My wife wants a Stand Up Paddleboard, she has never used one and neither have I.
We could rent one at the beach next summer to get some knowledge, but that means
a trip to the beach and I hate the beach... And I'm outta time.
I'm thinking I will build a Dynamite Sailboard hull for her for Christmas.

Has anyone ever used a SUP and can you comment on important attributes
for a SUP and if Dynamite board may be useable as a SUP?

I see CLC has a kit/plans for one that is close in length but a bit wider. CLC
board has a shallow Vee bottom, so probably a wash stability-wise (or should
that be awash ;-0)


It will just be for flat water lake use to start with.
If she likes it and wants one for waves I would probably buy her a "real" one
later if the Dynamite board won't work in low surf.

Justin

Hi Justin. I  used a Dynamite sailboard as a windsurfer back in about 1983 in
Florida.
   It worked well. Being longer than most windsurfers it sliced along nicely.
   It was stable enough for a  six foot 180 man to stand on easily.
   Two years ago I built an sup to my own design  but quite similar.
    It is 30 inches wide and 17 feet long and works well. HOWEVER.
it is very heavy. As Phil said, when you add a  deck you double the weight so
its much heavier than a kayak and therefore hard to move n shore.
   Instead of a deep fin like most commercial sups use I use a long fared in skeg
which allows it to go though weeds well. a big consideration. Also if you build
it airtight you need a vent to reliev air pressure or you can split the glass
taped chines.
     In addition I have found that SUPs are very wind sensitive. Downwind fine
but dont try to paddle to windward standing up wich of course means they  are
useless as a SUp half the time
   On the pro side however they paddle as well as a kayak when you are sitting
down so I keep a kayak paddle aboard at all times which doubles  your value. We
use it mainly to paddle through weeds to deeper water where we can swim then
climb back aboard. Something you cannot do from most kayaks.
   I would build a shrter and slghtly wider one next time with plentgy of rocker 
to keep the bow and tail from dragging. A simple hard chine design flat bottomed
works well.
    good luck, john

Should work. I built one, double ended, as a proa experiment. You can also sit
and paddle with a double paddle.

Whack-boing! It's dub!
www.thecheappages.com

Justin,

have you seen the current issue of Woodenboat magazine, there is an article with
design in there for a plywood SUP.

I hired a plastic SUP the other week for the first time.  I noted that it was
completely flat on the bottom with three little fin skegs, somewhat like some
surfboards.  It was wide, I am guessing 30", and the width was carried fore and
aft for most of it's length, making it more or less rectangular with rounded
ends.  This shape made for surprising stability and yet it tracked reasonably
well.  Windage was a problem - your body acts like a sail and it is hard work to
paddle upwind - keeping straight up wind was much harder than down wind.

I suspect the payson board is too narrow and tapered too much at the bow to be
an easy SUP.  I tried standing up on an old windsurfer board last year, about
24" wide but with tapering toward bow and stern and found it almost impossible.
you need that stability if your going to stand up and raise the centre of
gravity.

That said, all of my family enjoyed the sUP.

Andrew

--- In bolger@yahoogroups.com, "jdmeddock" <jmeddock@...> wrote:
>
>
> My wife wants a Stand Up Paddleboard, she has never used one and neither have
I.
> We could rent one at the beach next summer to get some knowledge, but that
means a trip to the beach and I hate the beach... And I'm outta time.
> I'm thinking I will build a Dynamite Sailboard hull for her for Christmas.
>
> Has anyone ever used a SUP and can you comment on important attributes
> for a SUP and if Dynamite board may be useable as a SUP?
>
> I see CLC has a kit/plans for one that is close in length but a bit wider. CLC
board has a shallow Vee bottom, so probably a wash stability-wise (or should
that be awash ;-0)
>
>
> It will just be for flat water lake use to start with.
> If she likes it and wants one for waves I would probably buy her a "real" one
later if the Dynamite board won't work in low surf.
>
> Justin
>

Maybe two more branches to add to this tree... There are other proas big and
small based pretty much on the hull shape but diverging in the rudder/leeway
and/or sail (sloop) treatment. However, if Cod's double ended Dynamite Sailboard
proa experiment kept to the una rig then it seems to me it's following pretty
much in the Minimum Proa ideas. The other that's come to mind is, of course, the
Jim Michalak Gizmo design.

