Re: Micro with box keel, standing room?

Hi,

I wonder what would happen to these designs if one added chine logs
as per Matt's Paradox design? From reports, it sails just fine with
the chine logs and a small lateral area...

If adding chine logs (or rails) works it also would make these boats
more stable when grounded. Combine this with, shallow draft, good
head room, no center/dagger/lee board and one would have a very
interesting combo.

Comments
Ed


--- In bolger@yahoogroups.com, "Nels" <arvent@...> wrote:
>
> --- In bolger@yahoogroups.com, "donschultz8275" <donschultz@>
wrote:
> >
> > One way to approach this idea would be to review Bolgers Small
Motor
> > Sailer, a 22' box keeled boat with lots of standing headroom.
> >
> > SMS is not a completed design but looks to be just short of
that.
> > Sorry I don't have a link handy.
> >
>
> Here is the link for Small Motorsailer:
>
> http://groups.yahoo.com/group/bolger4/files/
>
> Just be aware, that with the shallow box keel, both it and the
Alaskan
> Motorsailer are designed to have the engine running most of the
time.
>
> http://groups.yahoo.com/group/BolgerCartoons/files/Cargo%20Boat%
> 20Motorsailor/
>
> Nels
>--- Inbolger@yahoogroups.com, "Bruce Hallman" <bruce@...> wrote:
> Bolger has designed small boats exploiting a box keel for headroom
> like , 20ft _Col. HG Hassler_ , also 22ft _Small Motor Sailer_.
But
> in both cases he has added a chine for deadrise (probably to
mitigate
> the displacement mass issue).

In regard to the query about better sailing qualities for Micro with
box keel, the above point about deadrise raised by Bruce,
particularly concerning Col H G Hasler, actually woke me this
morning, so I'm guessing I think it important ;-)

In the PCB&F deadrise bottom Col H G Hasler article this paragraph
below needs to be read very carefuly; bear in mind the test hull was
the flat bottom Brick Flying Cloud:

"By spreading displacement into the ends of the boat, especially
aft, the bulky mid-body needed to float the weight can be reduced
and its waves spread out. The test hull's freedom from bogging down
in its own waves, when driven hard, was encouraging. The experience
with this craft is carried over into the Hasler's extremely unusual
displacement curve, which has almost no hollow aft, and much less
than is usual forward, a shape generally considered desirable but
unachievable."

For this sailing boat in the first sentence are they saying the
deadrise allowed by removing the bulky mid-body is necessary to
really spread out otherwise bulky mid-body caused waves, or is it
just a desirable help to the wave spreading caused anyway by the box
keel? I ask because in the following sentence the test hull does
well despite its lack of deadrise. The third sentence remarks about
the displacement curves is what was actually in my mind when I
awoke. No doubt these lines are very important for sailing
qualities. The third sentence also seems to introduce some ambiguity
into the first sentence, but is most encouraging for amateur
builders who may prefer to build the flat bottom, as I read it to
say that the test hull has the Hasler's desirable displacement curve
even though it does not have the Hasler's deadrise. Are these
displacement curves easily plotted with hull design software? If
so, does it hold up, are the curves similar enough?

Further, PCB&F do not mention "deadrise" in their article at all as
far as I can see other than that oblique bit quoted above "... the
bulky mid-body needed to float the weight can be reduced...". When
writing about Vee-bottom or multi-chine boats they sometimes mention
an advantage in a high chine forward. Perhaps the deadrise is
included to assist this, and not necessarily for spreading mid-body
waves to the ends? Col H G Hasler is a circumnavigating ocean
voyager and for an along shore cruiser, at most, like Micro with
added box keel the lack of deadrise might be a beneficial trade off
after all. Still, remarks on deadrise in the Hasler are conspicuous
by their apparent absence.

What about the Micro plus box keel designed diplacement without
deadrise?

