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Glued
Joints on Sitka Spars
The glued joints on the
sitka spars on Cheoy Lees are a concern. I have read several accounts from members
of these glued joints failing. The question is should we try to separate
the joints
and reglue. Perhaps the decision would be based on how well the spars were
maintained over the years with good varnish...
From: |
James
McGarvey |
Posted: |
12/19/98
3:49 PM |
Comments
I have read that the glued joints can and have failed on older masts. Have read that if
glue is dark this is sign of aging and weakness. Question, are not some glues dark to
begin with?? Also I do not want to take masts apart and reglue - thinking of drilling and
placing screws every 6-10 inches. Anyone with any thoughts on this??
Re: Glued Joints on Sitka Spars
From: Chave
Date: 7/24/98
Time: 8:35:22 PM
James,
I too have noticed that some glues
are dark, and the fillers which I have added to glues have darkened them. So I would not
be worried about darkened glues. It might worry me a little if the glued joint was
unevenly darkened, and then I would seek a reason such as moisture in the joint.
I think that the first thing I would do if I was worried about a glued joint in a mast is
to take a good look at the joint under magnification of some kind.
If I saw any signs of separation along a seam, I would be tempted to strip the varnish off
of the seam to take a closer look. I would also be inclined to put the mast on two saw
horses and load the mast in the middle to see if the resulting bend affected the suspect
joint. I would load the joint so that the suspect region was on the outer radius of the
bend resulting from the load, so that this part of the joint saw the greatest tensile
strain.
Lastly I would be disinclined to put screws into a glued joint on a mast. Screws cause a
point load local to their insertion, whereas a glued joint carries the load over a broad
region. I think that the screws will not be satisfactory ever. The will tend to leak water
into the joint, and they will tend to loosen as the mast flexes.
I think that there is no substitute for cutting open a bad scarf joint, with a sharp cross
cut saw, sanding the faying surfaces flat and true, and re-glueing it.
best, robert
From: Rusty
Date: 7/29/98
Time: 8:13:03 PM
Remote Name: 137.79.152.139
Comments
I have a Robb 35 and hace had two chances to deal with the boom. The boom is a four piece
Sitka Spruce and had delamed in some places, due to a hard jib. The repair held when
stress tested by my two young children
during climbing trials during a three year live
aboard. When I hauled for repairs the first reglu had held but she had delamed in other
spots. I chose to carefully hand saw the seams ( will discuss) cleaned and re glued with
Resorcinal, binding with inner tubes over wax paper. The glue is dark and the job appears
to be a good fix. Please write to discuss. Good luck..
From: Bob Cleek - Vertue: Patience
Date: 8/15/98
Time: 2:14:40 PM
Remote Name: 208.255.138.237
Comments
Nothing wrong with Cheoy Lee spar glue, except age and technological limitations of the
time. Yes, the "monkey poop" they used to hold them together breaks down, just
like that awful red lead and old paint they used for bedding compound in the 1960's! I
would not take a saw to the glue lines if it can be avoided. I have completely
disassembled my mast and boom down to the individual scarfs, so I been there, done that
and got the tee shirt! The good news is that the stuff doesn't hold that tight, so I used
hardwood wedges which I drove between the seams VERY carefully and gradually until I
popped them all apart. Then I cleaned off all the old adhesive and planed them fair. I
soaked the entire think in Smith's penetrating epoxy and then reassembled using WEST
system epoxy. Laid ten coats of varnish just so on top of it all. Has held perfectly for
ten years now! Go for it!
Fatigued Mast Brackets, Failure & Replac
From: Chave
Date: 7/24/98
Time: 5:30:48 PM
Comments
I recently refurbished my mast with new varnish, new halyards and the like. The standing
rigging including the mast head bracket, and the port spreader bracket were new, replaced
by the previous owner. Everything else was original seemed good under careful visual (but
no dye penetrant) inspection.
