High Performance/Low Cost Sails for Small
Sailboats
Building the Z-PDR
(Racing Version of the PDRacer)
Ryan Gray pilots the
Z-PDR back to shore after her first test run. Note the angle of the kick-up
leeboard as he powers into the sandy shore of the Intercoastal
Waterway near
Most early
Puddle Duck Racers, or PDR’s as they are known, had a
fairly boxy profile based on the basic hull requirements drawn up by David
“Shorty” Routh, the ceator
of this US Sailing certified racing class. Routh’s
class requirements were fairly simple for this 4’ x 8’
scow assuring that the bottom 10” of these boats would have the same defined
hull shape. (See the class rules at http://pdracer.com/
) Above the 10” defined hull section, however, the individual PDR
builder/designer had free reign. The creativity of design this “open” concept
allows has made the PDRacer one of the fastest
growing small boat classes in the world.
Our first
PDR Hull #100 Lame Duck was typical
of these early PDR’s. Below is a photo that shows Lame Duck in the foreground and two of four other PDR’s that I helped others to build.
The 2008 Lake Vista/Hoosier Regatta. “Lame Duck” is the boat in the foreground.
Five PDRs participated in the race. All had their hulls built in
my workshop.
Although
some of these boats carried different sails, most of the hulls were
substantially alike on the exterior. Freeboard was about 15 ½” to 16”, bottoms
were ¼” 5-ply underlayment nailed to cedar chines cut
to the rocker of the bottom, and leeboards and rudders were made to kick up for
sailing in Indiana’s shallow lakes. One major difference was in the sail plans.
While Lame Duck and another boat
carried the 60 sq. ft. Bolger leg’ o’ mutton sail, two other boats carried a 75
sq. ft. lateen and a 55 sq. ft. balanced lug sail according to the owners’
preferences. The building plan and instructions for Lame Duck are outlined in an article I wrote earlier called Camp Sailboat which is posted on my web site at: http://www.polysail.com/Camp%20Sailboat.htm
One change
that we began to incorporate after Lame
Duck was building the sides with the frames already attached rather than
building the entire framework and then attaching the sides. A second innovation
that I tried on Tom Heiser’s #223 Amakusa
Duck was to
construct the Styrofoam flotation as a single removable unit supporting a
one-piece deck instead of just filling in the side frames with foam and adding
2” of extra flotation around the inside of the boat. The initial flotation unit
was built from a single 4’ x 8’ sheet of 2” thick Styrofoam. The basic premise
behind the insert was that with the foam placed up under the deck, there would
be more flotation in that area, and if the boat were knocked
down, the boat would float higher and little to no water would be
shipped over the decks. The foam insert concept was carried
over to the Z-PDR, and subsequent flotation tests validated that theory.
The plans and pictures for that Styrofoam insert for Tom’s boat are shown below. For the Z-PDR the
insert height was cut down to 11.75 inches and curved to fit the shape of the
sides and bottom. Consequently, the shaped Styrofoam provided even more support
for the decks on the Z-PDR.
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The last two photos show the
completed Syrofoam insert alongside the nearly
completed hull.
Tom Heiser
of
Wild Duck, hull # 143, was constructed in an
attempt to establish a new PDR world record for the amount of
sail carried. At the same time, I wanted Wild
Duck to carry a rig that would allow her to be sailed wing on wing downwind
for more speed. While the hull was similar to other PDRs
I had built, the bow featured a deck and mast steps to support up to three
masts and sails.
I first
sailed Wild Duck at the 2007 Midwest Messabout hosted by Jim Michalak
at
I tested Wild Duck with various sail combinations
and found that, with her port-side-mounted leeboard, she was most easily
controlled with a single sail up in either the port or center
mast position. With a single sail up on the starboard side, the helm was
unpredictable. In 2008, I combined her 104 sq. ft. biplane rig with a 60 sq.
ft. leg o’ mutton sail to set a world record for the amount
of sail carried on a PDR.
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Testing Wild Duck’s biplane rig |
This photo taken at |
Wild Duck setting
a PDR world record of 164 sq. ft. of sail carried. |
I considered
setting the Z-PDR up for a biplane rig as well, but I was afraid that with only
about 6” of mast bury, she could not support two large sails. However, the
large sail concept was not abandoned for the Z-PDR.
