Jeff, I have had other matters to take care of the past several days
(including cooking Thanksgiving dinner for family and guests, and also
taking the boat out), and I have been somewhat derelict in not
responding to some comments in your more recent notes. -

Jeff wrote:


I actually did engineering, what did you do? Write product liability
waivers? You have trouble taking the high road here, Jim, after you
explained to us that all of the warnings that come with a Mac is just
lawyer talk that can be ignored. Unless, of course, it can be used to
save the company when children die as the boat rolls over in calm
weather. It really amazes me how you can shift positions to suit your
need. Is that what you learn in lawyer school?

Sure thing Jeff. - Of course, it's clear that you cherry-picked and
substantially misrepresented what I said. I never said that the
warnings that come with a Mac can be ignored, and you know it. In fact,
in the very discussion from which you quote, I made that point quite
clear. What I said was that, IMHO, attorneys were involved in the
wording and display of the warning, and that in later sections of the
owners' manual instructions are given for motoring WITHOUT the water
ballast! (Incidentally, Jeff, do you actually think that attorneys were
NOT involved in this matter?) As far as my own interpretation and
practice, I have never sailed or motored my Mac 26M without the ballast,
though I would not be adverse to motoring WOB in relatively calm
conditions. I note that many other Mac owners routinely motor the boat
without the ballast. Also, remember that the 26M includes substantial
permenant ballast that remains without the water ballast.

Once more, Jeff, where did I say that those warnings could be ignored?
Or were you confusing your own particular interpretation of supposed
implications with what I actually said? Also, why would you stoop to
cherry-pick that one statement, when you know full well that my further
statements during that particular discussion made it quite clear that I
certainly did not think the warnings should be ignored?


It starts at the bow, and it ends at the stern. The diagram clearly
shows the water ballast running the entire length of the boat. If
anything, it looks that the tanks is deepest in the forward area.
The cross-section at the forward station under the hatch appears to
be by far the largest, indicting that a large portion of the water
ballast is forward.

Here's the diagram again:
http://www.macgregor26.com/drawings/drawings.htm
please tell us if there's any other way to interpret this?


Yes, there is another way to interpret it. - The correct way. The Mac
26M has a a drainage opening and large gate valve positioned on the
lower portion of its transom, the purpose of which is to permit the
ballast water to drain out of the tank when desired. The narrow,
elongated, cross-hatched "bulges" shown at the bottom of the hull in
cross-sections 4 and 5 are actually channels that conduct ballast
water from the ballast tank to the drainage opening when the bow is
elevated. When the gate valve on the stern is opened with the boat
sitting on a launch ramp, for example, water from the ballast tank is
permitted to drain out through the drainage valve, a process that
takes about 4 minutes. - In other words, the cross-hatched portions
you interpreted as being part of the ballast tank are actually
conduits that communicate with the ballast tank for permitting the
ballast water to drain out, but they are not part of the tank itself.
And, because of their small volume, they have little effect on the
distribution of mass along the longitudinal axis of the boat.


OK, you made your point, there's not much ballast aft of the mast. Of
course, my point has really been that there's a lot forward of the mast,
so you just helped prove my point.

I think it's pretty clear by now that you lost on that point, Jeff. The
sections you thought were extensions of the ballast tank were drainage
tubes for permitting the tank to drain out the valve on the stern when
parked on the launch ramp.

More significantly, your original theory was that, because the ballast
extended "the entire length of the boat," you thought it would
contribute to pitching of the boat. As should now be understood, the
volume and mass of the ballast is in an area slightly forward of
amidships, rather near the mast. Moreover, the ballast tank is tapered
at its forward and rear end portions, further reducing the mass of
ballast spaced furthest from the central or largest portion, thereby
lessening the moment of inertia of the ballast when the boat pitches
upon a wave, etc. As to the fact that the ballast tank extends forward
to the bow, two factors apply. First, the distance from the longitudinal
center (largest or widest portion) of the ballast tank to the bow is
substantially shorter then that to the stern, so it's appropriate that
the ballast tank extend to the bow (remembering also that the forward
portion or the tank is tapered, thereby reducing pitching inertia).
Secondly, for balancing the boat in the water to compensate for the
weight of crew and motor at the stern, it would again be appropriate to
position the longitudinal center of mass of the ballast tank somewhat
forward along the length of the hull.


