OTHER MAST ISSUES ADDRESSED
In addition to the sheaves, I took the opportunity of having the mast down to address some other issues. The
rig inspection when I purchased the boat was limited to looking at the rig with binoculars. That will reveal a
glaring defect, but is of course no substitute for a careful inspection. The shroud tangs, spreader
attachments, mast step, mast top, and other areas all look to be in fine condition. The only exceptions were
the Windex, which was replaced, and the mast step, which was absolutely filthy (more on that below).
I also took the chance to carefully inspect the jib and spinnaker halyard sheaves. They are in great shape,
which is a relief. All of the mast mounted bulbs were burned out, so these were replaced as well. I retaped the
base of the spreader boots and cleaned the rig.
The only thing worth noting is the amount of mud in the mast base and the mast step. They were literally
filled with mud and old wasp nests. I'm sure the mud came from mud dauber wasp nests. A big part of
cleaning the boat after purchase involved removing the many nests (easily 50 or so) from the inside of the
boat. The photos below show the mast base. The step was in the same condition. Although it was easy to
clean, I was unsure for a minute if I was working on a sailboat or shoeing a horse. It's very obvious the rig
had not come out of this boat for many years.
MUDDY MAST BASE
JIB/SPIN HALYARD SHEAVE BOX JIB/SPIN HALYARD SHEAVE BOX
In addition to the sheaves, I took the opportunity of having the mast down to address some other issues. The
rig inspection when I purchased the boat was limited to looking at the rig with binoculars. That will reveal a
glaring defect, but is of course no substitute for a careful inspection. The shroud tangs, spreader
attachments, mast step, mast top, and other areas all look to be in fine condition. The only exceptions were
the Windex, which was replaced, and the mast step, which was absolutely filthy (more on that below).
I also took the chance to carefully inspect the jib and spinnaker halyard sheaves. They are in great shape,
which is a relief. All of the mast mounted bulbs were burned out, so these were replaced as well. I retaped the
base of the spreader boots and cleaned the rig.
The only thing worth noting is the amount of mud in the mast base and the mast step. They were literally
filled with mud and old wasp nests. I'm sure the mud came from mud dauber wasp nests. A big part of
cleaning the boat after purchase involved removing the many nests (easily 50 or so) from the inside of the
boat. The photos below show the mast base. The step was in the same condition. Although it was easy to
clean, I was unsure for a minute if I was working on a sailboat or shoeing a horse. It's very obvious the rig
had not come out of this boat for many years.
MUDDY MAST BASE
JIB/SPIN HALYARD SHEAVE BOX JIB/SPIN HALYARD SHEAVE BOX
| Mast Work August 11, 2007 |
 |  |  |  |  |  |
SHEAVE ISSUES RESOLVED
The sheaves issues (detailed here) prompted me to have the mast unstepped. In addition to making the mast
head work far easier, it would also allow me to address some other minor issues and thoroughly examine the
mast itself, as well as the partners and the mast step. While not inexpensive, the process turned out to be far
more affordable than I first thought.
In order to cut down on yard time, I prepped the boat as much as I could the evening before unstepping the
mast. I removed the boom, coiled and secured the halyards, removed the old mast boot, unplugged the wires
that run through the mast, disconnected the backstay adjuster, and removed all of the ring-dings in the
turnbuckles. With this work done, we were able to get the mast out of the boat and on the sawhorses in less
than 30 minutes.
The primary reason for dropping the rig was to find out what was jamming and cutting the main halyard and to
fix the problem. I assumed that it was a sheave issue. The real cause surprised me.
The main halyard runs through two sheaves and then drops into the mast. The first sheave is in the mast
crane. The second sheave is in the center of the mast. The second sheave serves to guide the halyard down
into the mast without chafing on anything.
At some point in the past, the secondary sheave (the one in the mast section) seized. Its bearing was caked
with dirt and the sheave would not rotate. Rather than remove the sheave and clean or replace the bearing
(which is nothing more than a small bronze sleeve), it was decided to simply bypass the secondary sheave.
Bad, bad idea.
Rather than running cleanly into the mast, when the second sheave was bypassed, it ran against the top of
the mast extrusion, inside the channel for the mainsail's luff. As it was a wire halyard, it carved a sharp-edged,
v-shaped groove in the soft aluminum. Truly, I can't think of a more efficient shape for jamming and cutting
line. The photos below (click to enlarge), show the groove with the messenger line caught in it. With the new
sheaves in place, this groove will be bypassed, so the problem is solved. Also, the groove is far too small to
have any effect on the strength of the mast.