Col H G Hasler's designed displacement 6350 lbs x 0.421875 [(3/4)^3
ie the cube of the LOA & B scale down to Micro] = 2678.90625 lbs
with **deadrise**, with box keel. Micro's designed displacement is
1650 lbs. Roughly now, with an added box keel of 18" Beam, and 9"
Depth, and 15' unflooded Length, and 0.5 PrisCoef, and 64 lbs/cu ft
seawater , flat bottom Micro would have a displacement around 2190
lbs [1650 + 540 (1.5x0.75x15x0.5x64=540)]. Its in the ball park I
think, but is ~14% on the light side a knock out? These are
different shaped hulls and this displacement difference may or may
not be terribly important, at least in some conditions. The right
amount of flooding and ballasting of the box keel should minimise
this diplacement difference if it's important. That would leave her
perhaps with the slender dead flat bottom deep pointy stern box keel
rule bending capabilities. Micro is often reported to feel like a
much bigger boat, perhaps she can go like a thirty footer!

Sorry for the long post. What do you reckon about all this stuff?

cheers
Graeme
--- Inbolger@yahoogroups.com, "Puck III" <ben_azo@...> wrote:
>
> Standing room , standing in the narrow keel is a good idea ! see :
>http://cruisenews.net/images/Puck/to have an idea :-)
> Old Ben

Nice boat Old Ben. Was she amateur or professionally built. My German
is a little better than my French, but not up to that text.

Cheers
Graeme
--- In bolger@yahoogroups.com, "donschultz8275" <donschultz@...> wrote:
>
> One way to approach this idea would be to review Bolgers Small Motor
> Sailer, a 22' box keeled boat with lots of standing headroom.
>
> SMS is not a completed design but looks to be just short of that.
> Sorry I don't have a link handy.
>

Here is the link for Small Motorsailer:

http://groups.yahoo.com/group/bolger4/files/

Just be aware, that with the shallow box keel, both it and the Alaskan
Motorsailer are designed to have the engine running most of the time.

http://groups.yahoo.com/group/BolgerCartoons/files/Cargo%20Boat%
20Motorsailor/

Nels
One way to approach this idea would be to review Bolgers Small Motor
Sailer, a 22' box keeled boat with lots of standing headroom.

SMS is not a completed design but looks to be just short of that.
Sorry I don't have a link handy.
Standing room , standing in the narrow keel is a good idea ! see :
http://cruisenews.net/images/Puck/to have an idea :-)
Old Ben

