Re: PVC tubing
> "Cliff's shanty boat" should read, "Cliff's theoretical shantyboat."Shanty boat, Fantasy boat? It doesn't matter. I was having fun
> It's still in the fantasy stage.
fiddling with the idea of how to float one.
> A sauna on floats, with a nice seat, a wood burner and a pile ofNow there's an idea!
> rocks inside. The dealer told me it used to sail regularly on the
> lake,
Ray
"Cliff's shanty boat" should read, "Cliff's theoretical shantyboat."
It's still in the fantasy stage.
Speaking of fantasies...I saw evidence of one come true earlier this
summer. Visiting a boat dealer's back yard, I spied what appeared to be
an old shantyboat back in the rear. Up close, the structure seemed
rather small. Opening the door I discovered why; it was a neatly built
sauna! A sauna on floats, with a nice seat, a wood burner and a pile of
rocks inside. The dealer told me it used to sail regularly on the lake,
Portage Lake in Michigan.
Cliff
http://www.angelfire.com/mi/mmmkkk/
(Last of the Red Hot DJs)
It's still in the fantasy stage.
Speaking of fantasies...I saw evidence of one come true earlier this
summer. Visiting a boat dealer's back yard, I spied what appeared to be
an old shantyboat back in the rear. Up close, the structure seemed
rather small. Opening the door I discovered why; it was a neatly built
sauna! A sauna on floats, with a nice seat, a wood burner and a pile of
rocks inside. The dealer told me it used to sail regularly on the lake,
Portage Lake in Michigan.
Cliff
http://www.angelfire.com/mi/mmmkkk/
(Last of the Red Hot DJs)
Lincoln,
I've given it some more thought...
the beauty of using poly barrels comes into play. Cliff hasn't said
how big his shanty boat is but I'll guess it's big enough to use 55
gallon barrels for floatation. If it's not then all the arguments
for poly barrels are moot.
1 barrel = 55 gallons
1 gallon = 0.134 cubic ft
1 cubic ft sea water = 64 lbs
In sea water each barrel displaces 55 * 0.134 * 64 = 471 lbs
Assume a poly barrel weighs (I'm just guessing here) 10 lbs
Net floatation per poly barrel is 471 - 10 = 461 lbs seawater
There's not much floataion lost to material weight.
Go back to the idea of using PVC pipe and material weight does matter
more. I'll assume a limited budget that can't afford the large
diameter instustrial PVC pipe. Rather he has to make do with what
Home Despot has, probably the biggest is 4" drainage pipe, thin wall
and fairly light.
So, a column of water 4" in diameter and 12" long displaces 150.72
cubic inches. 1 gallon = 231 cubic inches. One 55 gal barrel
displaces 55 * 231 = 12705 cubic inches. You would need 12705 /
150.72 = 84.25 linear feet of 4" PVC pipe to do the work of one
barrel, excluding material weight. It's hard to imagine 84.25 feet
of 4" pipe, even the thin wall drainage pipe, weighing just 10 lbs!
Probably more like 60 lbs (another guess). You'd still get 411 lbs
net floatation.
shanty boat will be big enough to be built like Merrell's barrel
boats. As I understand the info on Merrell's web site
http://www.boatdesign.com/pnutline.htm(I haven't seen plans or
talked to him) then the boat's structure provides the stiffness. The
barrels are captured by the boat and provide floatation only. Unlike
the traditional pontoon boat where the hulls are both structure and
floatation.
Puncturing the barrel is probably why Merrell fills his with foam. I
sure would on my boat, if for no other reason than you don't have to
rely on the rubber gaskets on the barrel bungs to remain watertight.
If you will be filling them with foam, remember to subtract the
weight of the foam to get net floatation.
which polysomething they are. I do know from experience they are
rugged, highly resistant to puncture and abrasion, not at all
bothered by petroleum products, and if you scrounge a bit very
cheap. I've paid as much as $15 each, or as little as the time and
effort to haul them away. My favorites are the barrels discarded by
hospitals that were used to hold alcohol. All you have to do is
remove the bungs and let them sit in the sun for a few days and you
have a perfectly clean barrel.
The bit about resistance to petroleum is important. In the 70's when
Seattle's older house boats, the ones floating on cedar logs, were
being restored some were placed on styrofaom blocks. All was well
until a boat spilled gas disolving the foam and endangering the house
boats! Whatever material is used, it must be resistant to gas and
oil.
This not a endorsement of the use of poly barrels for a boat that
will be underway much. I'd expect the drag of the barrels would be a
serious performance problem. And the worrry about keeping them
secured in any kind of weather would be more than I'd want to
stomach. For that kind of boat I'd look for a different solution all
together. Perhaps closed cell foam blocks skinned with fiberglass to
create pontoons? Or maybe there are some instustial strength
fiberglass cylingers that can be capped on the ends to create
pontoons?
Ray
I've given it some more thought...
> Actually, you can only use the flotation that's left over after youTrue, but so is the volume displaced for the weight. That's where
> lift the material itself, so weight of material is very relevant.
the beauty of using poly barrels comes into play. Cliff hasn't said
how big his shanty boat is but I'll guess it's big enough to use 55
gallon barrels for floatation. If it's not then all the arguments
for poly barrels are moot.
1 barrel = 55 gallons
1 gallon = 0.134 cubic ft
1 cubic ft sea water = 64 lbs
In sea water each barrel displaces 55 * 0.134 * 64 = 471 lbs
Assume a poly barrel weighs (I'm just guessing here) 10 lbs
Net floatation per poly barrel is 471 - 10 = 461 lbs seawater
There's not much floataion lost to material weight.
