Finally here is a site giving you a choice of manufacturers

http://buy.ecplaza.net/search/1s1nf20sell/fiberglass_beams.html

Strip planking can be done with using an expanding polyurethane glue
to stick the strips together and then sanding smooth, bogging, sanding
smooth again and putting on a fibreglass skin. Marginally heavier than
foam plus glass as it is a denser core but needs less glass. The
beauty of the table finish is the minimal use of bog which can
significantly affect weight. The longitudinal stiffness is not needed
so much in the ww hull so a little more weight can be saved there.
Bulkheads are definitely needed at the mast position(s) and so is
reinforcing of the hulls in that area. The beauty of sailing loads
being so concentrated in the lw hull, is that the big openings for the
main accommodation are well clear. It is amazing how much stress can
be concentrated around a hatch opening. I calculated that there is
much more weight in the extra support needed for a hatch than the
equivalent skin without the hatch, and you still have the extra weight
of the hatch. If a hatch area is subjected to sailing loads, then this
is a nightmare. Consider the torque on the structure in a swell if one
mast ws taking most of the load and the opposite ww bow was in the air
on top of a wave. The unstayed rig means that the sailing loads are
concentrated between the crossbeams, though there is some load on the
lw bow as it supplies some of the leeway resistance.
In my interpretation, a flare on the inside complicates things a
little but is supported by bunks and shelving (adding at least a
hundred pounds, but partly off set by increased bury for the
crossbeams and ruddershafts) It is not just the surface area but also
the extra weight of joining material ie hand layed glass with
attendant bog.this can add 15-20% to the internal furniture

Away from the main sailing loads, the need for bulkheads is less,
depending on the skin structure. The thicker the skin, the less
bulkheads needed. Much of the stiffening can be incorporated into the
structure through the furnishings. Shelves, cupboards, tanks, bunks
forward in the ww hull ends, ablution structures, steps, bouyancy
compartments
I can't give you accurately the weights of the crossbeams and rudders
but they definitely weren't 'tuckable under the arm and walk of'
weight. They have to support a cantilever of about a couple of tonnes
at a distant of about 5m. This is a serious piece of engineering. The
crossbeams would have to weigh at least in the order of a couple of
hundred kg a piece plus at least another 40kg for the rudder supports,
and the rudder blades from what I remember on Rare Bird were just
possible for one person to lift, maybe in the order of 60-100kg.
Transom hung rudders need to include the shaft which won't be light.
In aluminium or stainless in the order of 50 to 100kg each.

I think we have found about 2000lbs. Consider that Blind date came in
at less than 2 tonnes before rig. Once you increase the accommodation
weight, you need to increase the strength right through, hence the
increase to Rare Bird

--- In harryproa@yahoogrou ps.com.au, "Gardner Pomper" <gardner@... > wrote:
>
> From what I understand of strip planking, you need to coat all 4
sides of
> each strip with resin. Isn't that alot heavier than just using a
> foam/honeycomb core? Or do you reduce the weight of fiberglass to
make up
> for that?
> Any idea what the weights of the crossbeams are for Rare Bird ?
>
> So, I might be fairly close on the structure, but just leaving out
weights
> of extra things like hatches, cleat backing plates, hardpoints and
stuff?
>
> My feeling on bulkheads was that around the mast, the crosssection
of the
> lee hull is 8' h x 2' w. Two bulkheads on each side of the mast, and the
> equivalent of 1 more crosswise would be an extra 100 sq ft (or 100 lbs).
> Needs to be accounted for, but does not take up the greater part of the
> 3-4000 pounds I suspect I am missing.
>
> - Gardner
>
> On Wed, Jan 7, 2009 at 9:14 PM, Robert <cateran1949@ ...> wrote:
>
> > There are a suprising amount of panels needed for interior
separation,
> > such as bulkheads, storage areas, bouyancy compartments, cupboards,
> > shelving. Rare Bird was strip planked so would have to include a bit
> > of bog. Rare Bird also has a dinghy ramp. The crossbeams and rudders
> > need to be pretty substantial as do the reinforcing to transfer the
> > loads between them and the rig There is also the weight of hatches.
> > Rare Bird weight should be pretty close if you can keep the bogging
> > down to a minimum.Blind date is a fair bit lighter.
> > Your calculations of area seem just a little more than an extended
> > Harry 15m/9m that I have been trying to design so we are making
> > similar mistakes -- In
harryproa@yahoogrou ps.com.au<harryproa%40yahoog roups.com. au>,
> > "Gardner Pomper"
> >
> > <gardner@> wrote:
> > >
> > > Hi,
> > > I have been spending way too much time researching materials online,
> > but the
> > > end result is that I am again confused on how to estimate the weight
> > of a 50
> > > ft cruising harryproa. I have gone through and added up the hull,
> > bulkheads,
> > > furniture, hardtop, cockpit, bunks, etc, etc and come up with 2100
> > sq ft.
> > > This does not include the rig, crossbeams or rudders, since I don't
> > know how
> > > to calc that.
> > >
> > > Anyway, I then research the core material (pretty much all of
them are
> > > 80Kg/m3), which translates to 0.3 lbs/sq ft for 2/4" (20mm) core.
> > Add in 2
> > > layers of 18 oz/yd2 fiberglass (1 top and 1 bottom) and an equal
> > weight of
> > > resin and I get 0.8 lbs/sq ft total. Add 20% for fillets, bog, etc,
> > and it
> > > comes out pretty much exactly 1 lb/sq ft.
> > >
> > > I add in my batteries, outboard engines, refrigeration, water
and fuel
> > > tanks, instrumentation, ground tackle, etc and get another 1500 lbs.
> > >
> > > With schooner rig, I would estimate each mast/sail/boom combo at
> > about 500
> > > lbs, so that is 1000 for the rig.
> > >
> > > I am now up to 2100 lbs for structure + 1500 lbs equipment + 1000
> > lbs rig =
> > > 4600 pounds.. supposedly only missing the crossbeams and rudders.
> > >
> > > I am happy with that. But then the urge to do a reality check comes
> > in and I
> > > look at Rare Bird at 6,720 lbs, and it doesn't have a 10' x 12'
> > bridgedeck.
> > >
> > > So, what am I doing wrong? At about 5000 lbs and 1000 sq ft of sail,
> > this
> > > should be a screamer, but if it is 10,000 lbs with the same sail
> > area, that
> > > is a totally different boat!
> > >
> > > I would probably be safe by just taking Rare Bird and adding a
couple
> > > thousand pounds, but I actually want to be able to do this
stuff. Help!
> > >
> > > Thanks,
> > >
> > > - Gardner Pomper
> > > York, PA
> > >
> >
> >
> >
>