Boats &Gear
E ric S loth
upgrade your chart machine PG. 34 • environmentally friendly bottom coatings pg. 36 • drive choices for pumps pg. 38
By charlie ess
S
hould you happen to stumble upon
Eric Sloth’s Sloth’s Fiberglass at
the east end of the Northern Enterprises Boat Yard in Homer, Alaska,
you’ll find a boatbuilder who’s having a
big impact in his part of the world.
Sloth is incorporating some of the core
materials, new designs in glass fabric and
epoxy resins that have dominated the sailboat world into repair jobs on older boats
that were built originally with plywood,
mat and polyester resin.
Even more important for commercial
fishermen, he’s learned how to offer the
technology at prices that have led more
than a dozen seine-boat skippers to line
32 National Fisherman • august 2000
up for work at the shop. “It’s America’s
Cup technology brought to the fishing industry,” says Sloth.
In late winter, Sloth and seven employees put that fiberglass technology to work
when they cut three boats in half to lengthen them and do other work. The Tahaja,
a 38-foot salmon seiner from Chignik,
was in for a 4-foot stretch, a new deck,
aluminum rails and an exhaust system.
The Sea Breeze, another 38-foot Chignik
seiner stood nearby. She was due to be
lengthened 5 feet and have a new deck
and tophouse added. At the same time, 7
feet was being added to the Millennium,
a 50-foot herring and salmon seiner from
Homer, that was also getting a new RSW
system and deck.
Part of the reason behind the shop’s
E ric S loth
An Alaska boatyard has quite a reputation for cutting up boats
and then putting them back together with modern composites.
longer and lighter, the Santiago (ex-Tahaja) is one of three boats that was
lengthened and had water-soaked plywood decks replaced at Sloth’s Fiberglass.
burgeoning popularity rides on the fact
that Alaska’s salmon season proved
profitable for many skippers this past
season. Thus they can afford to pay the
$100,000 it cost for work on a boat like
the Tajaha.
Another reason is that the materials
going into the hull extensions, decks and
wheelhouses offer comparable strengths
but at half of the weight of the previous
C harlie E ss
C harlie E ss
expenses were cut when the Sloth crew started using this impregnating table
to build up laminates instead of wetting-out fiberglass in the boat.
components, which were layers of marine plywood encased in fiberglass laminates of mat, woven roving and polyester resin.
Epoxy vs. resin
Though polyester and epoxy resins
weigh about the same, epoxy’s strength
allows the use of stitch mat, in which longitudinal glass fibers are stitched together
side by side, instead of alternating layers
of chopped mat and woven roving.
“Epoxy enables us to do a higher fiberto-resin ratio, and the fiber is the strength,
not the resin,” Sloth says. “The fibers
are already stretched out,” he says of the
stitch mat, “ready to take a load.” Which
means that an epoxy laminate takes about
40 percent less resin to achieve the same
strength as polyester laminates.
Sloth discovered the huge savings in
weight as part of conducting tests to certify that his components met standards
with the American Bureau of Shipping.
According to Sloth’s computations, a hull,
deck and house built of epoxy resin and
a foam core would weigh 50 percent less
than the older composite construction. Because the engines, reduction gears, electronics and other components weigh the
same, the overall boat would weigh 15
percent less.
The joy among boat owners is that by
using vacuum bagging in the laminating
process, lightweight decks should stay
lightweight in the years ahead, unlike the
plywood-cored counterparts, which absorbed water like a giant wick — a point
that Jeff Sinn, one of the crew at Sloth’s
Fiberglass, says became evident with the
removal of the old decks.
“A two-by-two foot chunk of the watersoaked deck (made up of two layers of
3/4-inch marine plywood) was about all
the guys could cut out and throw overboard,” Sinn recalls.
The Tahaja’s new deck consists of a
1-inch balsa core, encased in a 1/8-inch
layer of epoxy fiberglass on the underside
and 1/4-inch layer on the top.
The deck sections were partially fabricated on a 5’ x 32’ laminating table. The
resin-soaked Knytex stitch mat lay against
the smooth metal table, which had been
buffed with a wax release agent. Sections
of balsa core were placed atop the wet
after removing the old plywood and glass wheelhouse, workers built the new one
from closed-cell foam core and epoxied fiberglass that was then vacuum bagged.
laminate, then sealed under a large sheet
Sloth says the hull stringers in a boat
of plastic, which had been secured to the
stretched 5 feet are sistered for 15 feet,
laminating table with butyl tape. Sinn then
and he uses 25 lineal feet of fiberglass
turned on a vacuum pump that sucked
to overlap the 5-foot opening in the hull.
air from underneath the plastic sheet and
Before the glass is laid down, however,
pulled the core against the laminate with a
Sloth, Sinn and the crew cover the gap
pressure of 13 pounds per square inch.
between the two hull sections with sheets
Vacuum bagging creates a tight bond
of 1/8-inch, finish-grade plywood, taking
between the laminate and the core. The
care that the wood form matches the outresin from the laminate is drawn up and
side curvature and roundness of the hull
fills the pores of the balsa.
and chines.
