Overboard!

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Roger Long

Roger Long

.
Nov 22, 2008
3,562
Endeavour 32 Portland, Maine
Barring something completely unexpected, Strider will go back in the water tomorrow afternoon. After a marathon day of bottom painting and other work, following a few other marathon days, she's ready except for painting under the keel blocks when they lift her up and squaring away the mess left in the cabin.



The finished strut. Apologies to Shoaldrafter who will always know that it is multi-colored under the bottom paint:



I also found time to make a new and lighter seat for the dinghy. The original was oak which was lightly varnished. It was so warped and cracked that it was easier to make new one out of a new pine board than to refinish. The center support is to make up for the less stiff softwood.



Plans are to depart the next day on a cruise with my son, either overnight or for a few days depending on what he works out tonight. I expect to then stick pretty close to Portland for August taking friends and sons daysailing. I'm going to save my Downeast cruise for September, the absolute best time to cruise in Maine.
 
All U Get

All U Get

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Oct 2, 2008
3,807
Pearson/ 530 Strafford, NH
Nice work Roger, we'll be looking for you on the water.
All U Get
 
sailormanbigd

sailormanbigd

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Jul 24, 2006
628
Legnos, Starwind, Regal Mystic 30 cutter, 22 trailer sailor, bow rider NEW PORT RICHEY, FL
good stuff Roger. Sounds like you have a plan, but still flexable. Thats the way it goes. Enjoy your beauty, and time with the kids.
 
Shoaldrafter

Shoaldrafter

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Dec 8, 2006
1,085
Oday 26 Starr, SC
Tender Feet

So tell us is the dink, Tender Feet,
your design?

And as you gloat over the painted strut,
did you compute the loss in speed to ruff
fairing of patch work? Did you find it to
negligible.

I saw pictures elsewhere on the restoration
of another old boat, which was a great
restoration, except that in sun light the
bottom paint highlighted the lack of fairing
smooth the hull below the water line.

I have been fortunate to watch some
guys fair a boat used for racing. Their
finished bottom was smooooth. Since then I
look back to use that work as a standard
of the way a hull is supposed to be.

They used 18 inch long air drive
sander/polishers to smooth the surface.
I will leave the computations of the differences
in surface to you experts. But smoothness
is visible.

No, you are not too old to race that boat...

Ed K

"Sailboat racing, everybody tries to make it so
complicated. But all it is is going the right
direction," Zack Railey
 
Roger Long

Roger Long

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Nov 22, 2008
3,562
Endeavour 32 Portland, Maine
Shoaldrafter said:
So tell us is the dink, Tender Feet,
your design?
Click to expand
No, it's a Puffin, built here in Maine.

did you compute the loss in speed to ruff
fairing of patch work? Did you find it to
negligible.
Click to expand
No but, as a naval architect, I know something about boundary layers. Even on a hull as clean and polished as a 12 meter, you could nail a 2 x 4 to the stern and it would never feel it. I only lost half a knot with this:



I find it hard to get too worked up over stuff that you can't see.
 
sea_casper

sea_casper

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Jun 28, 2005
440
Hunter H33 2004 Mumford Cove,CT & Block Island
Shoaldrafter said:
I have been fortunate to watch some
guys fair a boat used for racing. Their
finished bottom was smooooth. Since then I
look back to use that work as a standard
of the way a hull is supposed to be
Click to expand
I am not a marine architect, or one skilled in hydrodynamics, but I have been told, smooth is not the fastest.

The least resistance of a body moving thru a fluid, is when a boundary layer of the fluid clings to the body, we only have to look to nature for examples of this, e.g. the shark, who's skin is definitely not smooth, or even at dimpled verses smooth golf balls.
 
Maine Sail

Maine Sail

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Feb 6, 1998
11,674
Canadian Sailcraft 36T Casco Bay, ME
Roger,

Technically the small nut goes on first then the big one.... To install a prop in compliance with ABYC P-6 and SAE J755 the thin nut goes on first..;) I know many people, including many boat yards, install them incorrectly, and most props are fine, but while she's out you may want to flip them...
 
FastOlson

FastOlson

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Apr 8, 2010
1,955
Ericson Yachts Olson 34 28400 Portland OR
Get those nuts in order....

Maine Sail said:
Roger,

Technically the small nut goes on first then the big one.... To install a prop in compliance with ABYC P-6 and SAE J755 the thin nut goes on first..;) I know many people, including many boat yards, install them incorrectly, and most props are fine, but while she's out you may want to flip them...
Click to expand
Ahh Yup!
 
