Glued carvel hull, anyone done this ?

[Scott Downey]

http://www.azom.com/details.asp?ArticleID=1116
Glued Carvel
Plank edges may be shaped and glued with a thickened epoxy mix or
alternatively the seams of dry fitted planks may be routed later to a
constant width and fitted with wooden splines which are glued into place.
This latter method is the usual treatment when a traditionally built carvel
craft is reconstructed using epoxy adhesives as part of a full restoration
program. Sometimes a thickened epoxy mix is introduced into the seams as an
alternative to wooden splines and this seems to be just as effective in
fastening the plank edges together. The planking is also glued to the spine
and framework, which on new boats is built of laminated hardwood, glued and
coated with epoxy.

[Steve]

If you glue the seams on a carvel planked hull, it is now longer a carvel
hull.. More like a stripped plank hull..

A carvel hull is built to allow the panks to expand and contract and for the
hull to twist with out opening a seam..

I have recaulked hulls that had been on the hard too long and the planking
was dry.. Being carefull not to drive the cotton too tight or it could cause
the plank to pull it's fastenings. Even if I only put in enough seam filler
to bring the seam flush with the planking surface, once the hull swelled the
excess filler would squeeze out 3/16" and would later have to be smoothed
down again.

If you want to glue the seams, select a strip planked design..

[Brian D]

Hey Scott,

Are you planning on fairing away the seams? If so, then glued-carvel
would be fine ...not a lot different from strip-building, except for the
mention of a splined joint between the planks. If you are not going to
fair-away the seams, then it seems to me that the finish work will be
harder. With epoxy, you must really seal 100% of the wood, on all sides.
Epoxy's great stuff, but it also holds water at the epoxy/wood interface.
Hence the reason for a complete seal and then keeping it that way. I think
a fellow should either commit to a 100% seal on all sides, or forget epoxy
completely. My 2-bits. You might also check with Al Gunther, who frequents
r.b.b.. I can't remember for sure, but I think he's doing glued-carvel.
Or, I should say that he's building a 26' carvel-planked sailboat and when I
needed it, he had a lot of very good advice on the use of epoxy. Might try
a search on "Al's 26" and see what you find.

Brian

Post by Scott Downey
http://www.azom.com/details.asp?ArticleID=1116
Glued Carvel
Plank edges may be shaped and glued with a thickened epoxy mix or
alternatively the seams of dry fitted planks may be routed later to a
constant width and fitted with wooden splines which are glued into place.
This latter method is the usual treatment when a traditionally built carvel
craft is reconstructed using epoxy adhesives as part of a full restoration
program. Sometimes a thickened epoxy mix is introduced into the seams as an
alternative to wooden splines and this seems to be just as effective in
fastening the plank edges together. The planking is also glued to the spine
and framework, which on new boats is built of laminated hardwood, glued and
coated with epoxy.

[Jacques Mertens]

Good method.
Ideally you should fiberglass the hull outside for extra protection.
While you are at it, fiberglass the inside too, it will increase strength
tremendously.
If you use biaxial glass, it will become a true sandwich.
Note that you don't really need to start with wood, you could us foam
strips, that would be even better.
Oops, we just got ourself a real nice composite boat . . .

--
Jacques
http://www.bateau.com

Post by Scott Downey
http://www.azom.com/details.asp?ArticleID=1116
Glued Carvel
Plank edges may be shaped and glued with a thickened epoxy mix or
alternatively the seams of dry fitted planks may be routed later to a
constant width and fitted with wooden splines which are glued into place.
This latter method is the usual treatment when a traditionally built carvel
craft is reconstructed using epoxy adhesives as part of a full restoration
program. Sometimes a thickened epoxy mix is introduced into the seams as an
alternative to wooden splines and this seems to be just as effective in
fastening the plank edges together. The planking is also glued to the spine
and framework, which on new boats is built of laminated hardwood, glued and
coated with epoxy.

[Stephen Baker]

Post by Jacques Mertens
Oops, we just got ourself a real nice composite boat . . .

Sarcasm ill becomes you, Jacques....

;-)

[Jim Conlin]

However, if the planking cannot be fully encapsulated, meaning kept DRY, then
i'd hesitate to fill seams with something firm like splines or epoxy putty. If
the planking gets wet and tries to expand, something has to give. It might be
frames or fastenings.
Only if the planking is of a species that doesn't swell much, might you get away
with this.

