Boat Forum / Boats / July 2008

This is a bad idea on several levels. Even if you can make the math
seem to work, the hull is designed to sit at a certain level in the
water so as to be safe during all aspects of operation while cruising
or in emergency conditions. Pitch a tent up there, or get a different
boat. It's like pulling a trailer that is too heavy for the vehicle.
The vehicle might get it rolling, but in an emergency can't react the
way you want it to, or the way it was designed.. You might get away
with it for years, but it could also get you killed in seconds. In a
nutshell, you have the wrong tool for the job. Change your plan, or
get a different boat... Just my opinion, but I am always against
modifying a tried and tested design..

Scotty
SmallBoats.com

That hull doesn't weigh as much as you think it does. Plus, it's
essentially flat which, while counter-intuitive, makes it less stable.

Alll boats and ships obey two laws of physics - center of buoyancy
(CB) which is the center of the underwater volume of the vessel and
center of gravity (CG) which is where all the mass would be
concentrated if it had to be compressed to a single point.  To float
properly on the design waterline, then the CG must be in line
vertically with the CB.

Once you start messing around with CG (which is essentially what you
are doing), it throws off the CB (because they are interrelated) and
you are constantly playing catch-up to keep it properly oriented (dry
side up and wet side down).  Even adding 300 pounds isn't going to
affect anything much because your CB, which is not a constant and can
change depending on any number of factors, is out of whack.

Additionally, you have to worry about beam - it ain't got none to
speak of.

You can figure it all out if you really want to.

http://www.johnsboatstuff.com/Articles/estimati.htm

Good luck.

Did I miss something here It's a POS  sink it.

<snip>

THIS is top-heavy:
http://images.thebiggestbreasts.com/post/20070820/humongous_fake_boobs.jpg

Caution: nudity. Adults only please.

--
Gregory Hall

Use a tent! The thing will add only 20lbs to the boat, is easy to remove,
and can be configured all kinds of ways. Check LLBean for a tent that will
fit. Put a couple thermarest mattresses on the deck and you're good to go.

David,
Get a book on Naval Architecture and read about GM.
Every boat has the center of gravity above the center of buoyancy.
Weight added alone might not keep it upright.
Matt Colie

Well, boat stability is a complex subject. Here
some loose thoughts (before my first cup of coffee,
so no guarantees that I get all things right. I'm
sure others will jump on the chance to correct my
worst blunders - maybe I can learn something too!)

I would recommend you read a bit more about it. The
"Nature of Boats" by Dave Gerr is a good all-around
introduction, and doesn't get too technical. Many
other books work as well.

When you add weight and windage high up, you reduce
the stability. That increases the risk that your boat
will capsize in high seas (or even in flat water). It
also changes the way the boat rolls in seas, which may
make it more or less comfortable to be inside.

You are right, you can compensate by adding weight (as
low as possible!). This will make the boat sit deeper
in the water. Maybe too deep.

It all depends what you are going to use the boat for.
With a solid house on it, and enough ballast to keep her
upright, she will not want to plane. If you can live with
moving her at hull speed (a few knots), you can make do
with *much* smaller engine, and use the weight difference
as ballast. If you do not plan to move her around much at
all, then you can afford to load he a bit deeper, as the
sailing characteristics won't matter.

You can probably get an idea of the stability by doing a
simple roll period test. Rock the boat sideways, it will
settle on some speed of rolling from side to side. If
this roll time (in seconds) is the same as your overall
beam (in meters), (or 10% more), you have what Gerr
describes a good initial stability. If the boar rolls
much faster, you have more (initial) stability for
good comfort - that would be good news for you. If,
after all the construction, your boat rolls slower than
this, you may want to add some ballast.

In any case, keep the structure as low as you can manage,
and build it light! It looks like a small boat to begin
with, so don't even try to build a large house on her.
Keep it small and simple, and might work well.

Remember that a boat is always a compromise. A heavily
modified boat is a compromise between the original
compromiseand a your new ideas. It is your own boat,
and it is you who will have to live with it. Don't let
us naysayers put you completely off. But watch out, it
is also your own life you are risking, and possibly your
dear ones as well!

Good luck!

 -Heikki

Judging from friends' boats of about that configuration, I'd suggest
something quite a bit lighter: a light hard roof and tarps, screen and
plastic for  removable "walls", a pop-top camper of sorts.

That said, a friend was for a time a "slum landlord" of a number of
"floating structures" in Key West that were about what I hear you
saying. They (mostly) stayed afloat for some years and weathered some
nasty weather.

Have to say that the inhabitants were not thought well of, though, and
the "boats" uniformly disliked by all. Ugly doesn't begin to say it.

Pontoon boats make pretty good house boats. I checked out a 22' that the
owner had built up about 2/3s the deck space with house and a patio roof
over the open front. He used that sandwiched foam/aluminum patio roofing and
it came out real well. Kinda looked like a floating trailer, but it served
his purposes.