Besides her 58 sq. ft. sailboard-type sail that she carried on her first test,
the Z-PDR can hoist a 100 sq. ft. balanced lug or an 85 sq. ft. leg o’ mutton
sail on her extendable aluminum and bamboo mast.
During the
winter of 2007-2008, after discussing participating in the
·
An
all Styrofoam, fiberglass covered bottom;
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A
roll-up cuddy cabin made from polytarp and sail window material;
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Add-on exterior Styrofoam panels to make the boat class
legal.
This last
add-on feature led my 6 year-old grandson to dub Webfoot hull # 199 the “Transformer
Boat”, after his favorite movie at that time.
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Webfoot concept |
Initial drawing and cardboard
mockup |
Bottom, showing extensions for
mounting sides to make the boat class legal |
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Webfoot
goes 3-D. Assigned hull # 199. Note add-on sides |
Interior completed. Weight 54 lbs. |
Webfoot awaits
float tests on |
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Canopy extended |
Wind pushes the lightweight Webfoot along at a comfortable pace.
Canopy acts like a small spinnaker downwind. |
This is the only picture I could
find of Webfoot under sail with her
sides on. The sail shown here was only 34 sq. ft. but pushed the boat along
nicely. |
Webfoot was completed
early in the summer of 2008 just in time for the first Hoosier Regatta.
However, no one was available to sail her in the race itself. She was sold in the fall of 2008 shortly before we moved to
With Webfoot I began
pushing the envelope on light weight hulls and cabin structure. I had used the
Styrofoam bottom previously in a 4’ x 8’ scow that was one of
five boats in the Hot Tub series I
had built. (See this account at http://www.polysail.com/boatnote.htm
) Boats of this size with a 2” Styrofoam bottom float high even when loaded and
will continue to float even with a substantial hole in the bottom. However, the
bottoms are easily damaged and are not easily shaped
to the extreme stern rocker of the PDRacer. The flat
run of the Hot Tub scows, on the
other hand, are more suited for the lightweight foam bottoms. Although Webfoot’s hull was lightweight, the
aluminum mast and wood kickup rudder and leeboard
added considerable weight to the structure. All would need to be redesigned for the Z-PDR.
In
designing Webfoot’s canopy/cabin, I was faced with the question of how to support the structure
without much weight. I solved that problem by incorporating two mahogany lathe
arches on either side of the boat. These arches, in turn, supported two
crosspieces and the polytarp canopy. Each arch was made up
of two 3/16” thick x 2” wide lathing strips that were glued together while arched. The
resulting arches were incredibly strong for their weight and would support the
entire hull when turned upside down. I could also lift the boat by
grasping the extended handles on one of the cross pieces.
The strength and rigidity the arches added to this boat led me to slightly arch
the deck of the Z-PDR both bow to stern and gunwale to
gunwale. Those arches helped solve one of the primary problems with the
rectangular structures of the PDRacers—making the
hull rigid.
Other
features of Webfoot that found their
way into the Z-PDR design were the low freeboard and extended bow concept. On Webfoot the bow transom is extended
above the deck by about 5” and supported on either side by pieces that were
left over from cutting the bow rocker from the 1” x 8” x 8’ cedar board that
forms the bottom chine. On the Z-PDR, instead of being in line with the sides,
these pieces were angled inward toward the bow, to both support the bow transom
extension and to support the mast partner. (See the photos below.)
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Diagram shows how the piece removed
from the frame to form the bow rocker was reused to
support the bow transom. |
Angling these bow support pieces
across the deck helps strengthen the boat’s structure. |
One of the new
features of the Z-PDR is a kick-up rudder that is both attractive and
functional. The case and tiller are one piece and designed so that the outline
continues the rocker, then curves back to form the tiller. A single bolt holds
the rudder in place in the case, and a single length of shock cord holds the
rudder in the down position or, when the rudder is lifted
slightly, elevates the rudder high out of the water. Tightening the wing nut
pinches the sides of the case together and holds the rudder firmly in place.
This rudder case is a much more pleasing and functional design than I have seen
on most small boats, and it particularly suits the low
profile of the Z-PDR.