--- Inbolger@yahoogroups.com, "graeme19121984" <graeme19121984@...>
wrote:
>
> >Could such a design if done properly match or exceed the sailing
> >performance of the regular micro design under some/many/most/all
> >conditions.If perfomance was lessened, how significant would it be?
>
> If increased sailing performance means you want faster then I
> suspect PCB would simply refer you to a longer design, say Long
> Micro, as the most efficient solution. However, that not
> withstanding, I think PCB&F have proven to themselves
satisfactorily
> enough that the box keel cutwater does improve sailing qualities of
> heavy types. Speed is increased by shifting displacement to the
ends
> and lessening the hull from bogging down in its own waves. Unless
> built in materials heavier than plywood your suggestion of mostly
> flooding the keel would seem simplest. However, your suggested
> dimensions and proportions may need some adjustment as comparing,
> approximately, Micro of 15'LOA by 6'Beam to Col H G Hasler of 20'
by
> 8' we have the same relative proportions. Reducing the Col H G
> Hasler box keel proportions by the same 3/4 ratio would have it for
> Micro at 18" midships beam by 9" midships depth below the main hull
> bottom (this is not total draft). In approximately comparing Micro
> of 15'LOA by 6'Beam to Brick "Flying Cloud" of 8' by 4' we have
> ratios for LOA of ~1/2 and Beam of 2/3. Pick your choice of scaling
> ratios for the Brick "Flying Cloud" box keel beam of 15" by 7-3/16"
> depth to give Micro box keel midships dimensions of 2'6" by 14-
3/8",
> or 22.5" by 11-1/16".
>
> So from the Bolger rule bending ratios Micro box keel midships
> dimensions might be any of 18"Beam x 9"Depth, 30" x 14-3/8", or 22-
> 1/2" x 11-1/16".
>
> I'd be inclined to say the Col H G Hasler is best as main hull
> proportions are the same, and "Flying Cloud" was a test... but then
> there is that ~60 degree deadrise to consider. The real problem is
> that whichever ratio is used your proposed depth of 2' is way too
> much. PCB&F seem to stick with a ratio here of keel midships beam
to
> depth of 2/1. Of course this would also reduce the head-room/lower-
> windage benefits of your suggested 2' x 2' cross section, but then
> it also reduces the 2' x 2' extra volume bouyancy/ballast problem.
>
> You might get away with the head room increasing keel depth sought,
> but I'd be wary of Bolger's oft stated observation that deep hulls
> increase wavemaking / shallow hulls reduce wavemaking. Perhaps the
> deeper keel made much narrower, just enough for the feet, might
> reduce keel resistance as per catamaran style?
>
> The easiest thing to do would be to write PCB&F and ask. But two
> small Micro hull models, say 1/10 scale, each strung from a balance
> beam in turn strung from a rod that is held out from a swimming
pool
> edge as you walk along the side might also be revealing. The
control
> model according to plan, the other without the designed salient
keel
> so that variously dimensioned box keels might be easily fitted
under
> it. Weigh them each down to the designed water line. Offset the
> ballast weight sufficient to induce the heel as when under sail.
> Post many photos ;)
>
> cheers
> Graeme
>
>
>
>
>
> --- Inbolger@yahoogroups.com, BllFs6@ wrote:
> >
> > In a message dated 3/21/2006 10:40:19 AM Central Standard Time,
> > bruce@ writes:
> >
> > A box keeled hull modification to a Micro? Well, it wouldn't be
> a Micro.
> > Geez, did I say that it would still be one?
> >
> > The biggest thing you may not have thought of, is that you are
> describing
> > what seems to be roughly 50 cubic feet of displacment, which
> would need
> > 3,000+ pounds of added ballast.
> > Actually, that part did cross my mind, but I'd say you are off by
> about a
> > factor of 2, which means the box keel alone could "float" the
> whole micro.
> > Remember its a 2 by 2 by 15 foot tapered "bolgeriod", not a 2 by
2
> by 15 hollow
> > rectangle
> >
> > Some fixes to get some of the original Micro hull in the water a
> foot or so
> > give or take...assuming that would actually be a requirement
> for "better"
> > perfomance...
> >
> >
> > Extra weight down low....improves sail performance under
> conditions XYZ?....
> > or allows more sail area? ....etc etc...
> >
> > Besides say an area 2 foot fore and 2 foot aft of the cabin
> doorway for
> > standing purposes, allow the rest of keel to be floodable...ie
the
> rest of the
> > keel shape is there to do what keels do for sailboats, and it has
> a shape that
> > hopefully minimizes drag given its sailing and ergonomic
> requirements (which
> > is why its there in the first place)...
> >
> > The (mostly) floodable keel could have 2 advantages....keep it
dry
> to make
> > trailer launching easier....pump it dry at sea to get ungrounded
> or for travel
> > over shallow regions....
> >
> > This keel would also be a good place to put heavy stuff such a
> battery or 2,
> > anchor chains, heavy tools, dense supplies etc etc.....
> >
> > The slighter deeper fat box keel, as compared to the regular
thin
> micro
> > keel, would also allow ballast mass to get place lower down....
> >
> > The deeper keel would also provide more lateral area for a keel
> to do what
> > it supposed to do....
> >
> > The keel, with its ability to provide bouyancy, could/would allow
> for more
> > cargo or total ballast mass to be carried....
> >
> > I guess my main question is would these things that could
possibly
> make the
> > boat a "better" sailboat be negated by the fact you have a "fat"
> keel thats
> > roughly 2 feet wide in the center rather than a similiar keel
> thats only a a
> > few inches wide...
> >
> >
> >
> >
> >
> > A standard Micro needs 400 pounds of ballast to float to her
> waterline.
> >
> > Knew that...see above...
> >
> >
> >
> > FWIW, adding a navigator cabin, like I did, gives standing
> headroom.
> >
> > true, but thats added mass up high, larger area for wind to work
> on above
> > the water line and doesnt really allow you sit behind the cabin
in
> the cockpit
> > and see foward freely
> >
> > The navigator cabin makes perfect sense if you like
being "inside"
> more, and
> > have a fair bit of foul weather to deal with...
> >
> > My suggestion makes more sense if the weather is mostly good, and
> you really
> > just want to stand up inside on the rare occasions that you need
> to for
> > getting dressed, stretching your back, using the porta pottie etc
> etc....
> >
> >
> > Cabin vs "deep/fat keel"....different strengths/weaknesses for
> different
> > requirements/conditions......
> >
> > Again, iffffffff a fat/wide keel isnt a real perfomance
> killer....
> >
> >
> >
> >
> >
> > Also, you use the expression 'sailing performance' without
> defining
> > what you mean. There are lots of different criteria to measure
> > sailing performance. Cruising qualities, racing qualities,
> > safety qualities, light air, reefing, economics, beauty, and
> more...
> >
> > That why I ask...as I am sure this fat keel could be good under
> some
> > conditions and bad in others....my question is under which
> ones....and how much? 1
> > percent, 10? 50?.....
> >
> > I am not really concerned about racing, beauty, or
> economics.....and I cant
> > really see how safetly would be largely impacted by such a design
> if properly
> > implemented.
> >
> > Just basic sailing speed penalties/benifits......ie how much
> faster/slower
> > am I going to cruise under conditions XYZ.....
> >
> > Sure, this design would be a bit harder to build, cost a bit
more,
> and
> > probably have a bit more draft that a regular micro....but I
think
> the ability to
> > stand (without going the cabin option way) would be worth these
> downsides....
> >
> > Again, I think the big deal maker/breaker would be the sail
> performance of
> > such a fat/wide keel...
> >
> >
> > thanks for the input!
> >
> > Blll
> >
> >
> > [Non-text portions of this message have been removed]
> >
>
> depth of 2/1. Of course this would also reduce the head-room/lower-
> windage benefits of your suggested 2' x 2' cross section, but then
> it also reduces the 2' x 2' extra volume bouyancy/ballast problem.