--- In bolger@yahoogroups.com, "c.ruzer" <c.ruzer@...> wrote:

> Of course I'd like a Proa-60 one, yet I'm pro a 20 too!

This is really neat!   Go take a look at this thing. Of course they are
just finishing up the prototype If it works as advertises It will change
a lot of things.  I keep thinking about small transportation vehicles
and boats that can skim just over the ocean and set down an anchor.  I
have been arguing for a couple of years the merits of skin over frame
boats and of course getting poo-pooed .  Still they claim the material
is shrapnel and bullet resistant. So this may be the material I have
been yearning for? Have been arguing how is it we don't have a material
in these modern times that could be stretched over a frame and sail
across an ocean?? Saint Brendin sort of had one and it was called
leather and supposedly they sailed it across the Atlantic. This thing is
really interesting from a bating point of view and If I were younger I'd
pack up my junk and move out there and badger them until they gave me a
job :-)

http://www.aeroscraft.com/

FYI

eBay Item number: 370706165644

"This is an original magazine ad.  It measures 8 1/2 x 11 3/4. The ad is in good
condition" (1957? $6)

"Boats In The Cameras Eye

Two recent additions to the Chris-Craft line, a sport fisherman designed by
Philip Bolger, and a Mercury-powered Kayot pontoon (VW micro bus) share the
spotlight."

The caption to the Bolger design photo reads:

"Slic Chic" was designed by Philip Bolger, built by E. & H. Boat Works, Lake
Park, Fla. Twin 3 to 1 reduction Connell Cadillac Crusaders gives her a
sustained cruising speed of 20 knots.

Good one Bruce.

Here's another eBay display Bolger plan scan:

Vintage (for Jim Orrell)Sampan Express 19 semi-dory.
Item number: 121034770451 ($5)

Also there's:

A one page Yachting magazine article scan of a 44ft power cruiser 1965 built by
Mallorca Yacht & Boat Construction Assn, for the Med. Boat Review & Specs
Item number: 400346259803 ($6)

Different boats
Item number: 310503480366  ($67.97)

Bolger boats: Combining Small boats and The folding schooner, and other adventur
Plenty of primers on Bolger unified water flow theory in there, but fwiw no peas
- neither frozen nor seasoned nor seasof.
Item number: 321020901990  ($63.14)

I've no dog in those races - recently scored a signed FS though, but eBay are
attempting to extort extra profit from non-existant undisclosed at auction
"global shipping program" "import charges" by deception. Most probably I'll have
to sue the dogs and ACCC on them.






--- In bolger@yahoogroups.com, BruceHallman <hallman@...> wrote:
>
> Thanks, that is a new one to me.  >
>
> http://hallman.org/bolger/isometrics#Slic Chic

So now I am thinking to head back toward Bolger's construction scheme for
Fiddler 2 and adding the box keel on to it, with the 2x2 bottom timbers cutaway
over the walking area not under the berth.  The width of the box keel would be
to match the fore/aft keelsons that form the cabinetry.

I am thinking to clad the OUTSIDE of the hull (not the bottom), on the sides and
top, with 2" pink foam and wrap that with glass/resin, possibly over 1/8" ply
for fairing.  Anybody tried the foam this way?  I know PB&F suggested such a
scheme for one of the big ASxx cruisers. Insulation, floatation, and it gets the
water that much farther away from the structure.

Whatcha' think?

There was a guy who built some boats using a similar technique,
described in pretty good detail in the magazine Boatbuilder (used to be
published out of Florida, I think it is gone now). The builder called
it "quick and purty" construction.  He would glue foam on the outside
of a ply boat, then sculpt the foam into a nice rounded hull shape, and
sheath it in glass and epoxy.

