Re: [bolger] Re: Micro's weight vs. plywood thickness
Hi Pippo,
I suspected! In fact, last week I tried to look at the 18mm panels in the
lumberyard, just to make a quick bending test... but the stand was empty.
Probably with steam... no, seems too complicate. I think I will go with the
usual way (double bottom).
I'm grateful for your advice.
Francisco
Giuseppe Bianco wrote:
I suspected! In fact, last week I tried to look at the 18mm panels in the
lumberyard, just to make a quick bending test... but the stand was empty.
Probably with steam... no, seems too complicate. I think I will go with the
usual way (double bottom).
I'm grateful for your advice.
Francisco
Giuseppe Bianco wrote:
> Ciao Francisco
> well, with the rocker of the Micro bottom you won't be able to bend
> that thick plywood, and the butt blocks are going to be a mess...
> I'll laminate two layers of 9 mm...
> Best
>
> Pippo
>
Ciao Francisco
well, with the rocker of the Micro bottom you won't be able to bend
that thick plywood, and the butt blocks are going to be a mess...
I'll laminate two layers of 9 mm...
Best
Pippo
--- Inbolger@egroups.com, Francisco Ramírez <astrolabio@s...>
wrote:
(18 mm)
well, with the rocker of the Micro bottom you won't be able to bend
that thick plywood, and the butt blocks are going to be a mess...
I'll laminate two layers of 9 mm...
Best
Pippo
--- Inbolger@egroups.com, Francisco Ramírez <astrolabio@s...>
wrote:
> List,3/4"
>
> Any concerns about using a single piece (four single pieces) of
(18 mm)
> in Micro's bottom?
>
> The rest of my boat is 3/8"
>
> Thanks.
>
> Francisco
> (looking for a place to go 3D with my hull next month)
List,
Any concerns about using a single piece (four single pieces) of 3/4" (18 mm)
in Micro's bottom?
The rest of my boat is 3/8"
Thanks.
Francisco
(looking for a place to go 3D with my hull next month)
Any concerns about using a single piece (four single pieces) of 3/4" (18 mm)
in Micro's bottom?
The rest of my boat is 3/8"
Thanks.
Francisco
(looking for a place to go 3D with my hull next month)
Bill & Pippo:
Time for me to walk the plank. This is how I do it:
The only thing that changes with a thicker skin is that you
can add weight equivalent to the extra bouancy.
If you add a cubic foot of Occume outside the original lines
of a boat, it weighs 30 pounds, or 13.63 kg.. That will
displace 60
pounds of water.
By rough and ready measure, total surface area for Micro's
sides and bottom runs at 150 sq. ft., but the part
below the waterline is only 80 sq. ft.. If you add an extra
1/8th inch of Occume to the skin then, the part out of
the water weighs an extra 20# (9.09 kg), and the part that's
in is 25 (11.3 kg).
But the amount of water moved weighs twice that, 50# or 22.7
kilograms. So you get 5# extra bouancy (2+ kg). Not enough
to matter, but
the extra 45 pounds was floated without any trouble.
You can't do this without practical limit because of how
much sail area you've got, and in the extreme I think,
because no
matter how good the boost, you're up against the pounds per
inch immersion of the total shape. But the figures for dead
weight trailoring might be more congenial than I guessed
at first.
This was not as much bouancy gain as I expected when
reaching for a calculator. The high freeboard of a Square
Boat wipes out some of it.
On a larger scale, I notice in the current WB there's an
article on constructing a DD 38. This is normally built
with 12mm skin and 6mm interior joinery. He says if you
build it with an 18mm skin, bouancy increases to allow
using 9mm inside.
Put simply: "If this is done by increasing
the thickness outward rather than inward, the extra
structural weight is carried by the increased hull volume,
so she will not sit deeper despite the greater strength."
(Dudley Dix)
Happy as I go,
Mark
Time for me to walk the plank. This is how I do it:
The only thing that changes with a thicker skin is that you
can add weight equivalent to the extra bouancy.
If you add a cubic foot of Occume outside the original lines
of a boat, it weighs 30 pounds, or 13.63 kg.. That will
displace 60
pounds of water.
By rough and ready measure, total surface area for Micro's
sides and bottom runs at 150 sq. ft., but the part
below the waterline is only 80 sq. ft.. If you add an extra
1/8th inch of Occume to the skin then, the part out of
the water weighs an extra 20# (9.09 kg), and the part that's
in is 25 (11.3 kg).
But the amount of water moved weighs twice that, 50# or 22.7
kilograms. So you get 5# extra bouancy (2+ kg). Not enough
to matter, but
the extra 45 pounds was floated without any trouble.
You can't do this without practical limit because of how
much sail area you've got, and in the extreme I think,
because no
matter how good the boost, you're up against the pounds per
inch immersion of the total shape. But the figures for dead
weight trailoring might be more congenial than I guessed
at first.
This was not as much bouancy gain as I expected when
reaching for a calculator. The high freeboard of a Square
Boat wipes out some of it.
On a larger scale, I notice in the current WB there's an
article on constructing a DD 38. This is normally built
with 12mm skin and 6mm interior joinery. He says if you
build it with an 18mm skin, bouancy increases to allow
using 9mm inside.
Put simply: "If this is done by increasing
the thickness outward rather than inward, the extra
structural weight is carried by the increased hull volume,
so she will not sit deeper despite the greater strength."
(Dudley Dix)
Happy as I go,
Mark
> Giuseppe Bianco wrote:
> >
> > Bill - I'm not quite sure what you're referring to. I don't think
> > that anything is gonna changing with thicker plywood. From a very
> > rough computation, the submerged volume would change of something of
> > the order of 20 liters, with a constant waterline level. Doesn't make
> > any difference to me.
> > Best
> >
> > Pippo
> >
> > --- Inbolger@egroups.com, wmrpage@a... wrote:
> >
> > > This is a purely academic question, but is it possible that you
> > > "Miro-nauts" are comparing apples and oranges? Would the difference
> > in
> > > displacement caused by floating a thicker hulled "Micro" to its
> > designed
> > > water line account for something more that the gross weight
> > increase
> > of
> > > thicker material? Just a thought.
> > >
> > > Bill in MN
> >