Boat International US Edition - June 2018

provided the impetus. As early as 2001,

Kay had been in talks with Welbourn

about a new “unlimited” maxi yacht, and

after three years of design and tank-

testing the project had a complete

design that Kay describes as “pretty

cool.” Sadly, the project was halted when

the sponsor was taken over, but work on

the DSS foil did not stop. Heartened by

the good results from computer

simulations, Welbourn played around

with practical tests when time allowed,

trying out fixed foils on a variety of scale

models and full-sized sportsboats, as

well as more formal tank-testing at the

Wolfson Unit in Southampton, UK, and

at GKN in Cowes on the Isle of Wight.

“Not only did these prove that stability

and speed were significantly increased

by the foil,” explains Welbourn, “but they

also gave unexpected results. These

demonstrated a clear reduction in

pitching that made the yacht better

upwind in a choppy sea, while also

smoothing the airflow over the sails,

which made them more eicient. This

was our first serious glimpse of success

and enabled Gordon to persuade a client

to build the first Infiniti 37.”

This yacht proved the foil’s eiciency

beyond doubt but, as Welbourn explains,

“the foil needs to travel at a certain speed

through the water before it attains

maximum eiciency, and because of this

yacht’s midships, where her DSS foil case

would normally be fitted, is occupied by

her canting keel mechanism. So instead

of a single through-hull foil case that

would allow a foil to be deployed on either

side of the hull,Maverickhas two scimitar-

shaped foils that retract into sheaths

positioned in the bows of the yacht.

“While being slightly heavier than

a simple through-hull mechanism,” says

Kay, “this system brought another

unexpected benefit: when jibing in strong

winds – a nightmare scenario for most

sailors – both foils could be extended to

give her the reassuring stability of

a child’s bike with trainer wheels.”

Maverickis certainly fast and, despite

a handicap system that tries to level the

playing field for all competitors, she is a

regular race winner. But surely this is of

little interest to the owner of a bluewater

cruising superyacht? There is one person

who disagrees, and he is the experienced

owner of a string of significant cruising

sailers, the last of which wasCanova,

a Baltic 112. “Canovawas my fourth Baltic

and my first custom build,” he says, “and

she was specifically designed to make a

cruising circumnavigation with a

minimum number of in-port stopovers.

This meant that she had to be safe,

comfortable and perform well.”

The challenge to designers Judel/

Vrolijk was to provide sufficient fuel

capacity and storage to permit such

autonomy, while maintaining excellent

sailing performance. Launched in 2011,

Canovaproved pretty successful. “My

family and I made the cruise, and while we

never made the circumnavigation, she

performed magnificently on three

Atlantic crossings as well as the

intervening cruises.” But, he adds, “we

didn’t get it absolutely right as there are

always improvements to be made. We

could have done with more volume, and

then there was the diiculty of living for

days on end at a 22 to 24-degree angle of

heel. We found this especially tiring and

I wanted more comfort in my next boat.”

Canovawas sold in 2015 and research

into a larger yacht began almost

JUNE 2018 WWW.BOATINTERNATIONAL.COM

“Likeallradicalideas,it

needed a great deal of

expensive development”

it was sure to work even better on a larger,

faster boat.” That boat was to be Maverick,

designed to be the world’s fastest 45

footer, with a specific aim to win ofshore

races of 600 miles or more with a

Corinthian crew of just six. It was a tough

ask but one that Maverick has delivered

with some significant class victories and

second place overall in both the RORC

Middle Sea and Transatlantic races.

Maverick also demonstrates the

adaptability of the foil system, as the ILLUSTRATION: SON OF ALAN - FOLIO ART

● Sailing boat

equipped with

Dynamic

Stability

Systems

(DSS) foil

● Normal sailing boat

Pitching

reduced

• therefore
  smoother
  airflow

Forward force

increased

Heeling

force

Lift

Aero/hydrodynamically

shaped foil adds to

righting moment,

allowing lighter keel

Foil also provides

fore and aft stability,

reduces pitching and

makes airflow across

sails more ecient thus

giving improved drive

Lighter keel = lighter boat, which

means better acceleration

Sails drive

boat forward...

...but also

cause boat

to heel

As boat heels,

a very heavy

keel counteracts

heeling force

(righting moment)

Drag of hull

and keel

116