I will be replacing the entire plywood interior and deck of a 38 foot
fiberglass sloop starting this summer. I plan to use coosa composite panels
epoxied to the fiberglass hull. I am planning a few minor changes, I may
extend the cockpit aft to the transom and I would like to install pipe
berths. This sailboat will be used mostly offshore, 15 years of Newport to
Bermuda races, then I plan on a solo circumnavigation. I know that most of
you are shaking your heads ruefully thinking "another future failure" and I
have to acknowledge that that is a possibility. Let me give you my resume.
As a teenager, I built an 8 foot hydroplane. In my twenties I built a SCCA
race car and my house. In my thirties and forties I built a couple of
businesses and a small airplane. During the last 5 years I doubled the size
of my house. Also, my father built this boat during the 1980's.
I have a million questions for you all let me start with these:
Should I have an intimate fit between the bulkheads and hull or would a gap
for epoxy be preferable? Or maybe the center of the panel should in contact
with a wedge shaped space fore and aft of the joint for epoxy.
The deck was bolted down with bedding compound. Why can't this be a epoxied
joint? Or even West's G-flex?
I have never done vacuum bagging. Looks complicated, should I find someone
to help me with it the first time? Any recommendations for help in the
Annapolis area?
Also, I use a refrigerator type vacuum pump in my business. Would this be
adequate?
I have some old kevlar sails around, can I cut strips of them and use these
for the tabbing?

Thanks in advance

On Thu, 20 May 2010 20:47:36 -0500, Richard Geis
rmgeisatverizondotnet wrote:

I will be replacing the entire plywood interior and deck of a 38 foot
fiberglass sloop starting this summer. I plan to use coosa composite panels
epoxied to the fiberglass hull. I am planning a few minor changes, I may


I am assuming that you are intent on building a light weight cruiser
racer. If so, you might consider using the Coosa for structural
bulkheads and foam for the non-structural. I have never seen "coosa
composite panels" but googled on it and it looks as though it would be
considerably heavier then glass sheathed foam..

Of course, cost is always a consideration and if you consider the
added work, sheathed foam is probably more costly but it certainly is
a whole lot lighter.

Depending on your hull construction you can cut the panels to shape
and glue them in and tab them. I like to use a bit of high strength
filler to fair a small radius between the panel and the hull and then
run the tape over that. However others tab it in and then fair it with
softer, sanding filler.

extend the cockpit aft to the transom and I would like to install pipe
berths. This sailboat will be used mostly offshore,

Pipe berths are not that comfortable :-)

It is one thing to sail for a specific length of time on a stripped
down racer, a liter of water a day, and weigh the bags before you
bring them aboard... but we'll be off this friggin thing in a week and
then boys I'm going to have a bath.

It is quite another to set off on a voyage where you will be spending
months, perhaps, confined to the boat. and even worse if you have a
woman with you - most of them can use more fresh water then a herd of
elephants.

15 years of Newport to
Bermuda races, then I plan on a solo circumnavigation. I know that most of

If you anticipate doing any long distance cruising you really do want
to think about storage. Until you live on a boat for a while you can't
imagine how much stuff you will be carrying.

you are shaking your heads ruefully thinking "another future failure" and I
have to acknowledge that that is a possibility. Let me give you my resume.
As a teenager, I built an 8 foot hydroplane. In my twenties I built a SCCA
race car and my house. In my thirties and forties I built a couple of
businesses and a small airplane. During the last 5 years I doubled the size
of my house. Also, my father built this boat during the 1980's.
I have a million questions for you all let me start with these:

Should I have an intimate fit between the bulkheads and hull or would a gap
for epoxy be preferable? Or maybe the center of the panel should in contact
with a wedge shaped space fore and aft of the joint for epoxy.
The deck was bolted down with bedding compound. Why can't this be a epoxied
joint? Or even West's G-flex?

Depending on how stiff the hull is you may want to use a thin layer of
foam between the bulkheads and the hull to avoid a "hard spot". On the
other hand if the hull is pretty stiff then just fit the bulkhead
right up to the hull.

Most modern boats are made with a separate deck structure that is
bolted/screwed to the hull but older boats had the deck structure
bonded into the hull, which probably resulted in a much stiffer hull..
I have never done vacuum bagging. Looks complicated, should I find
someone
to help me with it the first time? Any recommendations for help in the
Annapolis area?
Also, I use a refrigerator type vacuum pump in my business. Would this be
adequate?

There are innumerable sites on the Web that can teach you the
rudiments of vacuum bagging. Read up on it and then make some practice
pieces. You can use almost anything that sucks a vacuum. Air
conditioning pumps are probably overkill but they certainly work -
used mine several times.

But do put a trap in the line to keep the pump from ingesting epoxy if
you got too free with the resin :-)

I have some old kevlar sails around, can I cut strips of them and use these
for the tabbing?

I would use glass. Perhaps because I haven't used a lot of kevlar and
don't know quite what to expect, but on the other hand, the glass
will be strong enough.

If you do use old sails make a few test joints and break them. You may
have discovered the secret of the century, or maybe it won't work :-(

Thanks in advance

Cheers,

Bruce
(bruceinbangkokatgmaildotcom)

On Thu, 20 May 2010 20:47:36 -0500, Richard Geis
rmgeisatverizondotnet wrote:

I have some old kevlar sails around, can I cut strips of them and use these
for the tabbing?

Laminating kevlar is quite different from sail making kevlar, and the
kevlar sails are probably faced with myar which will not wet out or
bond with epoxy.

Sorry for the late reply.
I am with Bruce when he writes about bedding with epoxy putty
and then taping with glass weave. Orient fibers +/- 45 degrees.

Scroll down to the middle of this page for some photos of
interior parts bedded to hulls:
http://hem.bredband.net/b262106/Boat/build.html

Later I learned a neat trick from Danish designer Lars Oudrup:
Fixate parts to be bonded using heat glue. You don't need much
since it is only there to keep things in position while you
apply the epoxy putty and while it cures.

/Martin