Go back to the idea of using PVC pipe and material weight does matter
more. I'll assume a limited budget that can't afford the large
diameter instustrial PVC pipe. Rather he has to make do with what
Home Despot has, probably the biggest is 4" drainage pipe, thin wall
and fairly light.
So, a column of water 4" in diameter and 12" long displaces 150.72
cubic inches. 1 gallon = 231 cubic inches. One 55 gal barrel
displaces 55 * 231 = 12705 cubic inches. You would need 12705 /
150.72 = 84.25 linear feet of 4" PVC pipe to do the work of one
barrel, excluding material weight. It's hard to imagine 84.25 feet
of 4" pipe, even the thin wall drainage pipe, weighing just 10 lbs!
Probably more like 60 lbs (another guess). You'd still get 411 lbs
net floatation.
> Strength and stiffness of the material are also very relevant,because
> the stronger and stiffer it is, the less you need. PVC is prettyabout
> floppy and not very strong. Big PVC tubes would have to be pretty
> heavy to be adequately strong, particularly if you are worried
> hitting rocks.In regards to stiffness, again making assumptions here, that Cliff's
shanty boat will be big enough to be built like Merrell's barrel
boats. As I understand the info on Merrell's web site
http://www.boatdesign.com/pnutline.htm(I haven't seen plans or
talked to him) then the boat's structure provides the stiffness. The
barrels are captured by the boat and provide floatation only. Unlike
the traditional pontoon boat where the hulls are both structure and
floatation.
Puncturing the barrel is probably why Merrell fills his with foam. I
sure would on my boat, if for no other reason than you don't have to
rely on the rubber gaskets on the barrel bungs to remain watertight.
If you will be filling them with foam, remember to subtract the
weight of the foam to get net floatation.
> Which poly? THere are a lot of different polysomethings, with a lotof
> different characteristics. Are these polyethylene barrels?Merrell seems to be using the industrial poly barrels. I don't know
> >
which polysomething they are. I do know from experience they are
rugged, highly resistant to puncture and abrasion, not at all
bothered by petroleum products, and if you scrounge a bit very
cheap. I've paid as much as $15 each, or as little as the time and
effort to haul them away. My favorites are the barrels discarded by
hospitals that were used to hold alcohol. All you have to do is
remove the bungs and let them sit in the sun for a few days and you
have a perfectly clean barrel.
The bit about resistance to petroleum is important. In the 70's when
Seattle's older house boats, the ones floating on cedar logs, were
being restored some were placed on styrofaom blocks. All was well
until a boat spilled gas disolving the foam and endangering the house
boats! Whatever material is used, it must be resistant to gas and
oil.
This not a endorsement of the use of poly barrels for a boat that
will be underway much. I'd expect the drag of the barrels would be a
serious performance problem. And the worrry about keeping them
secured in any kind of weather would be more than I'd want to
stomach. For that kind of boat I'd look for a different solution all
together. Perhaps closed cell foam blocks skinned with fiberglass to
create pontoons? Or maybe there are some instustial strength
fiberglass cylingers that can be capped on the ends to create
pontoons?
Ray
See below
--- In bolger@y..., raymcquin@y... wrote:
> Cliff,
>
> PVC should work just fine. Steel is heavier yet and is commonly
used
> in work boat construction. It's the volume displaced, not the
weight
> of the raw material that determines floatation.
Actually, you can only use the flotation that's left over after you
lift the material itself, so weight of material is very relevant.
Strength and stiffness of the material are also very relevant, because
the stronger and stiffer it is, the less you need. PVC is pretty
floppy and not very strong. Big PVC tubes would have to be pretty
heavy to be adequately strong, particularly if you are worried about
hitting rocks.
>
> If your shanty boat is large enough a cheap source of big volume
> displacement is scrap poly barrels.
Which poly? THere are a lot of different polysomethings, with a lot of
different characteristics. Are these polyethylene barrels?
>
snip
thanks
Cliff,
PVC should work just fine. Steel is heavier yet and is commonly used
in work boat construction. It's the volume displaced, not the weight
of the raw material that determines floatation.
If your shanty boat is large enough a cheap source of big volume
displacement is scrap poly barrels.
seehttp://www.boatdesign.com/pnutline.htmfor an example of a
largeish house boat using foam filled poly barrels for floatation.
Ray
PVC should work just fine. Steel is heavier yet and is commonly used
in work boat construction. It's the volume displaced, not the weight
of the raw material that determines floatation.
If your shanty boat is large enough a cheap source of big volume
displacement is scrap poly barrels.
seehttp://www.boatdesign.com/pnutline.htmfor an example of a
largeish house boat using foam filled poly barrels for floatation.
Ray
> I've been wondering if PVC might work as flotation for a Shantyboat
> platform. As someone said, it's heavy, so it would have to be large
> circumference.
>
> Cliff
>
>http://www.angelfire.com/mi/mmmkkk/
> (Last of the Red Hot DJs)
I've been wondering if PVC might work as flotation for a Shantyboat
platform. As someone said, it's heavy, so it would have to be large
circumference.
Cliff
http://www.angelfire.com/mi/mmmkkk/
(Last of the Red Hot DJs)
platform. As someone said, it's heavy, so it would have to be large
circumference.
Cliff
http://www.angelfire.com/mi/mmmkkk/
(Last of the Red Hot DJs)