When the mast was back up, I was underway in about twenty knots of wind when the
starboard triangle plates which attach the lower stays to the mast failed precipitously.
I immediately swung the boat around to put the load on the other side of the boat,
and saved the mast which was significantly bowed by the increased load from sustained over
load. Once on the opposite tack, the port stays took the load completely, and I was able
to lower the sails.
Later I replaced these triangle plates on both sides, with aircraft grade 316
stainless plates, double the thickness of the original parts.
No sooner had I finished replacing these plates, then, when I was underway in 25
knots of wind, the spreader bracket on the the starboard side failed (probably from a
crack caused by over-load in the first incident of metal failure).
To replace the spreader bracket, I worked with Pipeworks in Long Beach, California,
which built a new bracket in a week by copying the old one. Pipeworks has a plasma cutter
which can follow a pencil tracing, and they do a very nice job with these brackets. Again,
I requested 316 stainless, and greater thickness than the original design. The quality of
the replacement was a full step above that of the original.
I am writing to record my experience with these bracket failures, (not only on my
boat, but also on another Offshore 27 in the San Pedro area). The brackets failed suddenly
and completely. There was no visible sign of cracking before the failure.
My conclusion is that after 27 years of use, these brackets have seen too much
flexing, and too much grain boundary growth to be serviceable any more. Moreover the
quality control on the smelting of stainless steels in and around Hong Kong in the 1960's
was no where near as good as it is today.
For those who are doing a full restoration of a Cheoy Lee of late 60's, early 70's
vintage, replacement of all the structural fittings on the mast merits some consideration.
Re: Fatigued Mast Brackets, Failure
& Replacement
From: Carey
Date: 9/6/98
Comments
I must agree about replacement of Cheoy Lee stainless. I have owned an Offshore 47, Luders
design ketch 1973, since 1985. I have replaced every bit of Cheoy Lee stainless except the
feet on the stern pulpit (soon to be done!). 2-1/2 years after buying and cruisng from So.
Ca to Florida we found all the chainplates to be under fatigue--to the point that some of
the chainplates could be gently knocked over with a hammer. Also, the mast tangs, uppers
and lowers on both masts had been welded at the bend instead of "bent". They
showed crevice corrosion and were also replaced. "Dazzler" was owner equipped
with "Sparlight" aluminum masts (now known as "Proctor") so I don't
know the origin of the tangs.
I would strongly encourage owners of
those 60's and 70's era boats to look into their stainless.
Refinishing Wooden Spar's
From: |
Hlennox |
Posted: |
1/4/99 |
How offen do you refinish wooden spar's (Clipper Ketch)? Is
there a set rule?
Thanks
Hlennox
From: |
Todd Sperry |
To: |
Hlennox |
I'm refinishing my spars as we speak. They were varnished
when I bought the boat two years ago. In that time the varnish completely deteriorated. As
I've got the masts down
now, I'm taking the expensive step of doing something different. I've decided to use
Awlgrip, and have it sprayed on. The cost for the primer, paint, application, and
materials will be approx $800-$1000. My hope is that I won't have to do this again for at
least five years.
Thanks,
Todd Sperry
From: |
Chris Nunns |
To: |
Todd Sperry |
I've just done the opposite! My masts
were paited white when I bought my Offshore40. The 2 pack white paint lasted 12 years
without peeling but I lost the mizzen mast thru rot which could not be seen under the
paint. The mizzen replacement is on hold and I'm now sailing a sloop with a beautiful
varnished mast. I have to overcoat every 3 months (in the tropics - perhaps less
elsewhere) but it looks great AND I can see what's happening underneath. Wooden spars are
a major maintenance headache - so we might as well show them off!
replacement masts
replacement masts
From: Brian
Date: 8/17/98
Comments
I am just beginning the restoration of a 42' Cheoy Lee '71 Clipper and have read with much
interest the issues concerning the masts, spars and the glues used. My question to anyone
out there is, what is the availability and/or cost of replacement aluminum masts? I would
prefer a direct size replacement because of the existing sail inventory but would also
like a taller rig if that can;t be accomplished. Anyone out there have any feelings on the
subject? Brian, San Diego
Re: replacement masts
From: robert c.
