24
August 03: I got two sheets of lauan and two
2x10x8-foot planks of hem fir from the friendly local
home
store. I had thought that I was
picking through a pile of spruce and only found my error
when loading the planks into the truck.
The ply is good, with a reddish face I like for the
interior and a lighter A-face for the exterior. The
wisdom of using the A side in and the B-side out doesn’t
get the nod with this lauan when I am going to be finishing
the boat bright. The reddish face is far prettier and
I like to see it on the inside of the boat. Also, putting
the A-face out makes the painting go even quicker.
As
with the last sheets of lauan that I got, I again noticed
a strong aroma of bananas – the mystery wood in
the core layer, I suspect. It sure is different than
the pine smell that I like but is pleasant in its own
way. Suggests Banana
Boat as a boat name ... . At any rate,
it smells better than the hem fir, which has an unpleasant
aroma when freshly cut.
I’m going to rip the hem fir and see if the grain
is good. The planks are fine, with only a few, big knots.
At $6 each, the two hem fir planks were a bargain –
if hem fir strips will bend without breaking, that is.
I recall a reference to hem fir on the Internet, I think,
as being a poor boat wood, but that was one comment.
I’ll decide for myself. Building boats is really
just solving design and materials questions, I believe,
so my mistake in selection really wasn't’t a mistake.
Something like an unexpected opportunity. I’ll
also do a word search on hem
fir to see what’s out there. Here
is a link to a wood products industry
site, which accounts for the lack of any mention of
hem fir’s aroma. My Dad would have called it piss
fir instead of hem fir. That was the
usual nickname in the woods for white fir. Dad was a
logging truck driver.
The thing that tipped me off
that I had not gotten the spruce that I had intended
to get was seeing Tillamook
stamped on the planks. Been there. Tillamook is in a
prime Douglas fir zone, on the northern Oregon coast.
I immediately had a mind picture of a sawmill that I
drove by once in the Tillamook River Valley not too
far from the town and the cheese factory of the same
name. This mill was at a crossroads, where the coast
road turned inland after miles and miles of tracing
the seaward edge of the Tillamook Burn, an immense forest
fire disaster caused by logging practices in the 1930s.
My dictionary sez that hemlock
fir is a term for spruce – genus
Tsuga,
family Pinaceae.
The industry website says hem fir is a marketing category
that includes five woods including silver fir and white
fir that share certain characteristics. I noticed that
the pieces that I cut were notably light, flexible,
and strong. But that smell ... .
After being around the smell for a while, I realized
that it also reminded me of the times that my dad would
take me to the mills or into the woods in his logging
truck.
When I had laid out the sides
of the Flats
Rat, I decided to sandwich the two sheets
and cut both sides in one pass. I used the circular
saw set for a shallow cut. The cut got away from me
at one end, so I had to re-fair the line, losing a fat
inch of depth. The curve looks fair, though, so I didn’t
throw out the cut sides and start over.
I’m curious to see if this boat handles any differently
because of this error and fix. I figure that I’m
close to prototype work here, so I’m going with
the re-faired curve. The error is far greater than I
would accept if following plans, especially on a bigger
and more expensive boat, but establishing a fair curve
is still fundamental to any lofting-type work such as
this on a boat.
I
made the mistake because I’m still a novice, really,
at using a circular saw to make a cut like this. I’ve
been using the circular saw instead of the saber saw
for cutting ply, because the cuts, though harder to
control, are smoother and quicker with the circular
saw. Just watch for kickback; the durned things kick
back with almost no provocation.
25 August 03: I’ve decided to
cut the bow and stern transoms and the forward and aft
bulkheads to fit the sides as adjusted for my error
in cutting the bottom curve. If I take the measurements
from the side pieces as cut, which I’ve scribed
for the bulkhead placements, I should get away with
a minimum of planing, or adding shims.
I used the plans that are available from www.shortypen.com
to have a reference point for the placement of bulkheads,
but I moved them in slightly to partially compensate
for the loss of the inch in depth, and to bring the
center of balance forward some, too.
I marked one vertical line and indicated the other edges
with broken lines.
Costs:
plywood (two sheets of 1/4-inch lauan underlayment,
which is actually closer to 3/16ths of an inch thick,
or 5 mm) – $20; hem fir – $6; boat nails
– $6.
Time
spent so far: 3 hours.
I marked the transoms and bulkheads on the A-face of
the plywood because it’s lighter than the ruddy
red B-face. You use the factory edge as a reference
point for drawing lines when cutting out. Also, I marked
bow
and stern
because the ends were within 3/4 of an inch of one another.