I bet, an easier way to get headroom would be to add a 2'x2'x2'
doghouse box above the cuddy hatch.
>--- In bolger@yahoogroups.com, "mannthree" <johnmann@...> wrote:
> There is a design called "Brendan the Navigator" that is almost
> exactly what you are describing. I think there has been some
> discussion on this group and others (Try Microcruising)

Pdf at group Microcruisingpics files -
http://groups.yahoo.com/group/Microcruisingpics/files/Brendan%20the%
20Navigator.pdf

Graeme
>Could such a design if done properly match or exceed the sailing
>performance of the regular micro design under some/many/most/all
>conditions.If perfomance was lessened, how significant would it be?

If increased sailing performance means you want faster then I
suspect PCB would simply refer you to a longer design, say Long
Micro, as the most efficient solution. However, that not
withstanding, I think PCB&F have proven to themselves satisfactorily
enough that the box keel cutwater does improve sailing qualities of
heavy types. Speed is increased by shifting displacement to the ends
and lessening the hull from bogging down in its own waves. Unless
built in materials heavier than plywood your suggestion of mostly
flooding the keel would seem simplest. However, your suggested
dimensions and proportions may need some adjustment as comparing,
approximately, Micro of 15'LOA by 6'Beam to Col H G Hasler of 20' by
8' we have the same relative proportions. Reducing the Col H G
Hasler box keel proportions by the same 3/4 ratio would have it for
Micro at 18" midships beam by 9" midships depth below the main hull
bottom (this is not total draft). In approximately comparing Micro
of 15'LOA by 6'Beam to Brick "Flying Cloud" of 8' by 4' we have
ratios for LOA of ~1/2 and Beam of 2/3. Pick your choice of scaling
ratios for the Brick "Flying Cloud" box keel beam of 15" by 7-3/16"
depth to give Micro box keel midships dimensions of 2'6" by 14-3/8",
or 22.5" by 11-1/16".