Date: 9/14/98
Comments
generally when you go from wood to aluminum people say that you can increase rig height a
foot or two without difficulties. this is because of the reduced heeling moment of the
lighter aluminum over the heavier wood, acting against the same amount of ballast.
Brian,
Is this a
Clipper Ketch? I wouldn't switch to aluminium myself but if you've made up your mind I
might make you an offer for your mizzen mast! I'm only half serious (I live in Singapore)
but I'd hate to see it cut in half and used for propping. I need a mizzen mast just 24ft
long (yawl rig) and approx. 5" x 3" at the base. Yours (if it's a ketch) may be
too big a section. Any other members looking for wooden spars?
From: |
shimkonis |
To: |
James McGarvey |
I have a
42 clipper ketch-if you have the spars i'd recommend stripping and redoing.i can tell you
we removed the masts to restore and without the weight the boat bobbed unbeleivably.I ran
into a guy last week who switched to aluminum on a similiar boat and indeed it was more
tender.i have a boat in excellent shape and have made many improvements ,including ways to
cut maintenance. contact me if interested.
Fastener Holes
For
reduced maintenance I plan to do the following to reduce the possibility of rot and to
increase the holding power of the fasteners. In Nigel Calders book "Boatowner's
Mechanical and Electrical Manual" he writes concerning wooden spars that "Any
fastener, even when properly bedded but especially when improperly bedded, is a potential
source of water ingress and thus rot....the Gougeon Brothers (manufactures of West System
epoxies) have shown that an effective answer is to drill an oversized hole, fill this with
epoxy, and set the fastener in this epoxy plug. The epoxy penetrates and bonds to
the surrounding wood and, with a considerably larger surface area than the original
fastener, dissipates the load..
The steps are as follows:
Drill a pilot hole to depth of fastener
Drill the oversized hole to a little less than depth of fastener
Fill hole with epoxy and top up as the wood soaks it up.
Clean fastener (acetone works well) and install it when the epoxy begins to get. The
section of fastener that runs down into the pilot hole should provide just enough grip to
snug up the fastener until the glue sets."
Restoration Story of Mast/Rigging for Frisco Flyer
Hi James,
Boy did I enjoy seeing
the picture of the mark I Frisco Flyers being built in your
History of Cheoy Lee page! I have a contribution for you spruce spar page.
Recently I decided to tackle the project of restoring the rigging and mast on my
1958 teak Cheoy Lee Frisco Flyer, fractional rig.
The successful attempt at unstepping the mast transpired by tying my boat next
to the Juanito's marina office in Ensenada, having a friend on the roof holding the
top of the mast while lashed to a flagpole, and a number of helpers to lift out the
mast. Then the mast was taken by pickup to my friend's house where it was laid
on the roof until the next week.
The problem was a number of cross grain cracks inches above the deck, there was
a single crack on both the port and starboard sides, and a crack in the front where
a hole had been drilled. The rigging had been loose which I think caused the
side cracks.
I purchased from Frost Hardwoods in San Diego a large piece of air dried stitka
spruce. I selected a piece with very close rings which I believe to be slow growth
wood of higher strength. It is very important not to use kiln dried spruce as the
kiln drying process destroys the elasticity of the wood which is necessary for
spars.
The mast was put on saw horses on the ground. I used a japanese hand saw and cut
many cuts cross grain through the port side wood section, being very careful not
to cut the center piece of wood. These moon shaped pieces were then broken out
with a hammer and chisel. This left the mast with about a 2 ft section of 1/3
semi cylinder removed. The next step was to taper in the 1:10 slope scarf tapers
at each end of this removed section.