I put all the scribe lines on the inside of the side
pieces. They won’t show much if at all because
of the air chamber spaces. I was careful to account
for the width of the bulkheads – 1/4 inch for
the ply plus 3/4 inch for the frame sticks.
I
left about a 1/4 inch between each plywood piece as
I laid them out, to account for the saw kerf and inevitable
tearing. It’s always best to leave a margin, but
not too much. Many times the plywood is allocated with
the barest minimum of slop. If you make small errors,
you can find yourself with too little plywood to make
all the pieces that the plans call for.
I also attended to the grain direction, because I know
from bitter personal experience how easy it is to lay
out pieces wrong and end up buying an extra sheet of
plywood to compensate. I like to use a wood straight-edge,
a rafter square, and
a dead-accurate engineer’s square that I paid
about $20 for.
If I can’t reference a scribed line from a factory
edge on the plywood, I use the steel tape measure but
not from the end. I either line up from the 1-inch mark
or the 10-inch mark, etc., to get accuracy. Just double-check
your marks; it’s easy to forget to calculate correctly
in these cases.
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Measuring
trick: Use the 10-inch mark and read it as "1"
to get an accurate measurement by avoiding the
hook on the end of the tape measure, which can
throw you off if you try to line up a mark like
this.
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I cut the scribed plywood out
by eye with the circular saw, leaving a margin. Then
I used the bandsaw to cut each piece out, leaving the
lines as reference points for placement of the frame
sticks. I can either trim with a block plane or belt
sander, or I can cut and nail/glue the wood frame strips
to the line and sand after, which makes everything easier
to assemble and more accurate, too.
I’m still finding my way with the bandsaw, so
cutting close to the line gives me a margin for error,
since the blade wanders some. And at the same time,
I get practice time on the bandsaw, which was a birthday
present a few months ago.
26 August 03: I set up a thin-kerf
table saw blade that I got from Dave
Carnell. The blade has carbine tips
but only cuts a kerf 1/6 of an inch wide instead of
the usual 1/8 of an inch that regular carbide blades
cut. The first cut in the hem fir smelled like Dad’s
piss
fir. The grain is good, though. I got
11 strips of 3/4 by 1 ½ inches by 8 feet from
the 1x10x8-foot plank that I cut.
These ripped pieces will be the external chines, the
gunwales, and the frame stick stock for the transoms
and bulkheads. I’ll leave the frame sticks that
will be beveled the full width, and I’ll leave
the sticks that won’t be beveled at 3/4 by 1 ½
because the wood is light and the extra won’t
make much difference.
The chines will be 3/4 by 1 inch and the gunwales will
be 5/8 inch by 1 1/4 inch. Make that 3/4 by 3/4 for
the chines. I discovered that the bigger piece can’t
make the bend. I also can cut so the grain is helping
make the bend – using flat grain instead of vertical
grain. A slash or flat grain board yields vertical grain
ripped boards, which are generally superior except when
the vertical grain inhibits bending to a curve.
Cutting to 3/4 by 3/4 yields an off-cut of 3/4 by 11/16s.
There are uses for these off-cuts, such as laminating
paddle blanks. The gunwales are cut to 5/8 inch to save
weight higher up in the boat (probably more of an illusion
than a savings, but it also looks less bulky on a boat
of this size).
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Chines
and gunwales ripped to size from hem fir.
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Some
of the ripped hem fir is warping already, which is actually
preferable, because it helps make the curves when the
boards are already bending in the right direction before
being put into place.
Time: 1 ½
hours to rip the hem fir.
After I stopped for the night last night, I realized
that I had not cut the bevel for the bow transom in
the plywood sides, so I did that. I sandwiched the sides
together and picked up the angle of the bevel from the
plans, using a sliding bevel gauge.
I’ll
have to cut a new bow transom, because I picked up the
wrong dimension when I forget to take the bevel into
account. I made sure that there was enough plywood left
to cut a new bow transom and still have enough left
for the decks.
I decided to true up the bow
and stern transom pieces so that the A-sides will be
on the exterior of the hull. The bulkheads are scribed
on the A side, so I can use the other method of nailing
the frame pieces to the scribed lines, but I decided
to true them up, as well.
The belt sander made it a quick job. The block plane
works well, too, but you have to watch for tear-out
on the corners.
Time:
1 hour.
The next step was cutting the bevels for the frame sticks.
The bow and stern transoms have beveled sticks on the
sides and the bottom. The bulkheads also have bevels
on the sides and bottom.
