charging quite a lot, so people must think there's a good reason to have them.

No-one has countered the idea that a freewheeling prop wears the shaft, bearings etc yet; I'm saying it does !

 

[Daydream believer]

I doubt those findings & why would a sailor use a 3 bladed prop in the first place

Smoother running than a 2 blade ie less vibration
Do not forget that one can get a feathering or folding 3 blade prop so it does not have to be fixed

 

[Seajet]

I think the example was a fixed 3 blader.

No self respecting sailor is going to carry that around, unless in unusual circumstances where every bit of progress has to be wrung out of the engine, at the expense of sailing performance.

I'm happy, I have a 3 blader when motoring, and zero blades and a flat smooth hull when sailing !

 

[Daydream believer]

I think the example was a fixed 3 blader.

No self respecting sailor is going to carry that around, unless in unusual circumstances where every bit of progress has to be wrung out of the engine, at the expense of sailing performance.

I'm happy, I have a 3 blader when motoring, and zero blades and a flat smooth hull when sailing !

But a lot of lifting which can be really difficult in a big sea

 

[Kelpie]

For avoidance of doubt, someone has gone to the trouble of solving the free vs locked prop debate:

http://www.catamaransite.com/propeller_drag_test.html

tl;dr- a locked prop generates almost three time the drag of a spinning one.

 

[Seajet]

But a lot of lifting which can be really difficult in a big sea

I haven't found that in the tens of thousands of miles I've done in my A22, but I'll bow to your obviously superior experience at it.

 

[prv]

For avoidance of doubt, someone has gone to the trouble of solving the free vs locked prop debate:

You're very naive if you think mere proof will solve that debate

Pete

 

[Seajet]

For avoidance of doubt, someone has gone to the trouble of solving the free vs locked prop debate:

http://www.catamaransite.com/propeller_drag_test.html

tl;dr- a locked prop generates almost three time the drag of a spinning one.

7) Freewheeling is little bit of a misnomer. The shaft was not actually allowed to freewheel with minimal to no friction. The friction bearings I designed were tightened and adjusted to closely mimic the friction of my own sailboats shaft. This test was primarily for me and my own curiosity and then secondarily for the sailing community. This is why the depth of the prop in the water matches my CS-36T and the shaft friction was set to begin spinning at about .8 - 1.2 knots which is what it does on my own boat.

Just one of many reasons why I'm not convinced by a bloke in his garage...

 

[prv]

Just one of many reasons why I'm not convinced by a bloke in his garage...

Because he set it up to match his (presumably fairly typical) yacht? What should he have done instead? Made it not like a yacht?

What about the MIT or University of Strathclyde studies, what don't you like about those ones?

Pete

 

[Seajet]

What I don't like is the chap setting up an uncalibrated friction device, with no control example to relate to.

I haven't seen the Uni examples you mention, but perhaps my soul is scored by the recently retired Uni' Professor coming to look at the corrosion on my first keel was that " The quarter of an inch deep holes in the 3/4" mild steel plate were caused by the speed of the boat through the water ".

Now I know you like to make fun about my genuine mentions of the Anderson's performance, but I'd never thought she went fast enough to wear away significant bits of mild steel !

I made a mental note to avoid any ' marine engineer ' trained by this character...

Since then, Pete, my opinion of Uni's and Professors has been somewhat jaundiced.

 

[prv]

What I don't like is the chap setting up an uncalibrated friction device, with no control example to relate to.

Ah, as opposed to the carefully calibrated test rig that you refer to when you assert the opposite conclusion?

Pete