Bob

> _______________________________________________________________________
> _
> 1a. Re: Fiddler 3 construction and foam insulation
>     Posted by: "daschultz8275@..."
> daschultz8275@... daschultz8275@...
>     Date: Sat Dec 15, 2012 11:03 am ((PST))
>
> So now I am thinking to head back toward Bolger's construction scheme
> for Fiddler 2 and adding the box keel on to it, with the 2x2 bottom
> timbers cutaway over the walking area not under the berth.  The width
> of the box keel would be to match the fore/aft keelsons that form the
> cabinetry.
>
> I am thinking to clad the OUTSIDE of the hull (not the bottom), on the
> sides and top, with 2" pink foam and wrap that with glass/resin,
> possibly over 1/8" ply for fairing.  Anybody tried the foam this way?
> I know PB&F suggested such a scheme for one of the big ASxx cruisers.
> Insulation, floatation, and it gets the water that much farther away
> from the structure.
>
> Whatcha' think?

----- Original Message -----

From: Bob Johnson

To: bolger@yahoogroups.com

Sent: Sunday, December 16, 2012 12:32 PM

Subject: [bolger] Re: Fiddler 3 construction and foam insulation

 

There was a guy who built some boats using a similar technique,
described in pretty good detail in the magazine Boatbuilder (used to be
published out of Florida, I think it is gone now). The builder called
it "quick and purty" construction. He would glue foam on the outside
of a ply boat, then sculpt the foam into a nice rounded hull shape, and
sheath it in glass and epoxy.

Bob

> __________________________________________________________
> _
> 1a. Re: Fiddler 3 construction and foam insulation
> Posted by: "daschultz8275@..."
> daschultz8275@... daschultz8275@...
> Date: Sat Dec 15, 2012 11:03 am ((PST))
>
> So now I am thinking to head back toward Bolger's construction scheme
> for Fiddler 2 and adding the box keel on to it, with the 2x2 bottom
> timbers cutaway over the walking area not under the berth. The width
> of the box keel would be to match the fore/aft keelsons that form the
> cabinetry.
>
> I am thinking to clad the OUTSIDE of the hull (not the bottom), on the
> sides and top, with 2" pink foam and wrap that with glass/resin,
> possibly over 1/8" ply for fairing. Anybody tried the foam this way?
> I know PB&F suggested such a scheme for one of the big ASxx cruisers.
> Insulation, floatation, and it gets the water that much farther away
> from the structure.
>
> Whatcha' think?

I don't like it, but it's more of a material complaint.

It doesn't matter if you build from the inside out, or the outside in - your
goal should be light weight skins, both stressed and well bonded. If you build a
boat with sufficient (stand-alone) interior skin strength, it doesn't make sense
to add adhesive, foam and a heavy second skin - you would be smarter and lighter
to insulate the interior.

The floatation is the same. (The argument to be able to fair the exterior skin
is ~OK, but there are a lot, lot better methods - like
Duflex.)

http://www.duflex.com.au/duflex2/products/strips

Still, unless you build a significant set of structural skins, your core will
get wet.

Of course, there are lots of cored boats (and planes), but none with styrofoam.
Have a look at Jamestowns cores:

http://www.jamestowndistributors.com/userportal/search_subCategory.do?categoryNa\
me=Core%20Materials%20and%20Foam&category=399&refine=1&page=GRID

All those foams and balsa have mechanical strengths 2-3 orders of magnitude
better than styrofoam - which essentially has none. Your skins will move, and
they do, your foam will fail in shear. You'll likely have a boat sitting in a
bucket. But, those materials are expensive.  Long and short of it, don't use
non-structural (weak) materials in a structural sandwich.

Having said that, I similar idea about building a dinghy from extruded styrfoam,
where you might waterjet the panels and shape the edges for a nice joint. But,
My idea was to cut holes every 6" or foot and insert a transverse wooden dowel,
balsa, or some rigid element to transfer shear across skins. You might estimate
the period knowing the properties from testing, but still, I think the skins
would delaminate eventually. I wouldn't risk it on a big project.

