Captain/Owner Sleeping at the Helm

[Uncle Bob]

Originally Posted by NorthernMac

It's odd, in the aviation world this isn't a debate, it's a accepted fact that windmilling is more drag. Next time I'm out I'll do a little experiment, ether way don't feel like ty noise, or lack of cooling water in the dripless or spinning that much for ether little or a negative

Let you in on a secret, water is not air, water has different properties to air as do the props that operate in each. With a little searching you will find a number of tests that have been well recorded and documented. To get you started a poster by the name of Maine Sail has done one good one as has Practical sailor, and I believe a university somewhere.

[Smokeys Kitchen]

Originally Posted by Saleen411

A spinning propellor is much more drag than a feathered prop on an airplane, A spinning propellor is even more drag than a non spinning unfeathered prop on an airplane.

Evidently, a spinning propellor is LESS drag than a stationary prop on a boat. Which is just the opposite. I don't pretend to understand why, but I believe there is published information on this subject.....like from highly regarded institutions such as MIT.

I also don't know what most manufacturers recommend....I've read some say don't let the prop spin and others that say you should.

Wouldn’t a spinning prop on a boat be spinning in the opposite direction while a prop on a plane could not do that? Not a pilot - just asking

[StuM]

Originally Posted by Smokeys Kitchen

Wouldn’t a spinning prop on a boat be spinning in the opposite direction while a prop on a plane could not do that? Not a pilot - just asking

No

[Uncle Bob]

Originally Posted by jmschmidt

Maybe for sail-drives, that's why I wouldn't have a boat with one. Some boats may have poorly engineered transmissions that are damaged by placing them in reverse when under sail. These boats usually have, or should have shaft locks to reduce the increased drag due to free-wheeling.

Yeah, yeah, I saw the guy's video with the test rig he built to "prove" that a free- wheeling prop does not create more drag that a locked one. If you have a few hours I could explain it to you, has do do with the fact that his text rig was not under any load so his apparent test results were bogus.

"I can explain it to you, but I can't make you understand" – Author Unknown

Hi, please feel free to post or link to at least one, preferably more, tests that indicate your stated position on prop drag is in fact the correct one, go, PLEASE.

[Cpt Pat]

Wow. Not a lot of Crew Resource Management training in boating, huh?

The "Captain is God" mentality bent a lot of airplanes before NASA developed CRM. Your skin is on the boat too. If it's safety related: "if you see something, say something." If it's just a difference in style, fine. Keep quiet and don't mess with things that don't matter. But there may be a good reason for the difference in style: it could be your training differs from Captain God's: you had training, he/she didn't.

Just read the story about the wreck of the El Faro. The crew had up-to-date weather, the captain didn't. The crew thought he was nuts to "run the storm" -- yet the crew didn't speak up.

They all died.

In aviation, first officers have been know to legitimately lock a captain out of the cockpit when he had clearly lost his mind.

I suppose a sailboat is the last bastion of the tyrant. All you need is enough money to buy a boat and then appoint yourself king.

Unlike God, I'm not omniscient. I only have one set of eyes. I always say to my crew: "If you see something, say something. You will not be 'dinged' if that something is irrelevant or trivial." Experienced crew members have never brought up trivia, and it's a good training opportunity for inexperienced crew - that also makes them much less anxious. And they will trust you - and should trust you - more if they know you are considering their concerns. Trust matters much more than authority.

I sometimes wonder if some of the "skipper fell overboard" stories weren't motivated by a skipper who was a raging megalomaniac. The life you save may be your own, skipper...

[Adelie]

Originally Posted by Cpt Pat

....
The "Captain is God" mentality bent a lot of airplanes before NASA developed CRM. ...

NASA did not develop CRM, though they were a major part of it's development and one of their's did coin the term.

[Cpt Pat]

Originally Posted by Adelie

NASA did not develop CRM, though they were a major part of it's development and one of their's did coin the term.

Hummm. I met one of the authors of the original CRM program* (then called "cockpit resource management") at Ames Research Center, working in Human Factors research. They did a lot of jumpseat flying. Did they overstate their involvement? Of course, the entire American aviation industry "developed" it on from there. With huge resistance from many Captain Gods in aviation.

The funny thing is, I'm told, when an old fashioned airline captain complains about sharing authority, often the advice given is to go buy a sailboat.