“That won’t be able to hold water,”
The first layers of laminate are laid
Sinn says of the resin-impregnated balsa.
against the waxed plywood from the inThe crew laminates and vacuum bags the
side of the boat. After the early layers of
topside of the deck
the laminate have
after it has been incured, the plywood is
stalled on the boat.
removed. Sinn takes
“A two-by-two foot chunk
“We can’t do both
a fairing stick and
sides at once,” Sinn
marks out hills and
of the water-soaked deck
says. “Otherwise the
craters on the newly
deck won’t bend to
laid section of hull.
was about all the guys
fit the camber.”
The low spots will be
Though manufilled with extra laycould cut out and throw
facturers offer syners of laminate while
thetic foams (Sloth’s
the high spots will be
overboard.”
shop uses Core-Cell)
ground until the new
that approximate the
section blends with
—Jeff Sinn,
strength and density
the lines of the old
of plywood, Sinn says
boat.
sloth’s fiberglass
many of the skippers
Depending on the
insist on staying with
nature of the task,
the “tried and true”
the crew picks one of
double-3/4-inch layers of plywood in sectwo hardeners to set up the resin.
tions of deck immediately under the masts
“If we plan to do shaping the next day
and deck winches.
[on the outside of the hull] we’ll use a
The panels that compose the wheelfast hardener,” Sinn says. If, on the other
houses, meanwhile, have been constructhand, the crew plans to continue building
ed on the laminating table from panels of
laminations on the inside of the hull, they
1/2-inch foam core and the epoxy lamiuse a slow hardener, which remains tacky
nate.
throughout the following day, thus creating a strong adhesive bond for the subseLaser fair
quent laminations.
As for the process of lengthening the
When it comes to the bond between
boat, the crew aligns the two parts of the
the epoxy addition and the polyester hull,
hull that have been cut apart and placed
Sloth says that epoxy’s adhesive qualities
on cradles with a laser that shoots a beam
prove superior.
through the cutlass bearing. The rear secEfficiency gained
tion of the boat is maneuvered so that the
It’s in the process of stretching the boats
beam hits the center of the output flange
that the crew realizes the first in a string
on the reduction gear in the front half of
of epoxy efficiencies over working with
the boat.
polyester resin. Namely, the epoxy resin
The insides of the two parts of the hull
doesn’t generate heat in the hardening
(including the stringers) have been ground
process like its polyester cousin.
back at a shallow angle to allow splicing
“We’d be doing polyester lay-ups in a
in the new fiberglass buildup, much like a
mold for a week,” Sinn says of building
scarf joint in carpentry.
the thickness of the new hull section to
match the old, which often measures 5/8
inch along the sides of the boat, an inch
at the chine and 2 inches near the keel.
“When it comes to the skin in a polyester
stretch job we could hardly do a quarterinch lay-up at a time, whereas the epoxy
doesn’t heat so we could effectively do
the laminating, full thickness, in two afternoons.”
“The main thing is an open lay-up
time,” Sloth says. “We have all day before it cures. We don’t have to grind between steps. We don’t have buckets of
resin kicking off and people panicking on
a hot afternoon.”
When it comes to shaving the costs of
labor, both Sloth and Sinn agree that using the impregnating table has been a key
ingredient.
“I used to have to pull four guys away
from other projects,” Sloth says. Now, it’s
a one-man show. “Every six minutes Sinn
can give us 30 lineal feet [of wet laminate],” Sloth explains. “I wouldn’t dare
do this with the old polyester technology.
Now, we’ll fire up at two in the afternoon
and be done by four. We’ve shifted the
manpower away from the table and into
the boat.”
As for the costs of materials, Sloth
uses System 3 resin, which runs $3.13
per pound, or about $1,600 per barrel as
opposed to $600 per barrel for a drum of
polyester resin. But a key consideration
in the final price of the shop’s work is
that vacuum bagging epoxy laminates
and cores cuts resin consumption to a
third of the quantities used in a standard
polyester laminate, according to Sloth.
That’s one of the reasons he says, “it’s
not more expensive for me to build”
with epoxy.
Though there are a lot of variables such
as the costs of labor, and the shipping of
materials, Sloth estimates he could offer
a total boat package for around the same
price as a shop using conventional materials. But for now, he’s satisfied that the
repair jobs keep coming his way.
“We’ve used 20 drums of resin since
Thanksgiving,” Sloth says. “For a repair
shop, that’s getting right after it.”
For contact information on companies
mentioned in this article, see page 61.
august 2000 • National Fisherman 33