Gregg



--- In bolger@yahoogroups.com, "daschultz8275@..." <daschultz8275@...> wrote:
>
> So now I am thinking to head back toward Bolger's construction scheme for
Fiddler 2 and adding the box keel on to it, with the 2x2 bottom timbers cutaway
over the walking area not under the berth.  The width of the box keel would be
to match the fore/aft keelsons that form the cabinetry.
>
> I am thinking to clad the OUTSIDE of the hull (not the bottom), on the sides
and top, with 2" pink foam and wrap that with glass/resin, possibly over 1/8"
ply for fairing.  Anybody tried the foam this way?  I know PB&F suggested such a
scheme for one of the big ASxx cruisers. Insulation, floatation, and it gets the
water that much farther away from the structure.
>
> Whatcha' think?
>

----- Original Message -----

From: Gregory

To: bolger@yahoogroups.com

Sent: Sunday, December 16, 2012 2:46 PM

Subject: [bolger] Re: Fiddler 3 construction and foam insulation

 

I don't like it, but it's more of a material complaint.

It doesn't matter if you build from the inside out, or the outside in - your goal should be light weight skins, both stressed and well bonded. If you build a boat with sufficient (stand-alone) interior skin strength, it doesn't make sense to add adhesive, foam and a heavy second skin - you would be smarter and lighter to insulate the interior.

The floatation is the same. (The argument to be able to fair the exterior skin is ~OK, but there are a lot, lot better methods - like
Duflex.)

http://www.duflex.com.au/duflex2/products/strips

Still, unless you build a significant set of structural skins, your core will get wet.

Of course, there are lots of cored boats (and planes), but none with styrofoam. Have a look at Jamestowns cores:

http://www.jamestowndistributors.com/userportal/search_subCategory.do?categoryName=Core%20Materials%20and%20Foam&category=399&refine=1&page=GRID

All those foams and balsa have mechanical strengths 2-3 orders of magnitude better than styrofoam - which essentially has none. Your skins will move, and they do, your foam will fail in shear. You'll likely have a boat sitting in a bucket. But, those materials are expensive. Long and short of it, don't use non-structural (weak) materials in a structural sandwich.

Having said that, I similar idea about building a dinghy from extruded styrfoam, where you might waterjet the panels and shape the edges for a nice joint. But, My idea was to cut holes every 6" or foot and insert a transverse wooden dowel, balsa, or some rigid element to transfer shear across skins. You might estimate the period knowing the properties from testing, but still, I think the skins would delaminate eventually. I wouldn't risk it on a big project.

Gregg

--- In bolger@yahoogroups.com, "daschultz8275@..." <daschultz8275@...> wrote:
>
> So now I am thinking to head back toward Bolger's construction scheme for Fiddler 2 and adding the box keel on to it, with the 2x2 bottom timbers cutaway over the walking area not under the berth. The width of the box keel would be to match the fore/aft keelsons that form the cabinetry.
>
> I am thinking to clad the OUTSIDE of the hull (not the bottom), on the sides and top, with 2" pink foam and wrap that with glass/resin, possibly over 1/8" ply for fairing. Anybody tried the foam this way? I know PB&F suggested such a scheme for one of the big ASxx cruisers. Insulation, floatation, and it gets the water that much farther away from the structure.
>
> Whatcha' think?
>

----- Original Message -----

From: philbolger@...

To: bolger@yahoogroups.com

Sent: Sunday, December 16, 2012 3:02 PM

Subject: Re: [bolger] Re: Fiddler 3 construction and foam insulation

 

Regular home-center DOW blue-board has very low water absorption-rate if left afloat/wet.  As an inside-part of a laminate here, it would remain bone-dry !

Good thing that with a structure solid enough to live without the foam-belt, the outside addition of closed-cell blue foam-boards won't constitute any of the challenges quoted such as 'creep', water-absorption etc.  Ergo low-cost upgrade of the hull without serious drawbacks, as long as matters are well-bonded and glassed over. 

