On Sun, 24 Oct 2004 11:20:44 GMT, Morgan Ohlson
wrote:

On Sun, 24 Oct 2004 07:13:04 +0700, Egis/CORE wrote:

On Sat, 23 Oct 2004 16:58:02 GMT, Morgan Ohlson
wrote:

On 23 Oct 2004 16:01:42 GMT, Stephen Baker wrote:

you know little.

I don't like people to give faulty advice anyhow. I just liked to give a
hint to PeterM.A about that.

..but I will not fall to your standards of attacking...

...explained this way...

If you have a rig in solid concrete, which would matter the most to the rig?
A) wind speed?
B) the momentum of the solid concrete?

take care... hope you understand something new now!



Morgan O.

You are absolutely right. If the rig were mounted in concrete the
important force would result from wind velocity and sail area.

However -- we are discussing a rig installed on a BOAT and the
important force is righting moment.

i.e., in the case you are discussing the mast is fixed and therefore
the effective area of the sail is constant. In the case of a spar
mounted on a movable base, i.e., a boat, the spar moves and therefore
the effective area of the sail changes with changes in wind velocity,
thus the important figure is the force opposing the spar movement, the
righting moment.

Most people who have any knowledge of boats understand this fact
instinctively.

1'st... I undertand exactly what you are saying...

But tech /nature doesn't stop there. There is more to it. Especially that
part comes into account in this case, a 2 hull vessell.

You are stuck in what sometimes goes under the label "psychic prisons".


Morgan O.


Sorry old buddy but whether the boat has one hull or many the
calculation is the same since the force is the same - the force
necessary to heel the vessel, or to phrase it another way, the force
the vessel exerts in attempting to stay upright. the Righting Moment,
in other words.

Certainly the force necessary to heel a multi-hull is higher then that
necessary to heel a mono-hull but that doesn't change the fact that
the force applied to the mast is exactly the same in each case -- the
force necessary to heel the vessel against the opposing force of the
vessel trying to remain upright -- the Righting Moment.

To stay in the real world, if you approach a mast manufacturer with
the intent of designing a mast you will be asked for the righting
moment, usually RM30, i.e., Righting Moment at 30 degrees. If you
approach a marine engineer/boat designer for information regarding the
strength of a mast you will be asked for the RM30.

In short, no matter what you think, the rest of the world firmly
believes that the strength of a mast is directly dependent on the
forces opposing it, i.e., the force the vessel can exert against the
mast, the righting moment in other words.

Now it appears that either (1) you are wrong; or, (2) the rest of the
world is wrong. Take your pick.





Cheers,

Bruce
(k4556atinetdotcodotth)