The following article appeared in the April 2000 issue of
Powerboat Magazine
[2000
Performance Reports]
DONZI
28ZX
Call it a big sport boat. Call
it a small offshore boat. Either
way, the twin-engine Donzi 28ZX is a
well-built wonder.
Story by
staff
In the 28' range, the dividing
line between a sport boat and an
offshore boat is, largely, where a
given manufacturer draws it. One
manufacturer's large sport model is
another builder's small offshore
offering. The most likely
determinant is where a particular
boat falls in a particular company's
line.
Donzi tags its 28ZX a "sport
boat." We wouldn't argue with
the folks at the Sarasota, Fla.,
company. But after spending some
time in the twin-engine,
27'7"-long, 8'6"-wide boat
at our Performance Trials in
Sarasota, Fla., we'd prefer to call
it a sport boat with an offshore
attitude.
The 28ZX is available with a
single engine-per special order-or
twins. (For single-engine model
pricing, buyers need to contact
Donzi.) The base model with a pair
of MerCruiser 5.7L motors is
$90,267. For our tests, the
manufacturer outfitted the boat with
two MerCruiser 350 Magnum MPI
motors, the biggest twin-engine
package offered, and more that upped
the price to $112,650.
Performance
The sport boat's 22-degree transom
deadrise "Z-Tech" hull
incorporated, two steps, two strakes
in each of the boat's three running
surfaces and a delta-pad keel.
Though evenly spaced on each running
surface, each pair of strakes was
offset from surface to surface. As
for the boat's chine, it was about 4
inches wide and flat.
The 600-hp from the boat's two
small-blocks was channeled into
Bravo One drives with 1.5:1 gears
and Mirage Plus 14 5/8" x
23" three-blade stainless-steel
propellers.
On sticky Sarasota Bay glass and
high humidity-hardly conducive for
speed runs-the 28ZX ran a solid 71.6
mph at 5250 rpm. Both standing-start
and mid-range acceleration were
strong. Time to plane was 5.7
seconds with the Bennett trim tabs
deployed, 6.4 seconds with them up.
Twenty seconds was all it took for
the boat to reach 66 mph.
In the mid-range, the 28ZX popped
from 30 to 50 mph in 5.4 seconds and
from 40 to 60 mph in 7.3 seconds.
Showing the limitations of the
supplied small-block power, the boat
took 16.9 seconds to run from 40 to
70 mph.
While the glassy conditions
weren't ideal, they were just dandy
when it came to agility drills.
Glassy water has a way of revealing
handling flaws-especially if a boat
is going to catch, hook or hop. The
28ZX did none of those evil things.
The boat was decidedly well-mannered
and stable in slalom turns at 30, 40
and 50 mph and carved its way
through decreasing-radius circles at
cruising and full speeds.
Without question, the twin
engines helped the 28ZX in terms of
tracking. Speeding up or slowing
down, the boat never wandered from
course. The twin powerplants made
straight-line idling, as well as
docking, a breeze.
The 28ZX felt so solid in
Sarasota Bay that we couldn't wait
to take it into the Gulf of Mexico.
And in 2- to 4-foot seas, the boat
was rock solid. It landed softly
after being launched without so much
as a rattle or squeak. The
forgiving-yet- solid ride made for
comfortable head-on running, as well
as strong performance in following
and quartering seas.
From
left:
Although Donzi calls the
28ZX a sport boat, its looks
screamed offshore racer.
From the dash with Mercury
shifter and throttles and
large Gaffrig gauges to the
stylish cabin with a V-berth
and lounges to the
rough-and-ready cockpit with
stand-up bolsters, we knew
the 28ZX was ready for the
big stuff. You'd better hold
on.
Workmanship When it comes to paint work, no
production-boat manufacturer does it
better than Donzi. To give the
boat's black, red and gray color
scheme atop premium gelcoat extra
shine and luster, the manufacturer
used Clearcote. The job of
protecting the boat's exterior fell
to a tough plastic rubrail with a
rubber insert.
The stringers and transom for the
28ZX were made from polyurethane
foam-no wood was used in the boat's
construction. Like its smaller 26ZX
sibling, Powerboat's 1999 Sport Boat
of the Year, the boat was hand-laid
with bi- and triaxial fiberglass and
vinylester resin. In addition to
coring the hullsides with Divinycell,
the manufacturer vacuum-bagged the
transom. Plexus adhesive was used to
bond the hull, deck and liner.