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Rudder in the up position |
Rudder in the down position |
Case fitted to the stern transom |
I designed
Z to be a racing PDR, so the cockpit is bare bones and the ride will probably
be wet. I coated the floor in the stern half with a sand
finish paint for traction when moving from side deck to side deck. It is intended to be a “sit on” hull, not a “sit in” hull. A
hiking plank across the decks is not out of the question.
To optimize
her for racing, Z-PDR will have multiple sail, mast, and leeboard options.
Currently, I have four sail options: A 58 sq. ft. battened sailboard-type sail,
a 65 sq. ft. leg o’ mutton, an 85 sq. ft. leg o’ mutton, and a 100 sq. ft. high
aspect balanced lug sail. Each sail has its own mast
requirements, but by using a sectional mast, the mast length can
be extended from 15’ to 18’ 6”. The basic 15’ mast has two 4’ aluminum
sections and one 8’ bamboo section. This mast weighs in at
just over 7 lb. and will float. This mast can be used
for three of the four sails. If all goes as planned, only the 85 sq. ft. leg o’
mutton with its 17’ + luff will require the additional 4’ aluminum extension.
Four
leeboards may also be available for the Z-PDR. One of the larger ones will have
to be used on Wild
Duck, but the others can be used at will. Three of the four boards are
asymmetrical, while one is symmetrical and weighted. “Fat Bastard” is a short,
nearly square board that will put over 440 sq. inches down in the water with a
total length of only about three feet. On the other hand, the Big A… asymetrical Board is nearly as
tall as I am, but with its hollow core is very lightweight. One thing that hasn’t changed much is my preference for a leeboard over a
dagger board or center board. Once you build a trunk, it’s
not easy to change boards except to make one longer or shorter.
Leeboard selection for the Z. “Fat
Bastard” is the unpainted cedar board with the slot.
The Z-PDR awaits further testing at the Worlds in October. Skids and a
seat might be in her future if she fails to perform as a racing PDR.
November 2009 Update
The 2009
World Championship race at
On Monday,
October 5, my son and I trailered the Z-PDR out to
Tuesday,
Wednesday, and even part of Thursday morning were given over to repairs on both
boats instead of beginning the loading process. I added two skids, repaired the
hull, and epoxied the boom back together on the
Z-PDR. Wild Duck got some repairs to
her mast steps, gunwales, and stern, as well as some touch ups to the paint
job. As a result, I arrived at the campground at
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Rigging Wild Duck. On the left is John Wright’s lightweight
PDR with the oval sail. The Z-PDR is in the middle. (Tim Cleary Photo) |
Ryan
launches for the start of race #1. The starting buoy and boat can be seen in the background. (This photo and all the
following photos in this table courtesy of Ruth Leber) |
Ryan leads
a pack off the line in race #1. Notice the variety of sail types. |
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Wild Duck was performing well downwind, but
I had already lost a half lap to the Z-PDR and the Bloody Splinter in the background |
Ryan leads
Australian legend and designer of the OZ PDRs
Michael Storer on a run downwind. Eventual winner
Shawn Payment is in the red boat in the background. |
Ryan pulls
the Z ashore after an exhausting day of three races. |
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Here’s a good look at the 58 sq. ft.
sailboard-type sail with its sprit boom and small sprit spar. Ryan need to be
forward a bit to balance the Z |
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In the end,
the Z-PDR probably did about as well as could be expected
with so little testing. Since we had only successfully tested one sail, we
decided to use the small 58 sq. ft. sail for the races. A sail of this size was
a decided handicap against many of the sails that approached 90 sq. ft., but
the sail, design, and sailing skills of my son held up well against the
competition, placing 4th against 13 other boats. Ryan might have placed higher still,
if I hadn’t asked him to help me out of a bad
anchorage at the start of the third race. Even though he ran back to launch his
boat, he was unable to get to the starting line in time for the horn.
Consequently, the Z-PDR started race three at the back of the pack and never
fully recovered since that race was only one lap. Wild Duck, on the other hand, was a disappointment, finishing 10th
overall. As a result of a misplaced board, turns invariably ended with the boat in irons, and her 104 sq. ft. of
sail area could not make up for that problem on fast downwind runs.
Further testing
of the Z-PDR will come during the winter months here in
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This page
updated on 11/15/2009