So from the Bolger rule bending ratios Micro box keel midships
dimensions might be any of 18"Beam x 9"Depth, 30" x 14-3/8", or 22-
1/2" x 11-1/16".

I'd be inclined to say the Col H G Hasler is best as main hull
proportions are the same, and "Flying Cloud" was a test... but then
there is that ~60 degree deadrise to consider. The real problem is
that whichever ratio is used your proposed depth of 2' is way too
much. PCB&F seem to stick with a ratio here of keel midships beam to
depth of 2/1. Of course this would also reduce the head-room/lower-
windage benefits of your suggested 2' x 2' cross section, but then
it also reduces the 2' x 2' extra volume bouyancy/ballast problem.

You might get away with the head room increasing keel depth sought,
but I'd be wary of Bolger's oft stated observation that deep hulls
increase wavemaking / shallow hulls reduce wavemaking. Perhaps the
deeper keel made much narrower, just enough for the feet, might
reduce keel resistance as per catamaran style?

The easiest thing to do would be to write PCB&F and ask. But two
small Micro hull models, say 1/10 scale, each strung from a balance
beam in turn strung from a rod that is held out from a swimming pool
edge as you walk along the side might also be revealing. The control
model according to plan, the other without the designed salient keel
so that variously dimensioned box keels might be easily fitted under
it. Weigh them each down to the designed water line. Offset the
ballast weight sufficient to induce the heel as when under sail.
Post many photos ;)