And any weight added via 1/8" skin in this case plus 'paper-weight' foam, plus glue/epoxy/glass will only add very modest weight on the trailer.  In the water however, the hull floats up some as it would have gained more buoyancy than net weight.  She could carry extra load before immersing to the same waterline as before...

Susanne Altenburger, PB&F

----- Original Message -----

From: Gregory

To: bolger@yahoogroups.com

Sent: Sunday, December 16, 2012 2:46 PM

Subject: [bolger] Re: Fiddler 3 construction and foam insulation

 

I don't like it, but it's more of a material complaint.

It doesn't matter if you build from the inside out, or the outside in - your goal should be light weight skins, both stressed and well bonded. If you build a boat with sufficient (stand-alone) interior skin strength, it doesn't make sense to add adhesive, foam and a heavy second skin - you would be smarter and lighter to insulate the interior.

The floatation is the same. (The argument to be able to fair the exterior skin is ~OK, but there are a lot, lot better methods - like
Duflex.)

http://www.duflex.com.au/duflex2/products/strips

Still, unless you build a significant set of structural skins, your core will get wet.

Of course, there are lots of cored boats (and planes), but none with styrofoam. Have a look at Jamestowns cores:

http://www.jamestowndistributors.com/userportal/search_subCategory.do?categoryName=Core%20Materials%20and%20Foam&category=399&refine=1&page=GRID

All those foams and balsa have mechanical strengths 2-3 orders of magnitude better than styrofoam - which essentially has none. Your skins will move, and they do, your foam will fail in shear. You'll likely have a boat sitting in a bucket. But, those materials are expensive. Long and short of it, don't use non-structural (weak) materials in a structural sandwich.

Having said that, I similar idea about building a dinghy from extruded styrfoam, where you might waterjet the panels and shape the edges for a nice joint. But, My idea was to cut holes every 6" or foot and insert a transverse wooden dowel, balsa, or some rigid element to transfer shear across skins. You might estimate the period knowing the properties from testing, but still, I think the skins would delaminate eventually. I wouldn't risk it on a big project.

Gregg

--- In bolger@yahoogroups.com, "daschultz8275@..." <daschultz8275@...> wrote:
>
> So now I am thinking to head back toward Bolger's construction scheme for Fiddler 2 and adding the box keel on to it, with the 2x2 bottom timbers cutaway over the walking area not under the berth. The width of the box keel would be to match the fore/aft keelsons that form the cabinetry.
>
> I am thinking to clad the OUTSIDE of the hull (not the bottom), on the sides and top, with 2" pink foam and wrap that with glass/resin, possibly over 1/8" ply for fairing. Anybody tried the foam this way? I know PB&F suggested such a scheme for one of the big ASxx cruisers. Insulation, floatation, and it gets the water that much farther away from the structure.
>
> Whatcha' think?
>

Cored boat hulls and decks get wet all the time, even when built to highest
possible standard. TPI invented SCRIMP infusion and we've all seen plenty or
Jboats, Freedoms, and other high-end, "scientifically" constructed cores fail.
Of course, epoxy accepts water slower than vinylester, which accepts water
slower than polyester, and many failures can be attributed to improperly made
penetrations, or just, penetrations. In nature, all voids are temporary.

And, I own a cored boat and built a cored airplane.

Dow Blue may not rot, but its glue lines will likely fail (right along its slick
surface). Wood rot happens quickest within a narrow range between totally dry
and soaking wet, but trapping water in a "closed" wood system is a bad idea.
It's at the core of the argument to encapsulate the interior or let it dry. Pick
your poison.

