| A few years ago my wife asked me
to name my favourite boat. If I had thought about the question
at all, it would have been almost impossible to answer, because
there are so many designs which have appealed to me over the years.
But on that occasion I gave her an answer based on gut-reaction,
and that answer was, “Hesper”.
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Hesper Lines
American Small Sailing Craft Howard I. Chapelle |
Hesper (the evening star) was a Boston pilot schooner designed
by the great Dennison J. Lawlor, and built in 1884. She was 102
feet over all, and had a beam of 23 feet, and in the words of
the scholar Howard I. Chapelle her, “..speed and weatherliness
were phenomenal.”. I’ve always been attracted to the
looks of the schooner rig, but what drew me so strongly to Hesper
was her hull shape - the extreme fineness of her entry and a sharp,
hollow bow. To top it all off, she had a plumb (upright) stem
which gives an impression of great power. I guess that when I
specified Hesper as being my favourite, I was really just saying
that I like the lines of many of the pilot schooners and Gloucester
fishing schooners, and Hesper is a prime representative.
I haven’t worked out whether people like boats of a certain
shape because of having studied lines on paper and in the flesh,
or whether there is something deep within us which is drawn to
particular shapes. What I do know is that while we need to learn
from others, it is critical for each of us to trust our own sense
of proportion and judgment when choosing a design. In other words,
don’t think too deeply when making a design choice –
follow your instincts.
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Periwinkle |
Relying on instinct became very important to me when I was approached
by John Shrapnel in late 2007. John had drawn up a short-list
of designs for his next boat, and kindly invited me to put up
a competing proposal of my own. It was an intimidating offer,
because the other boats on John’s list were well-known designs
from established designers. Relatively speaking, my work was an
unknown quantity.
John had been spending a lot of time sailing Paul Hernes’
boat – in fact, Paul was having difficulty prying John’s
hand off the tiller long enough to have a go himself! That boat
was the first to be built to my Phoenix III design, and Paul had
put a lot of work into building and testing her. When John gave
me the opportunity to submit a competing proposal for his list
of designs he said three things: -
• she should look similar to Phoenix III;
• she should be two feet longer than Phoenix III, so that
he could always beat Paul;
• she should have a Cat-Ketch rig.
The first two requirements were easy enough to meet, but the
last one caused me some concern. John is a speed-demon, and I
knew that he wanted to go fast – but I also knew that the
Cat-Ketch (or Periauger) rig is not the fastest system for getting
a boat up to windward. I began to have visions of Paul’s
smiling face as he crossed the line in front of this imaginary
big boat. However, I decided to give it a go just to see what
eventuated on paper.
Now, when designing a small boat, internal layout is very important
to the success of the resulting craft. I guess that is the case
in big boats as well, but dinghies have such limited volume to
start off with, that every dimension must be carefully considered
in relation to the human form. When I started the initial sketching
of a cat-ketch rig for the new boat, it became apparent that the
location of the masts would allow a particularly good seating
arrangement for a cruising dinghy, and more importantly, would
make possible a really large dry-stowage/buoyancy compartment.
I was beginning to warm to the two-masted rig.
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Periwinkle Lines |
However, I was still concerned about making the boat fast enough
for exciting sailing. The influence of Hesper and her sisters
is never far below the surface of my pool of thoughts, and in
this new design I was able to bring at least some of those visions
to life on paper. The principal dimensions I had chosen were 17ft
x 5ft (5.182m x 1.524m) giving a length-to-breadth ratio of 3.4:1
overall and nearly 3.8:1 using waterline measurements. This is
fairly lean for a sailing dinghy, and allowed me to draw a bow
with hollow waterlines and a fine entry angle. The centre-of-buoyancy
was well aft at 58% of the overall length, but that suited my
purpose as I knew that people tend to sit too far back in a dinghy.
The numbers and the shape indicated a fast hull for a cruising
dinghy, and to ensure there would be enough horsepower, I put
155 sq.ft.(14.5sq.m)of sail into the rig. Both of the sails are
balanced lugs, because of that rig’s simplicity, good reefing
properties, and short masts. Being spread out along the length
of the boat, this rig has a low combined centre-of-area, meaning
that for a given sail area, the heeling moment is minimised –
a happy situation for this slippery vessel.
The resulting numbers are as follows: -
• Displacement/Length Ratio - 92 (the range
is 50 to 380+, with 92 being in the middle of the 50 – 120
‘Ultralight’ range). This factor is a measure of distribution
of volume over a longer waterline;
• Sail Area/Displacement Ratio - 25 This
figure was obtained by using the full area of the main plus half
the area of the mizzen (Standard procedure with ketches) and puts
her in ‘Very-High-Performance-Racers’ category. This
figure is really a measure of her strong-wind performance potential.
For light winds we need to look at Sail Area/Wetted Surface Ratio.
• Sail Area/Wetted Surface Ratio - 2.8
(using only half of the mizzen area in the calculation) Anything
greater than 2.6 indicates a very high performance potential in
ghosting conditions.
Periwinkle (as the design was now christened) was given the go-ahead
by the very brave John, and was built using the glued-lapstrake
(clinker) method. In order to keep building hours down, I designed
her with only five planks of plywood per side, and included frames
and bulkheads in the mold set-up. This saved time and materials
when building the mold. Planking was from 9mm marine ply, and
the deck was made of 6mm marine ply. Natural timber components
like the keel, stem, floor timbers, gunwales and bed logs were
made from Hoop Pine, Oregon, Victorian Mountain Ash, and Silver
Quandong. All structural gluing was carried out using West System®
Brand epoxy products, and metal fastenings were silicon bronze.
Coatings came from Norglass in Sydney.
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Perwinkle under sail |
Since launching day in late November 2008, Periwinkle has been
sailed frequently by John Shrapnel and many friends. Minor rig
tweaking continues, but I’m relieved to say that she has
proved to be everything that we hoped. Being light and lean, she
benefits from early reefing. In the event of a capsize, the boat
sits reliably head-to-wind with the mizzen sheeted in firmly,
while a crew member bails from the aft thwart (seat). The big
centreline aft-deck hatch remains above the capsized waterline
so that the compartment is protected from flooding even if the
hatch cover is left off.
Included in the design is a third mast location which allows
the boat to be sailed with only a single sail if conditions are
tough and the crew light. This mast location has been tested -
at various times using the main sail, and at others the mizzen.
In either case, the helm balance is good and the boat is easily
driven.
I know that in this life I will never set eyes on Hesper, but
the images I have of Periwinkle cutting through a chop give me
a hint of how she and her sisters must have appeared so many years
ago.
You can see plenty more photos of Periwinkle by going to my website
www.baysidewoodenboats.com.au
and clicking on the three buttons labeled “Periwinkle Photos”
(1, 2, and 3). Each of the three pages contains sixty or so expandable
thumbnails of building and sailing.
Ross Lillistone
Wooden Boat Design
***** |
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