You need to take care to cut the bevels in the proper
directions. I use the table saw to rip cut the bevels.
Since I had to change the bottom curve to fix my cutting
error, I picked up those bevels from the side pieces
with the sliding bevel gauge.
I generally cut the top and bottom frame pieces full
width and piece in the sides to fit. By cutting long,
I can trim with the Japanese
pull saw to make it nice all around.
I tried to orient the wood grain so that any cupping
would bring the stick closer to the plywood instead
of opening a gap. This takes some effort but is a good
thing to do.
An
alternative way to cut the frame bevels is to nail and
glue up, then cut to lines drawn with a straight-edge.
The side bevel needs to be cut before the sides are
joined to the transoms and bulkheads, but the top and
bottom bevels can be cut after. Or you can use a circular
saw or handsaw. I like the table saw for this job.
If
you make errors, you can usually fix them. Think it
through first, and visualize the boat’s various
angles. Study the plans. Then sin boldly! It’s
your boat. Set your own standards.
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Glue
and boat nails attach beveled wood strips to
the bow transom. Bevels were cut before the
piece was assembled. The Japanese pull saw will
make short work of the excess on the top and
bottom strips.
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I used 3/4-inch silicone bronze
ringed boat nails and Elmer’s Probond glue to
assemble the transoms and
bulkheads. I used a two-one-two pattern in placing the
nails. The glue is waterproof and nontoxic – and
much cheaper than epoxy – $52 per gallon vs. $12
per gallon.
I put epoxy over the joints and seams, in and out, if
I want to increase the waterproofing, though on this
boat I’m not planning to use any epoxy.
Fifty hours of work and $100, more or less, will give
me another such boat, so I’m opting for no epoxy
at this point. It’s a test of the ability of the
Elmer’s glue, too. (Note
from later: I did use epoxy on the interior
joints).
Since the top frame sticks for the two bulkheads don’t
take bevels, I nailed and glued those pieces before
cutting the bevels for the side and bottom pieces. That
gave me a substantial and accurate baseline. I left
the top pieces full width for a touch of extra strength
for the decks.
In placing the nails, I tried to anticipate the possibility
that some trimming may be necessary. I left a bit of
extra space on the top sticks because if I attach the
sides to the transoms and bulkheads right side up, any
extra will stand proud of the gunwale lines. Bronze
boat nails sand well but can nick tool edges. I usually
have to sand some nails to get fair lines. We’ll
see how it goes this time.
I didn’t use any clamps because the boat nails
are spaced closely. And clamps are a pain sometimes
and leave dimple marks if you don’t fiddle with
wood blocks to protect your work from the clamps’
tendency to leave depressions and dimples. Sometimes
I just clamp and deal with the dimples later.
I put the bottom frame sticks on wrong on the aft bulkhead,
so I’ll have to re-cut it after the sides are
attached. Didn’t check twice.
Time:
4 hours to finish the transoms and bulkheads.
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Centerline
marked clearly on table that will be the strongback.
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27 August 03:
I set up my 2-foot by 5-foot plywood-top workbench as
a strong back. First I drew a centerline, then a line
for a batten to hold the aft bulkhead true and untwisted.
I remembered to make centerlines on the transoms and
bulkheads.
I decided to build the hull upside down, so that the
strong back will maintain trueness while I bend on the
chines and bottom. I tried to glue as I went but had
to switch to dry-fitting first with deck screws, which
work perfectly for dry-fitting because they are self-tapping.
There is almost never a need to pre-drill for the deck
screws except for douglas fir, or at the ends of boards.
Be careful not to overdrive the deck screws if you use
an electric driver or drill with screw bit. This will
split the wood.
I used some cord to pull the sides in so that I could
dry-fit the forward bulkhead. Then I nailed the aft
bulkhead to the wood crosspiece that I cut to 3/4 by
24 inches. Then I nailed the forward bulkhead to the
table at the centerline to get a pivot point, and nailed
a crosspiece to the table and the bulkhead, lining up
the centerlines and positioning the crosspiece with
the square.
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Light
cord makes a windlass to pull in the sides at
the bow and hold them in place while I attach
the bow transom.
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Since I was at the bow, I dry-fit the bow transom first.
I attach the side to the inside of the bow piece, which
left both plywood edges exposed. I’ll treat them
with epoxy or glue then round them. If I were to go
first class, I’d epoxy putty and fiberglass tape
all the outside seams.
After I glue and nail what I’ve dry-fit, I’ll
attach a wood batten at the centerline, to make sure
the transoms stay true and untwisted, and to make sure
that I have as much bracing as I’ll need when
I bend on the external chines.