Roger Long

Roger Long

.
Nov 22, 2008
3,562
Endeavour 32 Portland, Maine
Maine Sail said:
Technically the small nut goes on first then the big one...
Click to expand
"Technically", and unquestionably proper for pressure vessels from which the standard was borrowed. I can't see any similarity in the dynamics of the forces involved myself. Considering how hard most props come off, there is no live load approaching yield on the prop nuts as on pressure vessel. There is also no cycling of loads. I'd rather produce the big torque to bring the prop home with the greater thread surface area of the big nut and then use the small one to lock it.

I understand pretty well the microscopic things that are happening within the threads of boilers and such. None of that seems to apply to a prop.

I suppose though that, if my prop should ever come off, this post would relieve the insurance company from paying for it:)
 
Maine Sail

Maine Sail

.
Feb 6, 1998
11,674
Canadian Sailcraft 36T Casco Bay, ME
Roger Long said:
I'd rather produce the big torque to bring the prop home with the greater thread surface area of the big nut and then use the small one to lock it.
Click to expand
I do exactly that, tighten the prop over the taper with the big nut. I then however remove the big nut and install the small one to relieve it with the big nut.

Did a seminar with Steve D'Antonio where he pointed out cases of props falling off with incorrect nut procedure. I agree that it is doubtful anything would go wrong but it takes two seconds to do it the preferred way..
 
Roger Long

Roger Long

.
Nov 22, 2008
3,562
Endeavour 32 Portland, Maine
Maine Sail said:
he pointed out cases of props falling off with incorrect nut procedure.
Click to expand
I would really like to know the failure mode. In a pressure vessel, you need quite a bit of torque to take up on the gasket. You then add a lot of load (the pressure).

With a prop, you take up on the nut and then add pressure in the opposite direction, except when the vessel is in reverse. Full power is seldom used in that direction.

If the nut sequence has any thing to do with loads added after initial torquing, it seems like the nuts should be reversed from SAE / ABYC standards.

If the props came off, how does Steve know the nuts were "backwards"?
 
Maine Sail

Maine Sail

.
Feb 6, 1998
11,674
Canadian Sailcraft 36T Casco Bay, ME
Roger Long said:
I would really like to know the failure mode. In a pressure vessel, you need quite a bit of torque to take up on the gasket. You then add a lot of load (the pressure).

With a prop, you take up on the nut and then add pressure in the opposite direction, except when the vessel is in reverse. Full power is seldom used in that direction.

If the nut sequence has any thing to do with loads added after initial torquing, it seems like the nuts should be reversed from SAE / ABYC standards.

If the props came off, how does Steve know the nuts were "backwards"?
Click to expand
Most remained on due to cotter pin but they sheared the key due to coming loose. When I say lost I did not mean lost as in gone but lost as in propulsion. My gut was that this was likely two things, lack of proper lap fitting the prop & shaft and improper nut installation.

There was a good article in Professional Boatbuilder a few years back on this and I will try and dig it up..
 
jibes138

jibes138

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Jan 27, 2008
3,045
ODay 35 Beaufort, NC
Interesting discussion, what is lacking is why? What purpose would be served by putting the thin nut on first? I don't get it. If the prop will fail by shearing the key what good is the cotter pin? It doesn't prevent the nuts from loosening their torque since it isn't a castellated nut. Why don't the standards use airplane methods and lockwire the nut so it doesn't come loose. I can't really recall seeing a jam nut like this used in aerospace. I can tell you putting the lockwire holes in the nuts is a big PITA.
 
Roger Long

Roger Long

.
Nov 22, 2008
3,562
Endeavour 32 Portland, Maine
jibes138 said:
what good is the cotter pin?
Click to expand
As MaineSail explains just above, it keeps the prop and nuts on the shaft so you don't have to buy new ones when you have the boat hauled to figure out what all the funny noises and vibration are after the nuts back off and the prop comes loose.
 
Shoaldrafter

Shoaldrafter

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Dec 8, 2006
1,085
Oday 26 Starr, SC
Strangeness and humor of thread

Maine Sail said:
Most remained on due to cotter pin but they sheared the key due to coming loose. When I say lost I did not mean lost as in gone but lost as in propulsion. My gut was that this was likely two things, lack of proper lap fitting the prop & shaft and improper nut installation.

There was a good article in Professional Boatbuilder a few years back on this and I will try and dig it up..
Click to expand
- - - -- - - // - - -- - --

You would have thought that a forum moderator would have noticed the strangeness and humor of arguing over having one big nut and thin nut? And then getting into a musicale technical discussion thereof?

In case you have not noticed, Roger has his opinions and no facts or other opinions will be accepted.

That is o.k., it is his stump to stand on...

Ed K




 

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