IT’S
ALMOST EXACTLY 100 years since one of the most famous American small-boat architects
designed and built a wooden boat called Cabrilla. William Atkin and his boyhood
friend Cottrell Wheeler were the owners of a small boatyard on Long Island, New
York, and Cabrilla was the largest boat
they built there. She was a high-speed express cruiser, 115 feet in overall
length.
But
one of the most interesting things about her was the fact that young Atkin and
Wheeler themselves designed the twin V-8 gasoline engines that powered her. Not
only that: they built the engines, too, and installed them of course.
Atkin
said later in his book Of Yachts and Men: “Reviewing those days . . . I am astonished
at the work we undertook and produced. The design work on Cabrilla was no small item.” This, naturally, was long before the
days of computers, or even calculators, and all the work was done with pencil,
paper, drafting ink, and the human brain.
Atkin
described those engines as “big fellows of more than usual interest.” Each was
of V-type with eight cylinders. The cylinder bore was 8 inches and the stroke
14 inches. Each bank of four cylinders was cast en bloc and, to insure perfectly even cylinder walls, was cast
without the water-cooling jackets; the jackets were fitted to the cylinder
blocks after all the machine work was completed.
In
his book Atkin says: “The crankshaft was a steel casting and turned on
Hess-Bright ball bearings, three bearings to each engine. To give some idea of
the size of the crankshaft: the races of the bearings ran on balls having a
diameter of 2 3/4 inches. The inlet and exhaust valve sets were made of heat-treated
steel and were removable. The exhaust-valve stems were cooled with sodium. All
the reciprocating valves were closed by positive cams rather than by
compression springs. The crankcase was of skeleton form, cast of vanadium
bronze and had 1/16th-inch-thick Tobin bronze plates to cover the openings.”
Atkin
used outside contractors to manufacture several parts of the engine to his
designs, but hundreds of other parts were made and assembled in his own
boatyard basement.
“Yes,
shipmates, Cabrilla’s engines were
big fellows,” Atkin reflects, “and when, in these later years, Cottrell and I
contemplate the fading past, we marvel at our youthful courage in tackling this
job, which then seemed very simple, but which if attempted now would embarrass
the engineering department of a large corporation.
“Cottrell
designed all the mechanical and electric fittings for the hull, the disk
clutches and reverse gears, and supervised their construction. The design of
the engines was my contribution to the work then in hand. All this we
accomplished within nine months and without the assistance of draftsmen or
additional help.
“Fortunately,
Cabrilla was designed before the days
of expeditors, industrial efficiency, inspectors, personnel managers, safety
engineers and all the other complicated and expensive claptrap of present-day
production confusion. If we had had the fellowship of today’s industrial
top-heaviness and discord, the yacht might never have been launched at all.”
Today’s Thought
Often ornateness goes with greatness;
Oftener felicity comes of simplicity.
William
Watson, Art Maxims
Tailpiece
“Man,
I never realized how short of living space the world has become.”
“What
makes you say that?”
“Well,
I came home early last evening and found a strange man living in my wife’s
wardrobe.”
(Drop
by every Monday, Wednesday, Friday for a new Mainly about Boats column.)
"The exhaust-valve stems were cooled with sodium."
ReplyDeleteMethinks these fellows could have used at least a *little* help from a safety engineer.
https://youtu.be/khJal_j7jpY
ReplyDeleteSafety engineer? Exhaust valve stems filled with a liquid sodium solution was a relatively common technique of creating a heat path to keep the valve face cool, allowing you to run higher compression ratios and thus higher exhaust gas temperatures. (In all, probably far less hazardous to machine/produce than melting lead for keels for Gossake.)Certainly far less dangerous to the public at large than the leaded fuels which served essentially the same function...
ReplyDelete