Balsa will rot, but it offers mechanical strength. Balsa is used end-grain;
meaning the fibers "T" against the skins, with a compressive strength of about
2000 psi.

http://www.gurit.cn/Files/Documents/Wind%20Energy%20Datasheets%20%28English%29/B\
alsaflex_WE_v3.pdf

Dow Formular High Compressive Strength Rigid Foam Insulation has a compression
strength of about 25-40 psi. Their failure criteria is interesting:

"Compressive resistance at yield or 10 %
"deformation, whichever occurs fi rst (with skins        40psi
"intact) min, psi (kPa)

http://commercial.owenscorning.com/products/foam/foamular-400/

http://commercial.owenscorning.com/assets/0/144/172/174/c18a63f8-2e4e-447b-97f3-\
3c8436223a20.pdf

So, if your survived rot and shear failure, imagine what's going to happen when
you sling your boat out, block it with stands, set it on trailer bunks, bump
against a piling, or even lean your shoulder against it in the boatyard. At
least outer skin will stop at the inner skin.

Seems like a lot of work to avoid insulating the interior ;-)

Gregg

http://www.yachtsurvey.com/core_materials.htm



--- In bolger@yahoogroups.com, <philbolger@...> wrote:
>
> Regular home-center DOW blue-board has very low water absorption-rate if left
afloat/wet.  As an inside-part of a laminate here, it would remain bone-dry !
>
> Good thing that with a structure solid enough to live without the foam-belt,
the outside addition of closed-cell blue foam-boards won't constitute any of the
challenges quoted such as 'creep', water-absorption etc.  Ergo low-cost upgrade
of the hull without serious drawbacks, as long as matters are well-bonded and
glassed over.
>
> And any weight added via 1/8" skin in this case plus 'paper-weight' foam, plus
glue/epoxy/glass will only add very modest weight on the trailer.  In the water
however, the hull floats up some as it would have gained more buoyancy than net
weight.  She could carry extra load before immersing to the same waterline as
before...
>
> Susanne Altenburger, PB&F
>   ----- Original Message -----
>   From: Gregory
>   To: bolger@yahoogroups.com
>   Sent: Sunday, December 16, 2012 2:46 PM
>   Subject: [bolger] Re: Fiddler 3 construction and foam insulation
>
>
>
>   I don't like it, but it's more of a material complaint.
>
>   It doesn't matter if you build from the inside out, or the outside in - your
goal should be light weight skins, both stressed and well bonded. If you build a
boat with sufficient (stand-alone) interior skin strength, it doesn't make sense
to add adhesive, foam and a heavy second skin - you would be smarter and lighter
to insulate the interior.
>
>   The floatation is the same. (The argument to be able to fair the exterior
skin is ~OK, but there are a lot, lot better methods - like
>   Duflex.)
>
>   http://www.duflex.com.au/duflex2/products/strips
>
>   Still, unless you build a significant set of structural skins, your core
will get wet.
>
>   Of course, there are lots of cored boats (and planes), but none with
styrofoam. Have a look at Jamestowns cores:
>
>  
http://www.jamestowndistributors.com/userportal/search_subCategory.do?categoryNa\
me=Core%20Materials%20and%20Foam&category=399&refine=1&page=GRID
>
>   All those foams and balsa have mechanical strengths 2-3 orders of magnitude
better than styrofoam - which essentially has none. Your skins will move, and
they do, your foam will fail in shear. You'll likely have a boat sitting in a
bucket. But, those materials are expensive. Long and short of it, don't use
non-structural (weak) materials in a structural sandwich.
>
>   Having said that, I similar idea about building a dinghy from extruded
styrfoam, where you might waterjet the panels and shape the edges for a nice
joint. But, My idea was to cut holes every 6" or foot and insert a transverse
wooden dowel, balsa, or some rigid element to transfer shear across skins. You
might estimate the period knowing the properties from testing, but still, I
think the skins would delaminate eventually. I wouldn't risk it on a big
project.
>
>   Gregg
>
>   --- In bolger@yahoogroups.com, "daschultz8275@" <daschultz8275@> wrote:
>   >
>   > So now I am thinking to head back toward Bolger's construction scheme for
Fiddler 2 and adding the box keel on to it, with the 2x2 bottom timbers cutaway
over the walking area not under the berth. The width of the box keel would be to
match the fore/aft keelsons that form the cabinetry.
>   >
>   > I am thinking to clad the OUTSIDE of the hull (not the bottom), on the
sides and top, with 2" pink foam and wrap that with glass/resin, possibly over
1/8" ply for fairing. Anybody tried the foam this way? I know PB&F suggested
such a scheme for one of the big ASxx cruisers. Insulation, floatation, and it
gets the water that much farther away from the structure.
>   >
>   > Whatcha' think?
>   >
>