The taper was jigged up by clamping two parallel strait pieces of lumber each
diagonally against the sides of the mast. I used 4 large woodworkers wood
clamps
for this. This jig was used as a guide for planing. Then I began the long job
of
planing, diagonally across the jig lumber rails. Later, on other tapers I reduced
work by cutting out rough steps before planing. The large hand plane we were
using took a long time, so on the next weekend I brought a Dewalt power planer.
A taper was made on both ends. The end of the tapers near the middle section
was difficult and was done with coarse sandpaper on a block slid across the rails.
In the forward section of the middle wood was a crack, so that was chiseled out
too for another smaller dutchman to replace the wood. A sanding disk on a drill
helped out a lot for this little part.
The dutchman (piece to replace the removed wood) was made by cutting my
spruce lumber in half on a rough diagonal, to be the diagonal on one end of
each dutchman, and not waste wood. This cut was done with a table saw and
a friend to help. I planed the rough lumber to allow handling and marking.
I measured the length and depth of each taper and marked the slope on lumber.
The lumber was then clamped down and the tapers planed into each end. The
lumber was of enough thickness that planing the tapers too far could be corrected
by planning the center section of the dutchman to move the tapers farther apart.
On the mast I spread powdered blue chalk. Then put dutchman in place wiggled
it and/or clamped it, and then removed it. This marks the high spots which were
then planed off. This was repeated until there was no more than one millimeter
gap anywhere. The blue chalk was vacuumed off and sanded off.
For the mini dutchman for the center fore section, I just marked it by holding the
wood next to the cut section and traced the shape onto the wood which was then
planed to shape.
Then every surface to be in contact was covered with epoxy and clamped together
with 4 large woodworkers clamps. Use wax paper so that the clamps don't get
glued! Putting lumber to distribute the load between the clamps and dutchman is
the way to do it. The clamps were then tightened tight, but only once, not as the
glue cured!
The whole process of cutting out, shaping, and gluing was then repeated for the
starboard side of the mast. As of the moment, the boxish outsides of the scarfs have
been roughly shaped and wait for next weekend. There was no bend in the mast
from this whole process in which the mast was almost cut in half because one
side at a time was done.
Some of the seams farther up the mast were delaminating in places. It looks like
someone tried to re-glue them with the mast in place because I was able to pull
out the old glue by using a sheet metal scraper with a hook ground into it.
I just
slipped it behind the glue and pulled it out! So I cleaned out the seam with my
favorite thin bladed japanese hand saw and filled it with epoxy.
All the hardware was removed before starting work which will allow a great
varnish job. This scarf job removed a lot of unwisely drilled holes in the mast.
There were 3 cleats screwed into the mast, and two plates for jumper shrouds
screwed into it. The jumper screws were worked until they were not orthogonal.
For these jumper plates, I will drill all the way thought the mast and use long
through bolts. This will prevent working of the fasteners and destruction of the
wood. The cleats will not be re-installed. Bronze cleats will be welded to the
collar of the gooseneck. This will eliminate 6 holes in the mast.
All new rigging wire has been made by Pacific Offshore Rigging here in San
Diego for $614.
In a couple more weekends, I will be happy with my rig restored like new.
I am also replacing the boom. The boom became delaminated, two 3/4 inch pieces
glued together, then the single point boom vang mount (also not through bolted)
caused cross grain cracks near the screw holes. The original folkboat had a vang
attached at two points to distribute the stress along the boom, a much better
idea. The new boom will also not have a sail grove which stores moisture at the
edge of the lamination. I will use a loose footed sail.
--
Karl Enrique Ihrig
http://www.cadence.com
Cadence Design Systems, Inc.
15015 Avenue of Science
San Diego, CA 92128
email: ihrig@cadence.com
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Latitude: North 32^59'16.9"
| c a d e n c e
| Longitude:
West 117^04'45.9"
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