Post by Jacques Mertens
Good method.
Ideally you should fiberglass the hull outside for extra protection.
While you are at it, fiberglass the inside too, it will increase strength
tremendously.
If you use biaxial glass, it will become a true sandwich.
Note that you don't really need to start with wood, you could us foam
strips, that would be even better.
Oops, we just got ourself a real nice composite boat . . .
--
Jacques
http://www.bateau.com

Post by Scott Downey
http://www.azom.com/details.asp?ArticleID=1116
Glued Carvel
Plank edges may be shaped and glued with a thickened epoxy mix or
alternatively the seams of dry fitted planks may be routed later to a
constant width and fitted with wooden splines which are glued into place.
This latter method is the usual treatment when a traditionally built

carvel

Post by Scott Downey
craft is reconstructed using epoxy adhesives as part of a full restoration
program. Sometimes a thickened epoxy mix is introduced into the seams as

an

Post by Scott Downey
alternative to wooden splines and this seems to be just as effective in
fastening the plank edges together. The planking is also glued to the

spine

Post by Scott Downey
and framework, which on new boats is built of laminated hardwood, glued

and

Post by Scott Downey
coated with epoxy.

[Jacques Mertens]

Correct: hybrid solutions could cause problems.
I share your doubts about glued seams. There are some epoxies that are
sufficiently flexible but why take a chance?
Either build her as wooden boat or as a composite (fiberglassed boat).

--
Jacques
http://www.bateau.com

Post by Jim Conlin
However, if the planking cannot be fully encapsulated, meaning kept DRY, then
i'd hesitate to fill seams with something firm like splines or epoxy putty. If
the planking gets wet and tries to expand, something has to give. It might be
frames or fastenings.
Only if the planking is of a species that doesn't swell much, might you get away
with this.

[Rufus]

I heard that some Scandinavian builders built carvel boats with no gap
at all, just perfect seams, no glue, no caulking. Don't know details,
it's been a while since I looked into it. I believe they were sailing
vessels, 35' and more, they were built thus to provide more hull
stiffness, amoung other things, and they didn't seap/leak at all.

Sorry, can't recall how/where I found the info. But it means there's
more than one way to skin a cat...

Here's an interesting post I found while doing a quick search to see if
I could find any more info:
http://www.rtpnet.org/robroy/baidarka/1997/Nov/0020.html

Search "no caulking" on this page:
http://www.mastmate.com/a-f.html

Another mention:
http://personal.riverusers.com/~emkay/building2.html

Well, I haven't found the references I wanted, but that's it for now.

Rufus

Post by Jacques Mertens
Correct: hybrid solutions could cause problems.
I share your doubts about glued seams. There are some epoxies that are
sufficiently flexible but why take a chance?
Either build her as wooden boat or as a composite (fiberglassed boat).
--
Jacques
http://www.bateau.com

Post by Jim Conlin
However, if the planking cannot be fully encapsulated, meaning kept DRY,

then

Post by Jim Conlin
i'd hesitate to fill seams with something firm like splines or epoxy

putty. If

Post by Jim Conlin
the planking gets wet and tries to expand, something has to give. It

might be

Post by Jim Conlin
frames or fastenings.
Only if the planking is of a species that doesn't swell much, might you

get away

Post by Jim Conlin
with this.

[P.C.]

Hi

Post by Rufus
I heard that some Scandinavian builders built carvel boats with no gap
at all, just perfect seams, no glue, no caulking. Don't know details,
it's been a while since I looked into it. I believe they were sailing
vessels, 35' and more, they were built thus to provide more hull
stiffness, amoung other things, and they didn't seap/leak at all.

Snip

Sure you need no caulking if you don't want any, ------ this was common
knowleage and there are a number of tricks to make sure the seam work tight
without caulking ;
Hammer down a long rod along the plank edge and plane away untill you reach
the bottom of the grove made by deforming the plank edge. Then when soaked
the compressed wood will swell.
Place the planking forgetting about the seam ,as long as the seam is not
wider than a router bit, when you are sure the wood stabilised router away
along the seam and glue in a wood spline.
Still these old tricks work for true wooden boats ,Im'e not sure it's worth
the efford with any ply boat, even if a routered in wood spline along a
tortured seam is there from the start within the plans ,it's proberly a very
good idea but I wonder if any box boat plans ask this, ------ case so I
would like to se the naval architect recomend from his own hands-on
experience.

P.C.
Loading Image...

[William R. Watt]

Phil Bolger once started builing a hull that way but gave it up when he
found out how much the adhesive was costing, and finished it the old
fashioned way. You might want to cost out the project before getting started.