----- Original Message -----

From: Gregory

To: bolger@yahoogroups.com

Sent: Monday, December 17, 2012 11:12 AM

Subject: [bolger] Re: Fiddler 3 construction and foam insulation

 

Cored boat hulls and decks get wet all the time, even when built to highest possible standard. TPI invented SCRIMP infusion and we've all seen plenty or Jboats, Freedoms, and other high-end, "scientifically" constructed cores fail. Of course, epoxy accepts water slower than vinylester, which accepts water slower than polyester, and many failures can be attributed to improperly made penetrations, or just, penetrations. In nature, all voids are temporary.

And, I own a cored boat and built a cored airplane.

Dow Blue may not rot, but its glue lines will likely fail (right along its slick surface). Wood rot happens quickest within a narrow range between totally dry and soaking wet, but trapping water in a "closed" wood system is a bad idea. It's at the core of the argument to encapsulate the interior or let it dry. Pick your poison.

Balsa will rot, but it offers mechanical strength. Balsa is used end-grain; meaning the fibers "T" against the skins, with a compressive strength of about 2000 psi.

http://www.gurit.cn/Files/Documents/Wind%20Energy%20Datasheets%20%28English%29/Balsaflex_WE_v3.pdf

Dow Formular High Compressive Strength Rigid Foam Insulation has a compression strength of about 25-40 psi. Their failure criteria is interesting:

"Compressive resistance at yield or 10 %
"deformation, whichever occurs fi rst (with skins 40psi
"intact) min, psi (kPa)

http://commercial.owenscorning.com/products/foam/foamular-400/

http://commercial.owenscorning.com/assets/0/144/172/174/c18a63f8-2e4e-447b-97f3-3c8436223a20.pdf

So, if your survived rot and shear failure, imagine what's going to happen when you sling your boat out, block it with stands, set it on trailer bunks, bump against a piling, or even lean your shoulder against it in the boatyard. At least outer skin will stop at the inner skin.

Seems like a lot of work to avoid insulating the interior ;-)