And by the way, what happened to your claim that the entire boat was
protected by a "doubled hull" - now you're claiming it's just a small
portion. Was that just "lawyer talk" that we can ignore?

And with a 250 pound engine hanging of the stern, that's a lot of
mass in the extremities.


Nope. The boat is designed to be balanced fore and aft with an
outboard and several persons in the cockpit.


Jeff, you again misquote what I said to make your point. - I never said
that the "entire boat" was protected by a doubled hull. Only that
adjacent the ballast tank. - Do you have any ethics at all?

You also again cherry picked the statement you relied on, since in later
portions of that discussion some months ago I made it quite clear that
the boat didn't have a doubled hull protecting the entire boat. - But
you knew that when you decided to misrepresent and cherry pick my
statement, didn't you Jeff? You shamelessly misquote and cherry-pick
when you think you can get by with it. - Do you have no self-respect
whatsoever, Jeff?


In other words, you are totally ignorant of the concept of "moment of
inertia." Perhaps you should take some time off now and review basic
physics. This is the central issue of the discussion, and now you're
confessing that you have no idea what its about. Good one, Jim.

...

Additionally, the heavier, permanent ballast is positioned
amidships, below the mast.



Just where ballast should be. Good for them.


As noted above, the boat is designed to be balanced with an outboard
and with several persons in the cockpit. And it is.


Yes, the large mass in the stern (the engine) is nicely balanced by the
large mass of the water ballast in the bow. Now explain to us the
meaning and significance of "moment of inertia."


Moment of inertia in this context relates to rotational inertia, that
is, the tendency of the boat during pitching movement to keep rotating,
or pitching, in the same rotational direction. The moment of intertia of
a body with respect to any axis is the sum of the products obtained by
multiplying each elementary mass by the square of its distance from the
axis. Since it's proportional to the square of the distance from the
axis of pitching rotation, MacGregor's design (positioning most of the
mass near amidships rather than evenly distributed along the entire
length of the boat) was proper.

Incidentally, Jeff, there are other forms of inertia (e.g., resistance
to upward and downward movement, resistance to deceleration of the boat
during forward movement) that are in some respects disadvantages to
small, light boats such as the Mac. As I have consistently stated, the
Mac has good and bad features, and one of the disadvantages to any light
boat is that it doesn't sail as steadily, with as much forward momentum,
as does a large, heavy vessel. (You would have done better to ignore the
ballast issue altogether and concentrated instead on some of the
obvious disadvantages of small, light boats.)


Jeff, I've sailed many boats. The Mac 26M doesn't pitch excessively
and doesn't pitch more than most others. (Have you sailed the 26M? -
No?)


I'd love to, but most of the Mac owners hardly ever go out.

Really? And do you have any evidence to back up that bit of propaganda?
In any event, I was out sailing my Mac yesterday. - When was the last
time you took your boat out Jeff?



I have
sailed by them a number of times and they do seem to bob around more
than heavier boats.

Actually, it's probably true that the Macs, weighing only around 4,000
pounds with ballast and crew, "bob" around more than a 20,000 lb vessel.
Then again, its also true that a Ferrari or Porsche weighs less than and
has a stiffer ride than a Lincoln Town Car. It sort of relates to
personal taste, and what you're going to do with the vehicle or vessel.
For example, I motored back to the marina at around 13 knots, despite
rather choppy water conditions, which gave me more time out on the Bay
for sailing.



And, when did you last have your eyes examined, Jeff?


Funny thing, as I've grown older my vision has improved. Now I spend
most of the time without wearing the glasses I've worn since I was ten.
I guess that means I've just gotten smarter.


Interesting. I also stopped wearing glasses several years ago. - Does
that mean I'm getting smarter too?

Jim