GB Aleutian 53RP
he bow of the Grand Banks 53 Aleutian Raised
Pilothouse cleaved the oncoming wave cleanly,
dipped slightly on the steep backside as the powerful
middle sections of the hull moved swiftly through it,
and exited cleanly with little or no roll as the flatter
after sections and wide chines aft stabilized our
potential for roll. When a strong southeast wind meets
a fast-moving ebb tide outside the Port Canaveral inlet,
you can bet money that the ride heading out or in will
be interesting. And the conditions within the inlet itself
will be challenging, stacked up waves you approach
with one hand for the throttle, to quickly slow and
keep from stuffing the nose into an oncoming wave,
and with one hand for the wheel, to turn quickly just in
case an approaching boat loses control and veers into
your path.
Outside, the 5-foot waves were more regularly
shaped, although the 20-plus-knot winds frequently
pushed them together, much closer than you expect
at times. I was attacking the wave fronts at a moderate
angle, then steering for better control on the far side,
and the 53RP responded very quickly to my course
changes. Turns to head down wave were quick,
positive, and surprisingly stable during the time spent
in the trough, and just for a moment I wondered if this
boat was equipped with the optional Wesmar RS700
stabilizers I’d noted in the options list.
“No, they’re not on this boat,” came the reply to my
question, finally asked aloud. The speaker was Earl
Alfaro, Grand Banks’ in-house designer. Alfaro led the
GB design team effort on the 53RP project, and you
could tell he was happy with the way the boat was
handling this nasty stuff. So was I, come to think of it.
Lesser boats might have wallowed and slammed their
way through challenging conditions like this, but the
solid feel and nimble handling made this test ride a
confidence-building exercise. The same can be said for
our ride down wave, as I throttled back to keep pace
with the conditions, and steered lightly to let the hull
form and molded keel track precisely where I wanted
to be. We did take a little spray on the windows, but the
majority of the water was cast well out and away from
the hull, a dry-running boat if there ever was one.
From its classic, raised pilothouse profile to its
excellent seakeeping qualities and outstanding
performance, the 53RP was everything I expected it to
be. The ride was quiet—I recorded 68dBA at 11 knots,
both at the helm and in the main saloon, and 70dBA
on the accommodations deck level. In smoother water,
we achieved 24-knot speeds at half load with optional
twin 715hp Cat C12 ACERT diesels turning 2300
rpm. According to Grand Banks figures, range for the
big Cats at high cruise, or 18. 4 knots at 2000 rpm, is
approximately 347nm, which rises to 636nm if you pull
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the throttles back to 8. 2 knots. If extended cruising is
one of your goals, and you can accept a slightly slower
progress, consider the standard engines, a pair of 600hp
Cummins QSC 8.3s, which top out at 20. 1 knots at
3000 rpm, with a high cruise of 15.82 knots at 2600 rpm
for a 320nm range, and a low cruise speed of 8 knots
and a range of 1,000nm. Range calculations provided by
Grand Banks are based on total fuel consumption, that
is, main engine and genset together, up to 90 percent of
total fuel capacity, with 10 percent in reserve. And there
is an optional pair of twin 715hp Cummins QSM 11s to
consider as well.
THE HULL SHAPE
The 53RP has a modified deep-V hull that, like
the original 64 and 72 Aleutian hulls designed by
Tom Fexas, has the ability to cruise efficiently at
displacement speeds and still get up on top of the
water for higher speeds. “I had some personal history
with those boats, having worked in the offices of
Tom Fexas when he designed that hull,” Alfaro said.
“They were well regarded, but there’s always room
for improvement. We wanted to improve dryness,
and handling was a major consideration because we
also knew that the engines offered were getting larger.
From the design brief, we knew that the boat had to
perform between 20 and 25 knots, which meant that
the underbody had to be a semi-planing shape.”
Unlike all the other Aleutian designs, the 53RP has
its engines well aft, close coupled to ZF V-drives. To
support that weight aft, Alfaro and his team had to
provide a lifting surface aft. “This boat has a constant
deadrise for the last one-third of the running surface
where the beam is also the widest, not only to promote
planing, but also to add sufficient buoyancy to support
the weight of the engines, which were planned to be
farther aft than was traditional.”
As you go forward from the stern, the deadrise
at transom is 17. 8 degrees, warping to 23. 3 degrees
amidships, the high-pressure zone that will take the
brunt of wave impact. The sharper forward shape
dictates how well the bow will carve its way through
a wave, while the still-sharp midship section helps
mitigate pounding, and the flatter sections aft add
stability. “Deadrise was critical, but so was the need
for an efficient keel to improve tracking,” Alfaro said.
“We incorporated an integral keel having a wine-glass
shaped section in body plan, foil shaped to promote
laminar flow and minimize drag.”
The deepest draft for the keel is at trailing edge,
while the greatest cross section is located amidships.
The shape gradually tapers, blending into the stem
slightly ahead of the middle third of the hull. Like every
keel, it adds protection for the running gear, but with