cheers
Graeme





--- Inbolger@yahoogroups.com, BllFs6@... wrote:
>
> In a message dated 3/21/2006 10:40:19 AM Central Standard Time,
> bruce@... writes:
>
> A box keeled hull modification to a Micro? Well, it wouldn't be
a Micro.
> Geez, did I say that it would still be one?
>
> The biggest thing you may not have thought of, is that you are
describing
> what seems to be roughly 50 cubic feet of displacment, which
would need
> 3,000+ pounds of added ballast.
> Actually, that part did cross my mind, but I'd say you are off by
about a
> factor of 2, which means the box keel alone could "float" the
whole micro.
> Remember its a 2 by 2 by 15 foot tapered "bolgeriod", not a 2 by 2
by 15 hollow
> rectangle
>
> Some fixes to get some of the original Micro hull in the water a
foot or so
> give or take...assuming that would actually be a requirement
for "better"
> perfomance...
>
>
> Extra weight down low....improves sail performance under
conditions XYZ?....
> or allows more sail area? ....etc etc...
>
> Besides say an area 2 foot fore and 2 foot aft of the cabin
doorway for
> standing purposes, allow the rest of keel to be floodable...ie the
rest of the
> keel shape is there to do what keels do for sailboats, and it has
a shape that
> hopefully minimizes drag given its sailing and ergonomic
requirements (which
> is why its there in the first place)...
>
> The (mostly) floodable keel could have 2 advantages....keep it dry
to make
> trailer launching easier....pump it dry at sea to get ungrounded
or for travel
> over shallow regions....
>
> This keel would also be a good place to put heavy stuff such a
battery or 2,
> anchor chains, heavy tools, dense supplies etc etc.....
>
> The slighter deeper fat box keel, as compared to the regular thin
micro
> keel, would also allow ballast mass to get place lower down....
>
> The deeper keel would also provide more lateral area for a keel
to do what
> it supposed to do....
>
> The keel, with its ability to provide bouyancy, could/would allow
for more
> cargo or total ballast mass to be carried....
>
> I guess my main question is would these things that could possibly
make the
> boat a "better" sailboat be negated by the fact you have a "fat"
keel thats
> roughly 2 feet wide in the center rather than a similiar keel
thats only a a
> few inches wide...
>
>
>
>
>
> A standard Micro needs 400 pounds of ballast to float to her
waterline.
>
> Knew that...see above...
>
>
>
> FWIW, adding a navigator cabin, like I did, gives standing
headroom.
>
> true, but thats added mass up high, larger area for wind to work
on above
> the water line and doesnt really allow you sit behind the cabin in
the cockpit
> and see foward freely
>
> The navigator cabin makes perfect sense if you like being "inside"
more, and
> have a fair bit of foul weather to deal with...
>
> My suggestion makes more sense if the weather is mostly good, and
you really
> just want to stand up inside on the rare occasions that you need
to for
> getting dressed, stretching your back, using the porta pottie etc
etc....
>
>
> Cabin vs "deep/fat keel"....different strengths/weaknesses for
different
> requirements/conditions......
>
> Again, iffffffff a fat/wide keel isnt a real perfomance
killer....
>
>
>
>
>
> Also, you use the expression 'sailing performance' without
defining
> what you mean. There are lots of different criteria to measure
> sailing performance. Cruising qualities, racing qualities,
> safety qualities, light air, reefing, economics, beauty, and
more...
>
> That why I ask...as I am sure this fat keel could be good under
some
> conditions and bad in others....my question is under which
ones....and how much? 1
> percent, 10? 50?.....
>
> I am not really concerned about racing, beauty, or
economics.....and I cant
> really see how safetly would be largely impacted by such a design
if properly
> implemented.
>
> Just basic sailing speed penalties/benifits......ie how much
faster/slower
> am I going to cruise under conditions XYZ.....
>
> Sure, this design would be a bit harder to build, cost a bit more,
and
> probably have a bit more draft that a regular micro....but I think
the ability to
> stand (without going the cabin option way) would be worth these
downsides....
>
> Again, I think the big deal maker/breaker would be the sail
performance of
> such a fat/wide keel...
>
>
> thanks for the input!
>
> Blll
>
>
> [Non-text portions of this message have been removed]
>
--- Inbolger@yahoogroups.com, BllFs6@... wrote:
>Bill,

There is a design called "Brendan the Navigator" that is almost
exactly what you are describing. I think there has been some
discussion on this group and others (Try Microcruising) of this boat.
It was built in aluminium by Larry ???? and has a lateen rig. I
know there have been several articles in "Small Craft Advisor" on this
boat. It is not a Micro "conversion" but a distinctly new design with
Micro attributes. Perhaps some of the more knowledgeable members can
give more details,

Regards,

John Mann
> Hi all...
>
> Have a what if design kind of question.
>
>
> Lets take Bolger's Micro design.
>
> Remove the keel.
>
> Make a box? keel. This keel would have a "U" cross sectional shape,
like the
> boat itself.
>
> This keel would be say roughly 2 feet deep/tall by 2 feet wide in
the area
> right near the center of the boat. It would taper down in width and
depth,
> coming to a "point" near/at the bow of the boat. It would taper down
in width
> mostly headed in the stern direction.
>
> The whole point of this would be to give a small area just inside
the cabin,
> as well as perhaps just outside the cabin (with say a canvas or
hardtop
> overhang) in which you could stand fully erect. A small thing
perhaps, but
> possibly a big comfort improving feature for some folks at least.
>
> Could such a design if done properly match or exceed the sailing
performance
> of the regular micro design under some/many/most/all conditions. If
> perfomance was lessened, how significant would it be?
>
> Any comments?
>
> thanks
>
> Blll
>
>
> [Non-text portions of this message have been removed]
>
>FWIW, adding a navigator cabin, like I did, gives standing headroom.

OK so for it's worth.
MY boat is not a bolger micro navigator by a long shot but the cabin
is dead on. Don seems to live in a mangronve swamp with oink(?) and
loves his(must be a bug thing) while Bruce is in the pacific NW so he
seems to dig his (rightly so).