There are more flexible adhesives than epoxy. You might look into some of
them. I've heard of polyurethane being used on lapped strake (cliker) hulls.

Seams above the waterline tend to dry out and open up while seams below
the waterline swell up tight. If glued seams can't open as the wood dries
the wood may split. TF Jones encoutered this after 10 years on a lapped
strake canoe built light with thin strakes. That canoe was kept inside out
of the sun when not in use.

Post by Scott Downey
http://www.azom.com/details.asp?ArticleID=1116
Glued Carvel
Plank edges may be shaped and glued with a thickened epoxy mix or
alternatively the seams of dry fitted planks may be routed later to a
constant width and fitted with wooden splines which are glued into place.
This latter method is the usual treatment when a traditionally built carvel
craft is reconstructed using epoxy adhesives as part of a full restoration
program. Sometimes a thickened epoxy mix is introduced into the seams as an
alternative to wooden splines and this seems to be just as effective in
fastening the plank edges together. The planking is also glued to the spine
and framework, which on new boats is built of laminated hardwood, glued and
coated with epoxy.

--

[Scott Downey]

I was thinking if the planks were dry and shrunk then further drying wont
cause any splitting
The only pressure will be when the planks absorb water, now the planks are
under pressure anyway when wet, this is what seals the seams. I assume when
the boat was built, the inner plank edges were touching, the outer edges
were angled away so you can put in caulking.
I know a lot of you dont like the idea of planks pressuring each other but
is not this what happens anyway when they soak up water sealing the hull in
a conventional design?
People think something has to give if the edges are joined but are many
just making assumptions about this with no real experience.

Post by William R. Watt
Phil Bolger once started builing a hull that way but gave it up when he
found out how much the adhesive was costing, and finished it the old
fashioned way. You might want to cost out the project before getting started.
There are more flexible adhesives than epoxy. You might look into some of
them. I've heard of polyurethane being used on lapped strake (cliker) hulls.
Seams above the waterline tend to dry out and open up while seams below
the waterline swell up tight. If glued seams can't open as the wood dries
the wood may split. TF Jones encoutered this after 10 years on a lapped
strake canoe built light with thin strakes. That canoe was kept inside out
of the sun when not in use.

Post by Scott Downey
http://www.azom.com/details.asp?ArticleID=1116
Glued Carvel
Plank edges may be shaped and glued with a thickened epoxy mix or
alternatively the seams of dry fitted planks may be routed later to a
constant width and fitted with wooden splines which are glued into place.
This latter method is the usual treatment when a traditionally built carvel
craft is reconstructed using epoxy adhesives as part of a full restoration
program. Sometimes a thickened epoxy mix is introduced into the seams as an
alternative to wooden splines and this seems to be just as effective in
fastening the plank edges together. The planking is also glued to the spine
and framework, which on new boats is built of laminated hardwood, glued and
coated with epoxy.

--
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Post by William R. Watt
William R Watt National Capital FreeNet Ottawa's free community

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Post by William R. Watt
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[Meindert Sprang]

Post by Scott Downey
I know a lot of you dont like the idea of planks pressuring each other but
is not this what happens anyway when they soak up water sealing the hull in
a conventional design?

Yes. But in a conventional carvel hull, the caulking absorbs the extra
dimension of the expanding wood. When you glue is with epoxy, nothing is
left to absorm the expansion and the planks will eventually burst off the
ribs. The reason red cedar is used for stripplanking is because it is a soft
wood and therefore producing less pressure when it swells. Quite a few
builders, Paul Gartside is one of them, even state that layers of glass on a
larger stripplanked hull are not strong enough and they advise to cover the
strips with diagonal layer(s) of plywood first. I have also seen an oak hull
built this way; bead an cove strippplanked, covered by two layers of ply and
finished with for-and-aft running planks to add extra body and give it the
traditional look of carvel.

Meindert

[P.C.]

Hi

Post by Meindert Sprang
Yes. But in a conventional carvel hull, the caulking absorbs the extra
dimension of the expanding wood.

WHAT ?????