Gregg

http://www.yachtsurvey.com/core_materials.htm

--- In bolger@yahoogroups.com, <philbolger@...> wrote:
>
> Regular home-center DOW blue-board has very low water absorption-rate if left afloat/wet. As an inside-part of a laminate here, it would remain bone-dry !
>
> Good thing that with a structure solid enough to live without the foam-belt, the outside addition of closed-cell blue foam-boards won't constitute any of the challenges quoted such as 'creep', water-absorption etc. Ergo low-cost upgrade of the hull without serious drawbacks, as long as matters are well-bonded and glassed over.
>
> And any weight added via 1/8" skin in this case plus 'paper-weight' foam, plus glue/epoxy/glass will only add very modest weight on the trailer. In the water however, the hull floats up some as it would have gained more buoyancy than net weight. She could carry extra load before immersing to the same waterline as before...
>
> Susanne Altenburger, PB&F
> ----- Original Message -----
> From: Gregory
> To: bolger@yahoogroups.com
> Sent: Sunday, December 16, 2012 2:46 PM
> Subject: [bolger] Re: Fiddler 3 construction and foam insulation
>
>
>
> I don't like it, but it's more of a material complaint.
>
> It doesn't matter if you build from the inside out, or the outside in - your goal should be light weight skins, both stressed and well bonded. If you build a boat with sufficient (stand-alone) interior skin strength, it doesn't make sense to add adhesive, foam and a heavy second skin - you would be smarter and lighter to insulate the interior.
>
> The floatation is the same. (The argument to be able to fair the exterior skin is ~OK, but there are a lot, lot better methods - like
> Duflex.)
>
> http://www.duflex.com.au/duflex2/products/strips
>
> Still, unless you build a significant set of structural skins, your core will get wet.
>
> Of course, there are lots of cored boats (and planes), but none with styrofoam. Have a look at Jamestowns cores:
>
> http://www.jamestowndistributors.com/userportal/search_subCategory.do?categoryName=Core%20Materials%20and%20Foam&category=399&refine=1&page=GRID
>
> All those foams and balsa have mechanical strengths 2-3 orders of magnitude better than styrofoam - which essentially has none. Your skins will move, and they do, your foam will fail in shear. You'll likely have a boat sitting in a bucket. But, those materials are expensive. Long and short of it, don't use non-structural (weak) materials in a structural sandwich.
>
> Having said that, I similar idea about building a dinghy from extruded styrfoam, where you might waterjet the panels and shape the edges for a nice joint. But, My idea was to cut holes every 6" or foot and insert a transverse wooden dowel, balsa, or some rigid element to transfer shear across skins. You might estimate the period knowing the properties from testing, but still, I think the skins would delaminate eventually. I wouldn't risk it on a big project.
>
> Gregg
>
> --- In bolger@yahoogroups.com, "daschultz8275@" <daschultz8275@> wrote:
> >
> > So now I am thinking to head back toward Bolger's construction scheme for Fiddler 2 and adding the box keel on to it, with the 2x2 bottom timbers cutaway over the walking area not under the berth. The width of the box keel would be to match the fore/aft keelsons that form the cabinetry.
> >
> > I am thinking to clad the OUTSIDE of the hull (not the bottom), on the sides and top, with 2" pink foam and wrap that with glass/resin, possibly over 1/8" ply for fairing. Anybody tried the foam this way? I know PB&F suggested such a scheme for one of the big ASxx cruisers. Insulation, floatation, and it gets the water that much farther away from the structure.
> >
> > Whatcha' think?
> >
>

 

racing -funHello my fellow Bolger fans. I'm a total newbe to boats, and I don't even know the basic jargon yet. However, I would like to discuss the "big picture" with you.
For quite some time considered one day owning a  boat as a source of recreation. As world events are unfolding, I have started to think of a boat as a vehicle for evacuation and long-term survival.

The sailing scow, as depicted by Bolger's #501 and BWAOM Chapter 41, would seem to me to be a good choice. Cheaper to build, with lot's of space, and sufficiently seaworthy to serve as coastal cruisers. The flat bottom triloboat, Slacktide , is serving in this capacity up in South East Alaska. It is shoal draft and copper clad underneath, capable of grounding herself as the tides and weather require. An acceptable spot could turn into a long-term camping location.

However, the coastal cruising limitation is one that is disturbing to me. What if the wife insists on evacuating to Hawaii? Or the evacuation takes place when King Neptune is stirring up a fuss? Recently, I became aware of David Raison crossing the Atlantic in a minitransat 6.50, which is a 21-foot scow racing boat. I scratched my head on that one. I thought scows were not ocean crossers.

O.K., I know that Raison's 747 has the innovative "bulbous" bow, which, instead of cutting through the waves, bobs over them, using it's extra floatatriloboation to avoid plowing itself under. I also know the wide-bodied minitransats have dual rudders and a swing keel hanging on a gimbel, or something. Why could not a larger sailing he rcer probablyscow avail itself of features inspired by Teamwork Evolution and the minitransats? Of course, the scow I envision must retain it's extreme shoal draft, because neeping the boat, and going through tight shallow passages, is part of the survival strategy. Perhaps two advanced leaboards taking the place of the swing keel? Another attribute that can't be dispensed with is the metal covering on the bottom half of the hull, to allow beaching and neeping on rockier beaches.

Another issue is sails. What do you think of junk sails? Again, they are easier and cheaper to make, and I understand they are easy to repair at sea.
Here is a link to shoal draft boats, and a link to Teleport, a junk-rigged sailboat that took an Aussie, and his cute girlfriend, to the Arctic. My Boat Page 

Thanks for humoring me...I know my level of knowledge on these topics is comical.

Darrell
San Diego, CA