Mine is in costal NC tied up at a dock. It flirts with the 80's now
and then and it's still march.......the boat is hot regardless of down
draft from the sail, front hatches all open (set to scoop)and tinted
plexiglass all around. The boat sails pretty good till about 15 knots
and then get's scary if you don't reef quick......i've got a bigggggg
mainsail. With the boat reefed down the pilot house commences to catch
the wind like a freeking genoa making the boat shall we say un
predictable, but it will run hull speed down wind under bare pole in
18 knots.....kinda cool till i try and dock(winds usually come from
the south here and my slip dead ends due north with a concrete
bulkhead.

As soon as the weather breaks for good the cabin is gone, the sawzall
is charged and waiting. Going to cut right up to the beam at the base
of the forward three windows which will leave a tiny cuddy with a
drip/toe hold already in place .....i've got a little dodger sketched
out and have already welded up some SS tie downs for a boom tent,
shoud be neat. Who am i kidding when it rains I don't go sailing.

Jason
>like , 20ft _Col. HG Hassler_ , also 22ft _Small Motor Sailer_.
But
>in both cases he has added a chine for deadrise (probably to
mitigate
>the displacement mass issue).

I wonder if the lack of deadrise on a microesque boat with box keel
would slap like hell when sailed on ear?

I know flying cloud is one third the boat but it's closer to a box
keel micro than the hasler. Have you read that article? in the files
somewhere.

Jason Stancil
> A box keeled hull modification to a Micro? Well, it wouldn't be a Micro.
> Geez, did I say that it would still be one?

I misinterpreted your subject line: "Micro with box keel...", sorry.

> The biggest thing you may not have thought of, is that you are describing
> what seems to be roughly 50 cubic feet of displacment, which would need
> 3,000+ pounds of added ballast.
> Actually, that part did cross my mind, but I'd say you are off by about a
> factor of 2,

Adding 1,500lbs plus 400lbs for ballast in a 15 boat is still rather
massive, flooding parts of the keel would help the trailer weight, and
certainly you would have no trouble getting through stays, but with no
brakes be careful not to ram into anything!

> hopefully minimizes drag

In my experience, the limiting factor with a Micro is the drag of
displacement hull speed caused by the short length. Efforts to
improve the other kinds of drag are wasted. In short, it doesn't take
much wind to get all she can give.

Bolger has designed small boats exploiting a box keel for headroom
like , 20ft _Col. HG Hassler_ , also 22ft _Small Motor Sailer_. But
in both cases he has added a chine for deadrise (probably to mitigate
the displacement mass issue).
In a message dated 3/21/2006 10:40:19 AM Central Standard Time,
bruce@...writes:

A box keeled hull modification to a Micro? Well, it wouldn't be a Micro.
Geez, did I say that it would still be one?

The biggest thing you may not have thought of, is that you are describing
what seems to be roughly 50 cubic feet of displacment, which would need
3,000+ pounds of added ballast.
Actually, that part did cross my mind, but I'd say you are off by about a
factor of 2, which means the box keel alone could "float" the whole micro.
Remember its a 2 by 2 by 15 foot tapered "bolgeriod", not a 2 by 2 by 15 hollow
rectangle

Some fixes to get some of the original Micro hull in the water a foot or so
give or take...assuming that would actually be a requirement for "better"
perfomance...


Extra weight down low....improves sail performance under conditions XYZ?....
or allows more sail area? ....etc etc...

Besides say an area 2 foot fore and 2 foot aft of the cabin doorway for
standing purposes, allow the rest of keel to be floodable...ie the rest of the
keel shape is there to do what keels do for sailboats, and it has a shape that
hopefully minimizes drag given its sailing and ergonomic requirements (which
is why its there in the first place)...

The (mostly) floodable keel could have 2 advantages....keep it dry to make
trailer launching easier....pump it dry at sea to get ungrounded or for travel
over shallow regions....

This keel would also be a good place to put heavy stuff such a battery or 2,
anchor chains, heavy tools, dense supplies etc etc.....

The slighter deeper fat box keel, as compared to the regular thin micro
keel, would also allow ballast mass to get place lower down....

The deeper keel would also provide more lateral area for a keel to do what
it supposed to do....

The keel, with its ability to provide bouyancy, could/would allow for more
cargo or total ballast mass to be carried....

I guess my main question is would these things that could possibly make the
boat a "better" sailboat be negated by the fact you have a "fat" keel thats
roughly 2 feet wide in the center rather than a similiar keel thats only a a
few inches wide...





A standard Micro needs 400 pounds of ballast to float to her waterline.

Knew that...see above...



FWIW, adding a navigator cabin, like I did, gives standing headroom.

true, but thats added mass up high, larger area for wind to work on above
the water line and doesnt really allow you sit behind the cabin in the cockpit
and see foward freely

The navigator cabin makes perfect sense if you like being "inside" more, and
have a fair bit of foul weather to deal with...

My suggestion makes more sense if the weather is mostly good, and you really
just want to stand up inside on the rare occasions that you need to for
getting dressed, stretching your back, using the porta pottie etc etc....


Cabin vs "deep/fat keel"....different strengths/weaknesses for different
requirements/conditions......

Again, iffffffff a fat/wide keel isnt a real perfomance killer....





Also, you use the expression 'sailing performance' without defining
what you mean. There are lots of different criteria to measure
sailing performance. Cruising qualities, racing qualities,
safety qualities, light air, reefing, economics, beauty, and more...

That why I ask...as I am sure this fat keel could be good under some
conditions and bad in others....my question is under which ones....and how much? 1
percent, 10? 50?.....

I am not really concerned about racing, beauty, or economics.....and I cant
really see how safetly would be largely impacted by such a design if properly
implemented.

Just basic sailing speed penalties/benifits......ie how much faster/slower
am I going to cruise under conditions XYZ.....

Sure, this design would be a bit harder to build, cost a bit more, and
probably have a bit more draft that a regular micro....but I think the ability to
stand (without going the cabin option way) would be worth these downsides....

Again, I think the big deal maker/breaker would be the sail performance of
such a fat/wide keel...


thanks for the input!

Blll


[Non-text portions of this message have been removed]
> Could such a design if done properly match or exceed the sailing performance
> of the regular micro design under some/many/most/all conditions. If
> perfomance was lessened, how significant would it be?
>
> Any comments?

A box keeled hull modification to a Micro? Well, it wouldn't be a Micro.

The biggest thing you may not have thought of, is that you are describing
what seems to be roughly 50 cubic feet of displacment, which would need
3,000+ pounds of added ballast.

A standard Micro needs 400 pounds of ballast to float to her waterline.

FWIW, adding a navigator cabin, like I did, gives standing headroom.

Also, you use the expression 'sailing performance' without defining
what you mean. There are lots of different criteria to measure
sailing performance. Cruising qualities, racing qualities,
safety qualities, light air, reefing, economics, beauty, and more...
Hi all...

Have a what if design kind of question.


Lets take Bolger's Micro design.

Remove the keel.

Make a box? keel. This keel would have a "U" cross sectional shape, like the
boat itself.

This keel would be say roughly 2 feet deep/tall by 2 feet wide in the area
right near the center of the boat. It would taper down in width and depth,
coming to a "point" near/at the bow of the boat. It would taper down in width
mostly headed in the stern direction.

The whole point of this would be to give a small area just inside the cabin,
as well as perhaps just outside the cabin (with say a canvas or hardtop
overhang) in which you could stand fully erect. A small thing perhaps, but
possibly a big comfort improving feature for some folks at least.

Could such a design if done properly match or exceed the sailing performance
of the regular micro design under some/many/most/all conditions. If
perfomance was lessened, how significant would it be?

Any comments?

thanks

Blll


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