Rare picture:
T Harrison ButlerNo racer, but she was a solid pocket cruiser,
and she had that balanced shelf
THEO RYET
homas Harrison Butler published a design
he called the ‘Zyklon’ in the July 1937
edition of Yachting Monthly. It was, he
explained, an improved version of his 1919
‘Cyclone’ design, which he had recently discovered
had (horror of horrors) a ‘crossed shelf’. Harrison
Butler had lately become a confi rmed believer in the
Metacentric Shelf theory and was discovering that
previously blameless earlier designs of his, subjected
to this analysis, failed a critical test. As he said, the
owners of the various Cyclones that had been built
(unaware they were sailing such degenerate craft)
reported all was well, that they were very well behaved
and nicely balanced; but with all the fervour of a convert
Harrison Butler was determined that this could not really
be the case, and a modifi ed design with what was termed
a ‘balanced shelf’ was needed. A second motive, and one
which has stood the test of time rather better, was “to
design the cheapest form of yacht”. The Z4s were the
production version of the Zyklon; they are pretty well
identical in all signifi cant respects although the Z4 is
usually quoted at 21ft 9in LOA. The “4” in “Z4” is a
reference to their Thames tonnage.
A true ‘pocket cruiser’ is a tricky circle to square for
a designer but Harrison Butler had had a lot of
experience by the late 1930s; his fi rst published designs
were for a 3.8 tonne 20ft LWL cruiser in 1909, and the
large majority of his designs were similar in terms of size.
His aim, as his daughter described, was to design “family
boats that would be easy on the helm, seakindly and
seaworthy, have a reasonable turn of speed and be
effi cient, comfortable and good-looking”; and to many
that is epitomised in the Z4.
The numbers tell their own story. Her displacement/
length ratio is 481, which places her well into the ‘very
heavy’ category; even allowing for her intended role, this
is signifi cant; the weight contributes to her manners at
sea, but it also puts the “reasonable turn of speed” into
context. Her sail area/displacement ratio is also rightdown at only 117; with the best will in the world, this
is stately rather than exciting territory. To put the
numbers into context, Folkboats (that came along
only a couple of years later) have basically the same
draught and overall beam, a few inches more on the
waterline and exactly the same sail area; but weighing
in at around 2 tonnes their ratios are 254 and 168
respectively. You are unlikely to see a Z4 winning the
Round the Island Race any time soon, but accept the
Z4 for what it is, an old-school heavy cruising boat,
and things make a bit more sense.
Harrison Butler, ever the pragmatist, very sensibly
included a 4hp motor installation in the design, but even
so in 1937 he said he had an estimate to build one for
£220. By the time O M Watts were marketing the boats
in 1938 (built by Alfred Lockhart Marine of Brentford)
the price was up to £297; still good value when a 6mR
from a reputable builder would be over £700, and it is
said that over 50 were built in the fi rst year. This was a
sturdy little yacht that could go pretty well anywhere,
slowly it is true (with a 19ft waterline these things are all
relative) but safely. Headroom in the original version was
only about 4ft 6in and some later builds had their
topsides raised to help in this regard, but they all have a
handsome charm and avoid boxiness.
It’s a simple hull design, if refi ned by Harrison Butler’s
extensive experience. The beam, at 7ft 2in, gives her
accommodation for two; and although carrying it to the
waterline helps with her initial stability, it will do little
for her windward ability. With an iron keel of a tonne
the ballast ratio is 30 per cent, low for the size and type
of craft, but they have a reputation as sound sea-boats
and with the modest sail plan stability at large angles of
heel is rarely tested. The buttocks and waterlines are
nicely controlled given the volume they enclose, and the
sections are similarly an object lesson in moderation. The
Z4 is then the Austin 7 of the classic fl eet; unpretentious,
a little slow perhaps but soundly built and capable, and
much loved for the freedom it has always offered.ZYKLON Z4
T HARRISON BUTLER
CLASSIC DESIGNS