Don't anyone in this forum have any hands-on experience ?
Caulking is done at the outher third of the seam and the seam is prepared
for caulking, ------- It's bloddy _not_ the damned caulking that make the
hull watertight when you build a cravel planked boat, as the bloody seams
are TIGHT even before the caulking is there.
Do you realy think cravel build boats are just a bunch of planks with seems
inbetween that you look right thru , and that you just forget about the
craftmanship as you just Bang in caulking ???
Well that's _not_ how you build a cravel planked boat hull ------- and be
glad for that, as if this was how, no craftmanship or respect for the crafts
would survive the sailers counting on boatbuilders having the knowleage to
make a safe vessel.
Just becaurse you as amature builder, seen an old mistreated hull, with
inverts opened seams, do damn'ed not mean that this sort of bad
craftmanship, was what made these beautifull vessels ------ all it mean is,
that some ignorant Amature been doing a temp. repair, where a profesional
would have replaced the plank. ( nice case you trust your life upon ).

Bet you even think that caulking is just about banging in stuffing untill
the whole plank is forced to destroy the seams around and above, ------ seem
like you even mix two compleatly different technikes by talking about
caulking with Lapstrake building ; YOU DO NOT CAULK A LAPSTRAKE HULL, unless
it's old and worn , unless the planks shuld have been replaced decades ago,
don't you Amature boatbuilders know the difference between Lapstrake and
Cravel ; then how the hell can you avoid to crack the plank edge if you
start caulking a Lapstrake hull -------- don't you se it, don't you even
know that you can destroy a lapstrake hull by caulking it ????

P.C.

[Meindert Sprang]

Post by P.C.
Hi

Post by Meindert Sprang
Yes. But in a conventional carvel hull, the caulking absorbs the extra
dimension of the expanding wood.

WHAT ?????

It is my understanding that a carvel hull has a slight bevel on each plank,
so the planks only touch at the inside of the hull. The cotton used for
caulking is then driven about halfway in the seam, in order to form a sort
of watertight 'rope' slightly indenting the planksides.

Post by P.C.
Don't anyone in this forum have any hands-on experience ?
Caulking is done at the outher third of the seam and the seam is prepared
for caulking, ------- It's bloddy _not_ the damned caulking that make the
hull watertight when you build a cravel planked boat, as the bloody seams
are TIGHT even before the caulking is there.

Mmmm, I quote from the Boatbuilding Manual from Robert Steward:
"Carvel planking is usually made with the seams tight on the inside and open
on the outside to receive the cotton caulking, which makes the planking
watertight".

Post by P.C.
Bet you even think that caulking is just about banging in stuffing untill
the whole plank is forced to destroy the seams around and above, ------ seem
like you even mix two compleatly different technikes by talking about
caulking with Lapstrake building ; YOU DO NOT CAULK A LAPSTRAKE HULL, unless
it's old and worn , unless the planks shuld have been replaced decades ago,

Ehhrr, where exaclty was I referring to lapstake construction?

Post by P.C.
don't you Amature boatbuilders know the difference between Lapstrake and
Cravel ; then how the hell can you avoid to crack the plank edge if you
start caulking a Lapstrake hull -------- don't you se it, don't you even
know that you can destroy a lapstrake hull by caulking it ????

Well, at a boatbuilding school here in the Netherlands they build clinker
lapstrake hulls and they do put sikaflex between the strakes for caulking.
Nothing is destroyed by that.

Geez Per, why on earth ary you reacting so offensive????

Meindert

[Steve]

Post by Scott Downey
the boat was built, the inner plank edges were touching, the outer edges
were angled away so you can put in caulking.

Plank edges do not normally touch there is a gap that will allow for the
ultimate swelling or expansion of the plank. If the caulking cotton is
driven to tight (or you fill the seam with glue or epoxy) the plank will
'pull it's fastenings". The expanding plank has to go someplace.

[William R. Watt]

wood is somewhat compressable so the thin edge will compress. however it
could also deform so when the wood dries out again the gap is larger.

it was common for boat hauled out over the winter to leak when first put
back in the water in the spring because the wood (and calking) had dried
out and opened over the winter. the boat would be left in shallow water to
soak up tight and stop leaking. it would them be bailed out and used for
the season.

there is an antique boat club near here which uses pumps in the spring to
keep the boats from sinking while they are soaking up.

Post by Steve

Post by Scott Downey
the boat was built, the inner plank edges were touching, the outer edges
were angled away so you can put in caulking.

Plank edges do not normally touch there is a gap that will allow for the
ultimate swelling or expansion of the plank. If the caulking cotton is
driven to tight (or you fill the seam with glue or epoxy) the plank will
'pull it's fastenings". The expanding plank has to go someplace.
--
My opinion and experience. FWIW
Steve
s/v Good Intentions

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