On quiet steps - Petestep
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Technik WasserSport 05/19
www.motorbootonline.de/boote/petestep-auf-leisen-stufen
1
STEP BY STEP
– On quiet steps
Ray Hunt and Dick Bertram have a safe place in the “Hall of Fame” of boatbuilding. When
in 1960 Dick Bertram's “Moppie” won the infamous Miami Nassau Ocean Power Boat Race
-
in a new record time, the new V-Shape hull design by design autodidact Ray Hunt heralded
a new era in the construction of rough water powerboats. The assertion that the development
of the planing hull has been going in the wrong direction for over 50 years almost sounds
like blasphemy and in any case not like typical Swedish understatement.
Text: Christian Schneider / Photos: Schneider / Petestep AB / Graphics: Petestep AB
Idea serve to stabilize the boat and
But this is exactly what the repel spray. “Wasted energy...” he
employees of a small Stockholm thought and thought about a
design office claim in their better solution that would recycle
video presentation. The Swedes, this energy and turn it into a
who are usually not accused of force that lifts and accelerates
exaggerating and boasting, have the boat.
been calling into question the The Swedes, who are usually not
“laws” of boatbuilding chiselled accused of exaggerating and
in wood, metal and GRP since boasting, have been calling into
2017 with the “Petstep-Hull”. question the “laws” of boat-
The idea was inspired by the building chiselled in wood,
Swedish businessman and metal and GRP since 2017 with
enthusiastic motorboat driver the “Petstep-Hull”. The idea was
Peter (Pete) Bjersten, who - inspired by the Swedish
noticed how much water is businessman and enthusiastic
displaced and thrown out by motorboat driver Peter (Pete)
the usual glide stringers, which Bjersten, who noticed how much
48
ACKERMANN
Yachthafenausrüstung e. K.
1 The new Silver Tiger is the second model astern and should lead away to the rear
of the shipyard with the new Petestep hull. via steps in the rear edge. This should lift
2 Sharp curve, stable position - even U-Turns the boat slightly and create a thrust effect.
from high speed the Silver Tigers complete Second: The frictional resistance should
with serenity. be reduced due to the smaller wetted area,
3 The racy Swedish HOC 33 P was one of because the boat only touches the water
the first projects to be realized. with the lower point of the keel V when
(Photo: Petestep AB)
Informationen und Datenblätter unter: www.ackermann-bootsstege.de
gliding.
Anfragen bitte an: ackermann-roebel@t-online.de Tel.: 039931/59761
Thirdly: Since Petestep hulls do not have
horizontal, flat surfaces that hit the water
Winterlagerstützen
2 when they are deployed and thereby
destroy energy, Petestep hulls should
generate much less noise from waves,
which considerably increases ride comfort.
In addition, the spray that is discharged
under the hull should provide a damping
effect and reduced friction when the hull
is inserted.
All in all, the Swedish company estimates
that the efficiency increases compared to a
conventionally designed V hull are in the Versorgungssäulen
order of about five percent for each of Fernablesung
online - Verwaltung
these points, which, when added together,
should result in up to 15 percent better
overall efficiency.
“But low fuel consumption is not the
biggest difference...” explains naval architect
and Petestep CEO Jonas Danielson during
the presentation of the new Silver Tiger,
one of the first boats to be equipped with
the new hull. "The first thing that is
noticed is the significantly softer behav-
3 iour of the hull in the wave and the fact Aluminiumschwimmstege
that the boats with Petestep hull are
water is displaced and thrown out by the significantly quieter. “You'll also be sur-
usual glide stringers, which serve to prised by the boat's great lateral stability,”
stabilize the boat and repel spray. “Wasted he promises before the first test run.
energy...” he thought and thought about a The measured data from the test runs
better solution that would recycle this with comparable boats confirm this. The
energy and turn it into a force that lifts engineers were able to determine up to 57
and accelerates the boat. percent lower G forces, which had an
The solution looks simple at first glance, effect on the crew when sailing in the
but Petestep engineers worked on it for wave, during comparative runs. On Aluminiumbrücken
several years to determine the optimal average, the peaks of the acceleration
course of the new hull steps. In the - forces in the wave are reduced by 30
patented Petestep hull, the conventional percent, says Danielson. But energy
glide stringers running parallel to the efficiency is not neglected either: Up to 35
keel direction are replaced by a series of percent less energy is to be required to
deflectors that rise from zero at the same drive the boat, which can lead to signifi-
angle as the waterline of the respective cantly lower fuel consumption and enable
boat in gliding motion from the lowest the use of smaller, cheaper engines.
point of the V-frame to the kink of the
keel in a slightly concave shape to a Practice ABI- Trailer
height of approx. 45 millimetres. This is Beside the Silver Raptor, the Tiger is
intended to reduce the drag in the water already the second model of the renowned
in three ways: Finnish series manufacturer, which is
equipped with the new hull. The robust
Theorie Daycruiser, which is alternatively avail-
First: Shape, size and direction of the able as a Bowrider, has a length of 6.06
deflectors should not lead away spray and metres, a width of 2.36 metres and an dry-
water to the side as before, but downwards weight of 1150 kilograms without engine
ASCOM boots- lift
49
Technik WasserSport 05/19
1
2
the water and moves forward
3
and backward exactly where it
should. Turning on the plate,
short stopping, with short thrust
ahead crisply just get the curve
in front of the jetty... all no issue
- good kitten, simply drives like
a good boat.