Especially noteworthy in the
boat's hardware was its "venturi"
Plexiglaswindshield, which actually
deflected wind. More standard fare
included a nav night, an Accon
Pop-Up cleat and an anchor locker on
the nose, another Accon cleat on
each side of the windscreen plus two
more all the way aft, a sliding
ladder on the integrated swim
platform and a grab handle on the
transom.
Twin-engine installations in
28-footers can give riggers fits;
after all, two motors and all their
accompanying hardware, hoses, cables
and wires must fit into tight
quarters. Under the
screw-jack-raised engine hatch for
the 28ZX, we found that two engines
and all their accouterments can
indeed find a neat and happy home in
a boat this size.
Each small-block motor was
installed on aluminum L-angles with
gussets and heavy-duty brackets that
were thru-bolted to the stringers
and the standard transom assemblies.
Color-matched diamond plate was
installed on the sides of each
motor-the screw jack was secured
between them. All wire looms were
run parallel, and the
stainless-steel cushion clamps
supporting them were aligned. Also
aligned symmetrically, one on the
outside of each motor, were the trim
pumps for the drive. Both
custom-fabricated battery boxes were
color-matched to the compartment's
gray and red interior. Combined with
mirrors on the underside of the
engine hatch, the overall neatness
of the rigging created a look and
feel of "extra" space,
where no such space existed.
Interior
Behind an acrylic door that slid in
upper and lower aluminum tracks, the
cabin of the 28ZX was simple yet
functional, even elegant. In
addition to a large V-berth and
facing lounges, there was a small
galley area with a sink and a small
cooler. Under the V-berth was a
Porta Potti.
Of course, given the boat's
performance, the cockpit was the
place to be. Both the co-pilot and
driver were supplied with manual
drop-out bolsters, which Donzi
manufactures. On the back of each
bolster was a powder-painted grab
handle for use for outside
passengers on the four-person rear
bench.
At the helm station to starboard,
all the Gaffrig gauges were set in
red bezels. In addition to the array
of gauges, there was an Azimuth 1000
electronic compass and Gaffrig
mechanical trim indicators for the
drives and tabs.
The only somewhat surprising
omission we found at the helm was
that of a throttle-mounted
drive-trim button on the Mercury
throttles and shifters. Instead,
just ahead of those controls were
rocker switches for the drives and
tabs. We'd keep the rocker switches,
which were located conveniently
enough, but add
throttle-hand-mounted drive-trim
control. It just makes things
easier.
Overall
By any designation, the 28ZX is an
impeccably rigged, carefully
constructed performer. Call it what
you will-we'll just call it
outstanding.
Worth Noting
Think a twin-engine installation in
a 28-footer has to be tight or
cluttered? Think again-Donzi pulled
it off in the 28ZX in a manner that
puts most 38-footers to shame.
We felt no need to shy away from
the rough stuff offshore, thanks to
the solid construction and sure ride
of the 70-mph 28ZX. Best of all,
stability didn't come at the price
of agility.
TEST
RESULTS
Hull
Information
Deadrise at transom
22 degrees
Centerline
27'7"
Beam
8'6"
Hull weight
5,200 pounds
Pricing
Information
Base retail
$90,267
Price as tested
$112,650
Engine
& Propellers
Engines
MerCruiser 350 Magnum MPI
Cylinder type
V-8
Cubic-inch
displacement/horsepower
350/300
Lower-unit gear ratio
1.5:1
Propellers
Mercury Mirage Plus 14
5/8" x 23"
Standard
Equipment
Anchor locker, manual
bolsters, stainless-steel
hardware, windscreen,
compass, full Gaffrig
instrumentation with
color-matching bezels, Zero
Effort controls, CD stereo
with four speakers,
Plexiglass door, Porta Potti,
mirrored, electric engine
hatch, hydraulic steering,
recessed swim ladder,
external tie bar, dual-ram
trim tabs.
Options
on Test Boat
Upgrade to twin
MerCruiser 350 Magnum MPI
engines ($9,726), In Motion
paint ($4,714), Quick &
Quiet exhaust system
($3,100), mechanical trim
and drive indicators
($1,871), galley with sink
and cooler ($1,136), colored
diamond plate ($1,000), fire
extinguisher system ($329),
depthfinder ($307), hour
meter ($200).
[2000
Performance Reports]