Time:
2 hours.
I pulled the boat out of line when I attached the batten,
so I pulled the screws in the bulkheads and re-trued
the bulkheads vertically, then nailed them. The boat
is within 1/32 of true now. I can live with that!
I’ll glue the dry-fit stuff tomorrow when I’m
rested.
28 August 03: I backed off the deck
screws on the bow and the forward bulkhead to glue and
nail them. Then the other two on the same side, then
the same drill for the other side.
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After
assembling the hull with deck screws, I backed
off the screws one joint at a time and glue
and nailed.
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Double-check the alignment. Deck screws can tap new
holes without much warning. Use index pencil marks,
and leave the screw points out enough to find the proper
holes. You get used to feeling the tip find the hole
as you slide the pieces.
Use paper towels to wipe up excess glue – and
use a lot of glue. Be mindful that glue will affect
the appearance of wood finished bright, even with varnish
alone. The glue can cause a mottled appearance. If it
is necessary, you can use a wet paper towel to remove
the glue.
Since the exterior of this hull is to be painted, I
drew a line to show where to nail. I used 3/4 inch boat
nails on 3/4-inch centers. The wood behind is soft,
and the glue needs help since I’m not clamping.
Boat nails have the holding power of screws because
of the rings on the shank. The deck screws will come
out when the glue sets. I’ll putty the holes they
leave with glue thickened with wood flour.
I glued and clamped a shim to
the aft bulkhead – no nails, though. I’ll
plane it flush with the rest of the frames to prep for
the bottom piece of plywood.
Time: 1 ½
hours.
Costs:
$10 for varnish and $6 for nails.
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External
chines clamped in place.
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29 August 03: The next step –
bend on and glue/nail the external chines. I chose to
use external chines because they require no notching
of frames, unlike internal chines. In a displacement
hull, any water flow problems are negligible. And some
say that external chines actually improve water flow
past the hull.
I used more of the hem fir for the chines, 3/4 by 3/4,
which let me use the grain direction with the greater
amount of flex. The first one went on easily, in fact
easier than the high-grade pine chines on the first
Flats Rat that
I built. The idea is to bend on both chines to minimize
forces that lead to hull twist. When you glue and nail,
you remove clamps equally from each side and reapply
them as equally as possible, too.
I like to install half of a chine at a time, and to
this end I double-clamp at the midpoint, and I use a
pencil mark to line up the side and chine at each spot
where a clamp goes. Careful marking of carefully place
clamps will ensure that there are no gaps between the
chine and the plywood. I have about 15 clamps, and I
usually wish that I had a few more. I used 3/4-inch
boat nails to secure the chines to the plywood.
The fair curve of the clamped chines revealed a hump
of plywood that was out of fairness on each side aft.
I planed the sides to match the chines. Also, I placed
the chines to favor the line they curved to rather than
the curve cut into the plywood. This is a second check
of fairness.
I used two hammers to drive the boat nails – one
to hit with and one on the other side to absorb the
blows and protect the wood from flexing and possibly
splintering. Remember to run a pencil along the chines
to show where the glues goes on.
I quickly switched to using a pair of pliers to hold
the nails while giving the first taps with the hammer.
That speeded up the job, and saved my fingers.
Time: 2 ½
hours.
Cost: Epoxy at
$10.
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Straight-edge
board shows high spot on bulkhead.
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The next job was to use the belt sander to fair up the
chines and the bottoms of the transoms and bulkheads.
I used a straight board to make sure that all was true
in preparation for the bottom piece of plywood.
I don’t bother with leveling
my building forms or boats, because in 30 years of woodworking
paired with a certain amount of moving about, I never
have had a wood shop with a level floor. I make sure
that the boat is true to itself from side to side. I
use a straight board to eyeball surfaces for fairness,
and I use various tools such as sanders and hand planes
to br9ing surfaces into readiness for plywood sheathing.
My eyeball is accurate to 1/64th of an inch.
Time:
1 ½ hours for fairing.
There is a point in any boatbuilding project where you
must decide what angle to cut various pieces such as
the ends of the chines and gunwales. For the first Flats
Rat that I built, I chose 45-degree angles for these
cuts. I’ll use the same angle here.
These angles are actually compound angles. You follow
the edges of plywood as a guide while cutting to the
45-degree angle scribed on the tops of the pieces.
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Checking
the fairing of the chines in preparation for
scribing, cutting, and nailing and gluing the
bottom onto the hull.
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30 August 03: The bottom of the hull:
