Yup.... and no way it would hold the boom so I could hoist the auxiliary out
of the engine room with one!

For that you need a topping lift..

CM

"DSK" wrote in message
| Have either of you all ever actually seen a solid vang?
|
| DSK
|

Capt. Mooron wrote:
Yup.... and no way it would hold the boom so I could hoist the auxiliary out
of the engine room with one!

For that you need a topping lift..

In that case, the solid vangs you've seen (and/or the booms) were sadly
lacking.

If it won't hold up a piddly little outboard motor, how is it going to
hold the force of the whole boat driving the boom tip into wave crests,
or any of the other things that can be expected to happen when you
*really* sail, occasionally in hard conditions?

I think you're forming your opinion based on incomplete data.

A *real* solid vang (and boom) will fulfill all the functions of a
topping lift, except as an emergency backstay replacement. I've seen a
lot that wouldn't, but I don't like them either.

It's sort of like a centerboard one-design that won't plane... what's
the point?

Fresh Breezes- Doug King

In article ,
DSK wrote:
A *real* solid vang (and boom) will fulfill all the functions of a
topping lift, except as an emergency backstay replacement. I've seen a
lot that wouldn't, but I don't like them either.

It's sort of like a centerboard one-design that won't plane... what's
the point?

Doug, I thougth that's what you were saying it would do... as an
emergency backstay. Oh well... my reading comprehension is going
downhill fast.



--
Jonathan Ganz (j gan z @ $ail no w.c=o=m)
http://www.sailnow.com
"If there's no wind, row."

Jonathan Ganz wrote:
Doug, I thougth that's what you were saying it would do... as an
emergency backstay. Oh well... my reading comprehension is going
downhill fast.

My bad. I have been in a hurry all week and am probably not writing very
clearly.

DSK

Since you're clearly not perfect, I'm going to change my
vote for president... to Willie Nelson.

In article ,
DSK wrote:
Jonathan Ganz wrote:
Doug, I thougth that's what you were saying it would do... as an
emergency backstay. Oh well... my reading comprehension is going
downhill fast.

My bad. I have been in a hurry all week and am probably not writing very
clearly.

--
Jonathan Ganz (j gan z @ $ail no w.c=o=m)
http://www.sailnow.com
"If there's no wind, row."

"DSK" wrote in message

| If it won't hold up a piddly little outboard motor, how is it going to
| hold the force of the whole boat driving the boom tip into wave crests,
| or any of the other things that can be expected to happen when you
| *really* sail, occasionally in hard conditions?

it's an auxiliary diesel.. 30 HP! The vang holds the boom down not up...
yes it has the capacity to hold up a boom up with some weight.... but that
is not it's primary function.

Leverage is required at the end of the boom for lifting. I'm certain you are
familiar with fulcrums?
Where would you fasten the mainsheet to the boom... generally it's 50% of
the length or more. Look where the vang is... at what 15%?

|
| I think you're forming your opinion based on incomplete data.

My data seems more complete than yours at the moment Doug.


|
| A *real* solid vang (and boom) will fulfill all the functions of a
| topping lift, except as an emergency backstay replacement. I've seen a
| lot that wouldn't, but I don't like them either.

No Way Doug!! No for all the tea in China. The engineering is out to lunch
for such a claim.

CM

Capt. Mooron wrote:
it's an auxiliary diesel.. 30 HP!

???
What is?

.... The vang holds the boom down not up...

Therein lies your error. A solid vang holds the boom up and down.


yes it has the capacity to hold up a boom up with some weight.... but that
is not it's primary function.

Why isn't it? That's like saying that because a bridge is designed for
cars to drive over it, it won't hold up a person walking across.



Leverage is required at the end of the boom for lifting. I'm certain you are
familiar with fulcrums?

Yes. I fail to see your point though. If the vang holds the boom up,
then it holds the boom up.

If the vang will hold the boom down under heavy sailing loads, then it
will probably hold at least as much in the opposite direction, nyet?

How much leach tension do you think your boat generates in a good breeze?


Where would you fasten the mainsheet to the boom... generally it's 50% of
the length or more. Look where the vang is... at what 15%?

Depends.

It's not a relevant issue though. Wherever the boom vang is attached, if
it will stand up to the load then it will... umm... stand up to the
load. If not, then it wasn't strong enough to begin with and that's true
whether it's a solid vang or not.

|
| A *real* solid vang (and boom) will fulfill all the functions of a
| topping lift, except as an emergency backstay replacement. I've seen a
| lot that wouldn't, but I don't like them either.

No Way Doug!! No for all the tea in China. The engineering is out to lunch
for such a claim.

Actually the engineering is quite sound. If you have problems with vangs
breaking and booms folding up, then that suggests that your engineering
needs a little more beef and less cheese.

Fresh Breezes- Doug King

Doug,

Your Bridge example is WRONG. Those cables hanging down are for
suspension. Not compression. I think you can remember the Tacoma Narrows
Bridge when the wind got under it. IT FALL DOWN GO KAPLUNK!

OT

"DSK" wrote in message

| Yes. I fail to see your point though. If the vang holds the boom up,
| then it holds the boom up.
|
| If the vang will hold the boom down under heavy sailing loads, then it
| will probably hold at least as much in the opposite direction, nyet?

No Doug! No No No!.... look the vang may be able to hold the stresses on a
sail "down"... but it will never hold the stresses of a weight at the end of
the boom "UP". The leverage just isn't there. This is not a hydraulic arm on
an excavator! If it were the vang would be massive ... require an engine to
power the compressor and be attached to the end of the boom.

Look..... I can understand where your assumptions are based but I'm
thinking you have not taken into consideration the engineering incorporated
into the vang and it's intended use. If you have 10,000 lbs of pressure on
the main only a fraction of that force will be utilized to incur lift on the
boom. The vang is not holding down the entire pressure placed on the main.

For using the boom as a lifting device.... you will stress the vang unduly
with a set-up located that far back on the load arm. It's not designed for
that. A topping lift to the end of the boom requires much less force to hold
the boom level on a lift than the stresses placed on a vang that is located
at 15% of the load arm length. I don't care if it's a 1/2" I Channel carbon
steel beam for a boom! We are not discussing boom failure here.... we are
discussing load bearing to the vang.

I await your rebuttal... :-)

CM

| If the vang will hold the boom down under heavy sailing loads, then it
| will probably hold at least as much in the opposite direction, nyet?

Capt. Mooron wrote:
No Doug! No No No!.... look the vang may be able to hold the stresses on a
sail "down"... but it will never hold the stresses of a weight at the end of
the boom "UP".

Why not? If the boom can take the torsion in one direction, then unless
it is a very weird asymmetric structure, then it will take the same in
the opposite direction.


... The leverage just isn't there.

Sure it is. It's exactly the same in both directions.

What I'm saying is the same as saying if you can stand on a beam (let's
say a 2x6) between two sawhorses, and it doesn't break, then you can
turn the beam over and still stand on it. You're saying that it doesn't
work that way, if the beam doesn't break one way then it will definitely
break the other...

.... This is not a hydraulic arm on
an excavator! If it were the vang would be massive ... require an engine to
power the compressor and be attached to the end of the boom.

The max forces are limited by the righting moment of the boat. On a 30
footer, it doesn't need to be that massive. On bigger boats... take a
look at the vangs on IACC racers...


Look..... I can understand where your assumptions are based but I'm
thinking you have not taken into consideration the engineering incorporated
into the vang and it's intended use.

Actually, I have. It's not that complicated. Try drawing out a diagram
of moments. If you need a refresher
http://www2.umist.ac.uk/construction...xp/sfbmdex.htm


... If you have 10,000 lbs of pressure on
the main only a fraction of that force will be utilized to incur lift on the
boom. The vang is not holding down the entire pressure placed on the main.

No, it isn't... but it is holding down 100% of the leach tension, which
is very large. It also takes all the load of the mainsheet when hauled
in tight to go to windward. If it doesn't break when you honk down on an
8:1 purchase, then it should hold at least 8X your honking strength


For using the boom as a lifting device.... you will stress the vang unduly
with a set-up located that far back on the load arm.

???

... It's not designed for
that.

It should be. Anything less would not be safe for sailing IMHO.



I await your rebuttal... :-)

If I give you a re-buttal, then who was the butt in the first place?

Seriously, I'm not saying 'all solid vangs are great for lifting heavy
objects' because many aren't. But then remember Sturgeons Law '90% of
everything is crap' and then tell me why it *shouldn't* be.

Some are. I know that for a fact. And if I had a solid vang that's what
I'd insist on. YMMV

DSK