*https://www.elsevier.com/books/crew-...-0-12-812995-1 (see bios at bottom)

[Adelie]

Did they come up with the program de novo? Or did they compile work from a lot of other parties, add some or a lot of their own and then give it a name?


http://www.nycaviation.com/2014/12/e...nagement/37271

https://www.linkedin.com/pulse/histo...iii-paulo-neto

https://code7700.com/crm.htm

PanAm was working on it internally from 1973 when the FAA told them to shape up or be grounded.

NTSB had a lot to say about cockpit culture too in the 1970s in their accident reports.

There’s even a British guy going back to the 1950s who talked about human factors.

Giving NASA all the credit for originating CRM is like giving Bill Lapworth all the credit for the switch from full to fin keela on larger keelboats. There’s a lot of history that came before both.

[Wotname]

Originally Posted by MicHughV

I've always been interested in this topic for reasons beyond my understanding...but it appears that generally speaking, the projected surface area of the prop, is always considered when talking about drag...but what about the shape of the blade ? Most all blades will generate a low pressure and high pressure side that must also somehow influence whether or not a prop generates drag whether spinning or not, and the pitch angle would certainly influence this ? Yes, no ??
I don't have an opinion on the matter, just asking the question. I know this topic has been beat to death in other threads, and I don't wish to stir the pot, just curious to know from an " expert" point of view, the question above.

As Uncle Bob alluded to upthread, air is a compressional fluid and water is an un-compressional fluid. Just one of many reasons why we can't make easy comparisons between the airplane prop and the boat prop.

Originally Posted by jmschmidt

........

Yeah, yeah, I saw the guy's video with the test rig he built to "prove" that a free- wheeling prop does not create more drag that a locked one. If you have a few hours I could explain it to you, has do do with the fact that his text rig was not under any load so his apparent test results were bogus.

"I can explain it to you, but I can't make you understand" – Author Unknown

Don't worry about knocking that guy's test rig, try understanding some basic physics and general basic science. In past threads about prop drag you have been presented with the facts backed up by science based explanations which you have ignored to debate and you continued posting contrary opinions not based in science.

If you have a basic understanding of physics or maths and if someone explains the whys and wherefores to you, it is easy to understand why a fixed blade sailboat prop has less drag when allowed to spin freely compared to locking it stationary. However you have be open to learning and understanding more than what you currently know and understand.

Everyone is entitled to his own opinion, but not his own facts.

If you would like to try again, let me know and we can revisit one of the past threads and explore the facts together rather than continuing being Off-Topic here.

[Orion Jim]

http://www.plaisance-pratique.com/IM..._sdarticle.pdf


This has been my “go to” document.

[sailorboy1]

Originally Posted by Phisher

I recently crewed on a catamaran from St. Thomas to Ft. Lauderdale.

I have only had crew once. I wonder what they thought I did wrong on MY boat. I learned a lot from the experience, mostly that I don't ever want crew again. I definitely wouldn't let one of them who couldn't follow directions and do things the way I said to back on MY boat. If I had found one on them had been going through the log looking for support of their "opinions" to use aganist me on MY boat I would have been looking for a course change to nearest land.

[MicHughV]

"crew" is one thing...
in the past, in order to raise a little cash, I sometimes "day chartered"....basically meeting tourist people in a bar that wanted to go out for a " daysail"
..once these people "pay you" they think they own both you and your boat.....throw in some alcohol..and things get interesting in a hurry...

[StuM]

Originally Posted by Orion Jim

http://www.plaisance-pratique.com/IM..._sdarticle.pdf


This has been my “go to” document.

For those with an unwillingness to consider scientific evidence or with comprehension difficulties, the take-away from that exhaustive scientific study is in the "Concluding Remarks" :
"The experimental results confirm that a locked propeller produces greater drag than does a freewheeling screw (up to 100% more drag was observed, this being at higher speeds)."


Q.E.D.

[MicHughV]

I think the above study does not take into account, the annoying whine of a spinning propellor, enough to drive a man to drink.....hmmmm....may have to re-consider my thought on that...

[BlueH2Obound]

Perhaps a moderator should split this thread into two threads:

One dealing with Captain falling asleep while on watch, which I think was the real meat of the original post.

Second one dealing with what to do with the transmission when sailing.