Ericus (Ricus) van
de Stadt designed
Black Soo in the
new marine
plywood62 CLASSIC BOAT APRIL 2016
A 29ft offshore racing yacht, lighter than a
dayboat built in 2016, and she could plane
THEO RYEB
lack Soo was built by R&W Clark of East
Cowes in 1957 for Michael Pruett. In period
she was described as a development of van
de Stadt’s Zeevalk (his fi rst design, of 1949)
and Fair Meg of 1955; but van de Stadt moved things
along a fair distance again with this radical design and
her near sister, Zeeslang. All of them were based
around hard-chine construction in plywood; the fi rst,
Zeevalk, was effectively an advertisement for van de
Stadt’s friend Kees Bruynzeel’s new marine plywood,
and she proved a weapon under the right conditions,
coming second in class to the overall winner Yeoman
in the 1951 Fastnet. The early post-war period was an
era of exciting and rapid developments in lightweight
design, with Laurent Giles producing Myth of Malham
and the remarkable Sopranino, and even though the
trend had slowed by the late 1950s, the attractions of the
type were by then well established. Zeeslang (design
number 58) was also for Bruynzeel, but Black Soo
(number 59) was destined for a British owner. She was
described as “the nearest thing to a planing boat in the
RORC fl eet”, and indeed with a good breeze on a deep
reach, given a helpful wave face (and despite her narrow
beam), she could be induced to plane, with some
remarkable claimed speeds resulting. Her total
displacement was about half the weight of just the ballast
keel of her contemporary Cohoe III, which was also 26ft
on the waterline and of “moderate displacement”. Even
today a 30ft yacht for offshore racing would rarely
displace as little as 1.6 tonnes; the modern J88 dayboat
at 29ft 3in LOA (8.90m) displaces 2.2 tonnes, which
puts the 59-year-old design of Black Soo into perspective.
Her cast iron hollow fi n keel with a swept tip bulb,
described in 1958 as at “the limit of narrowness”,
weighed 760kg, giving her a ballast ratio of nearly 48%.
It demanded clever design and no doubt a high level of
boatbuilding to keep her down to weight.
Notwithstanding that the hull was effectively comprised
of fl at panels, her fi ne scantlings would have needed a
careful touch. Thanks to her very narrow beam her
wetted surface area was minimal despite the immersed
chine, and she was very easily driven; even the mainsailfrom a 14ft dinghy that she took as a stormsail on the
Fastnet proved too large. Her dead straight sheerline
and fl at panels gave her appearance an angular
modernity, and her good rise of sheer forwards must
have helped prevent nose-diving as she ventured
offshore, but even so she must surely have provided
her crews with a wet ride. The relative lack of fl are in
the sections probably gave her a useful ability to ride
on the chine when heeled, using the immersed topside
area to resist leeway. The combination of fl at panels
and the hard chine gave her a hollow entry on the
waterline, but as Herreshoff’s Alerion and others
demonstrate, this is not necessarily a disadvantage.
There looks to be just enough angle on the forward
sections underwater to help avoid slamming when
upright, but as she heeled over that may not have been
true, and the qualities of Bruynzeel’s plywood must have
been tested at times.
In the original form there was ruthless elimination of
excess weight. This was a narrow boat, no question, and
had a very limited interior with, as some wit noted, “full
crawling headroom”. The four GRP Royal Cape One
Designs based on the same design had a nod to
convenience with a modestly raised doghouse at the aft
end, but the original Black Soo had a low coachroof
with transparent plastic panels. With a second tiller
extending into the aft end of the cabin, the helm could sit
below to steer and still see up to check sail trim.
She was tough; she sailed through a Force 8 gale in
the 1957 Fastnet that caused Bloodhound to heave-to
overnight and Drumbeat to retire after wrecking fi ve
winches. Ironically Black Soo then had to retire due to
electrical problems; an early example of a problem we
might consider a modern curse. Black Soo was based in
Ireland for many years from 1962, but as the doyen of
yachting correspondents Winkie Nixon noted, she
“eventually succumbed to the Irish weather which is
murder for even the fi nest plywood” and was broken up
sometime around 1999. Her near sister, Zeeslang, was
luckier; after racing in South Africa for 50 years she was
restored and is now a “cherished classic” in Switzerland,
exhibited at the Düsseldorf Boat Show in 2014.BLACK SOO
VAN de STADT
CLASSIC DESIGNS