Outside on a course against it's
getting serious and the lever is
“lying on the table”. Punchy but
not rabiat pushes the 150er
Honda the Silver into the glide.
Actually she “slips” out of the
water. It takes three seconds
from a standstill with two people
The V-frame on the mirror coast off the Swedish Karlshamn
has a moderate rise of 19 builds up only a small bumpy
4
degrees. The new Silver is wave, while in some distance
powered by the manufacturer's to the land cover there is even
so-called Z-range, which is a short sea, which makes it
completely made of GRP, with possible to test the boat not
a Honda BF 150 with 150 hp, only under “laboratory
which has been approved by conditions”. The first “exer-
the shipyard for maximum cises” during manoeuvring do
power. not reveal any negative abnor-
A strong north-westerly wind malities. On the contrary: as
in the lee protection of the promised, the boat is stable in
5
6
50
1 Good to see: The discharge of the spume come on, there's something else ...
to the rear astern. Yep - 42 knots cracked! We remember:
There is no V8-Engine hanging, but
VOLT
2 The innovative hull design allows a smooth
ride at high speeds. E L E K T R O A N T R I E B E
an engine of the upper middle class
3 The deflectors direct the spray backwards with 150 HP at the rear! The boat
down under the fuselage and create a feels safe and controllable in every
lift-and-push effect. situation and is a lot of fun.
4 Comparison of measured values Standard
hull / Petestep hull of the forces acting on Conclusion
IHR MEHR?
the boat when it is being driven in the
.wave. (Graphic: Petestep AB) Perhaps it is presumptuous to attribute
The model illustrates the course and the
the “blame” for the excellent sailing
5 characteristics of this boat only to the
rise of the deflectors from the keel to the
JETZT
rear edge. new hull design - other designers and
The development of the Petestep hull was
engineers have certainly done a good
6 job here. Even a comparative evalu-
the subject of the master's thesis by
shipbuilding engineer and Petestep CEO ation would only be meaningful if we
Jonas Danielson. had two identical boats available, one
ELEKTRISIERENDE
with a conventional hull and one with
ANGEBOTE
a Petestep hull. Nevertheless: The new
Silver “Petestep” tiger could impress-
ively prove that the Petestep hull is
SICHERN!
more than just a step in the right
direction. It fulfilled all promises and
in some respects even exceeded
on board, as later measurements show. expectations and set new standards.
At 30 knots there is a nice cruising This includes the very quiet and soft
0
speed, the water rushes, the wind ride in the wave, the very high driving
whistles and...? Nothing else! Apart stability, as well as the high perform-
S p irit .210.19
from the sonorously humming Honda ance with a moderate engine.
einve s 4.-11.5
- no hitting, no rumbling, no rattling, Interested parties are therefore
K a u f o m 1.
no bobbing in the short wave or recommended to take a test drive. The im
Be ktionszeitra um
99 9 €) o
der
(sta tt
im A 849 €
swinging around the longitudinal axis boats are distributed in Germany by )
k ku ta tt 160 €
- the boat lies smoothly on the keel the company boat-solutions in Utting
za tis (s
edge and planes with a quiet and calm am Ammersee via a dealer network. Zusat a sc he gra )
ride over the water. It's hard to Each Petestep hull is developed exactly
u. A kku t
ta tt 149 €
Motor
- atis (s
describe, but it feels somehow for the intended purpose. The boats
tr ike r 4 gr
S
armin
“different” - extremely “light-footed” are simulated under different load
and casual as this boat lies on the conditions and speeds before construc- oder G
rudder, parries the wave and takes any tion and the final construction in
manoeuvre with sporty verve and yet order to enable a very high degree of
with great composure. Some trim on optimisation.
the engine, the speed still a little high Since 2017 several boats of different
and around with the wheel! The Tiger sizes have been built with Petstep
pulls with only little side inclination hulls. The company has patented this
despite high travel her curve tightly design principle and would like to
and more closely up to the rabiat cooperate with manufacturers and
driven U-turn, which I allow myself shipyards in the dissemination and
after a few attempts, now in the firm further development. Enquiries are Vergleichbarer Benzin-Motor 3 PS
confidence on the stable driving welcome. Eingangsleistung 1 kW
characteristics of the boat. Indeed,
Batteriekapazität 1018 Wh
I am surprised! With each round this
Nennspannung 40,7 V
cat of prey makes more fun, goes on
Gewicht (ohne Batterie) 10,6 kg
velvet paws into the glide and laces
with cat-like elegance in smooth silky Batteriegewicht 8,8 kg
run there, almost in order to make it’s Standschub 66 lbs
name honour. Ladezeit max. 6 h
The Honda roars with over 6000 tours Batterietyp Lithium-Polymer
and the Silver burns towards open Wasserdicht nach IP67, Batterie schwimmfähig
water. There is already some wave
here. Very finely trimmed the www.petestep.com
Bei allen teilnehmenden Händlern:
aggregate, there are the 41 - 41.5 ... www.boatsolutions.de/raptor-motorboot
www.epropulsion.de
www.motorbootonline.de/boote/petestep-auf-leisen-stufen 51
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