GROOVES IN MAST CAUSED BY IMPROPER ROUTING OF WIRE HALYARD. CLICK FOR DETAIL.
The sheaves were held in with just a small clevis pin and a cotter pin. It was a simple mater to remove the
sheaves. Once the sheaves were out, I inspected the surrounding area to make sure there was nothing that
would abrade the line. I found a screw used to secure the mast top cover was longer than necessary and
might come in contact with the halyard. I simply cut about 1/4" off and it sat nearly flush with the sheave
housing to which it was secured. Also, the exit on the mast crane was abraded from the wire halyard and
there were some sharp edges. I sanded them smooth.
REMOVING OLD SHEAVE BOTH SHEAVES REMOVED OLD SHEAVE
THE TWO PHOTOS BELOW SHOW THE NEW SHEAVES IN PLACE
The sheaves issues (detailed here) prompted me to have the mast unstepped. In addition to making the mast
head work far easier, it would also allow me to address some other minor issues and thoroughly examine the
mast itself, as well as the partners and the mast step. While not inexpensive, the process turned out to be far
more affordable than I first thought.
In order to cut down on yard time, I prepped the boat as much as I could the evening before unstepping the
mast. I removed the boom, coiled and secured the halyards, removed the old mast boot, unplugged the wires
that run through the mast, disconnected the backstay adjuster, and removed all of the ring-dings in the
turnbuckles. With this work done, we were able to get the mast out of the boat and on the sawhorses in less
than 30 minutes.
The primary reason for dropping the rig was to find out what was jamming and cutting the main halyard and to
fix the problem. I assumed that it was a sheave issue. The real cause surprised me.
The main halyard runs through two sheaves and then drops into the mast. The first sheave is in the mast
crane. The second sheave is in the center of the mast. The second sheave serves to guide the halyard down
into the mast without chafing on anything.
At some point in the past, the secondary sheave (the one in the mast section) seized. Its bearing was caked
with dirt and the sheave would not rotate. Rather than remove the sheave and clean or replace the bearing
(which is nothing more than a small bronze sleeve), it was decided to simply bypass the secondary sheave.
Bad, bad idea.
Rather than running cleanly into the mast, when the second sheave was bypassed, it ran against the top of
the mast extrusion, inside the channel for the mainsail's luff. As it was a wire halyard, it carved a sharp-edged,
v-shaped groove in the soft aluminum. Truly, I can't think of a more efficient shape for jamming and cutting
line. The photos below (click to enlarge), show the groove with the messenger line caught in it. With the new
sheaves in place, this groove will be bypassed, so the problem is solved. Also, the groove is far too small to
have any effect on the strength of the mast.
GROOVES IN MAST CAUSED BY IMPROPER ROUTING OF WIRE HALYARD. CLICK FOR DETAIL.
The sheaves were held in with just a small clevis pin and a cotter pin. It was a simple mater to remove the
sheaves. Once the sheaves were out, I inspected the surrounding area to make sure there was nothing that
would abrade the line. I found a screw used to secure the mast top cover was longer than necessary and
might come in contact with the halyard. I simply cut about 1/4" off and it sat nearly flush with the sheave
housing to which it was secured. Also, the exit on the mast crane was abraded from the wire halyard and
there were some sharp edges. I sanded them smooth.
REMOVING OLD SHEAVE BOTH SHEAVES REMOVED OLD SHEAVE
THE TWO PHOTOS BELOW SHOW THE NEW SHEAVES IN PLACE
UNSTEPPING AND RESTEPPING THE RIG
There's not much to report here as the yard crew did all of this work. One interesting thing was the crane. It is
ancient. I have passed it many times and I thought it was a relic that had never been disposed of. It works
though. There needs to be an operator with a large metal hook at the motor to make sure the cables don't
jump or otherwise go haywire and some parts are raised and lowered by turning a large wheel by hand. It
was covered in rust and the motor was housed in a old shed. After I got over the fear of catastrophic failure,
the crane was interesting to watch.
Here are a few photos:
UNSTEPPING:
I am watching, helpfully
RESTEPPING
There's not much to report here as the yard crew did all of this work. One interesting thing was the crane. It is
ancient. I have passed it many times and I thought it was a relic that had never been disposed of. It works
though. There needs to be an operator with a large metal hook at the motor to make sure the cables don't
jump or otherwise go haywire and some parts are raised and lowered by turning a large wheel by hand. It
was covered in rust and the motor was housed in a old shed. After I got over the fear of catastrophic failure,
the crane was interesting to watch.
Here are a few photos:
UNSTEPPING:
I am watching, helpfully
RESTEPPING
