Vetus Hydraulic Thruster
A bow thruster delivers a side directional thrust force. In order to ensure the best performance under all sorts of weather and water conditions, the bow thruster should be able to provide a thrust force which is suitable, or rather: sufficient, for the boat in which it has been installed. The applied moment of the thrust force - which means to say: the position of the tunnel in the bow - is of prime importance for the bow thruster's efficiency. The further forward the bow thruster is positioned, the greater will be the efficiency.
Call Vetus Tech Support at 410 712 0740
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| | | | VETUS Hydraulic Bow Thruster 121 Lb Including Hydro Motor 3.5Kw, 4HP, BOW55HMD
Brand New with Factory Warranty | | VETUS Hydraulic Bow Thruster 1215 Lb Including Hydro Motor, 33Kw (44 HP), BOW550HMD
Brand New with Factory
Warranty
Ship only via Ground Freight Rate. No Flat Rate. | | | | | | VETUS Hydraulic Bow Thruster 200 Lb Including Hydro Motor 6.0Kw, 8HP, BOW95HMD
Brand New with Factory Warranty | | VETUS Hydraulic Bow Thruster 352 Lb Including Hydro Motor 9.5Kw, BOW160HMD
Brand New with Factory Warranty | | | | | | VETUS Hydraulic Bow Thruster 507 Lb Including Hydro Motor 12Kw, BOW230HMD
Brand New with Factory
Warranty
Ship only via Ground Freight Rate. No Flat Rate. | | VETUS Hydraulic Bow Thruster 662 Lb Including Hydro Motor 20 KW, 27HP, BOW310HMD
Brand New with Factory
Warranty
Ship only via Ground Freight Rate. No Flat Rate. | | | | | | VETUS Hydraulic Bow Thruster 905 Lb Including Hydro Motor 22Kw, 29HP, BOW410HMD
Brand New with Factory
Warranty
Ship only via Ground Freight Rate. No Flat Rate. | | VETUS Hydraulic Pump with 1.83 cubic inch with Cast Iron Body, Left Handed HT1016SD1
Brand New with Factory Warranty | | | | | | VETUS Hydraulic Pump with 1.83 cubic inch with Cast Iron Body, Right Handed HT1017SD1
Brand New with Factory Warranty | | VETUS Hydraulic Pump with 2.75 cubic inch with Cast Iron Body HT1015SD2
Brand New with Factory Warranty | | | | | | VETUS Hydraulic Pump with 2.75 cubic inch with Cast Iron Body, Left Handed HT1016SD2
Brand New with Factory Warranty | | VETUS Hydraulic Pump with 2.75 cubic inch with Cast Iron Body, Right Handed HT1017SD2
Brand New with Factory Warranty | | | | | | VETUS Hydraulic Pump with 4.57 cubic inch with Cast Iron Body, Left Handed HT1022SD
Brand New with Factory Warranty | | VETUS Hydraulic Pump with Aluminum Body, 2.75 cubic inch, Side Connection, Left Handed HT1016
Brand New with Factory Warranty | | | | | | VETUS Dual step load sensing device, incl. electrical connection box HT1012
Brand New with Factory Warranty | | VETUS Dual step solenoid control unit 24 V, for anchor windlass HT102312
Brand New with Factory Warranty | | | | | | VETUS Hydraulic Tank 18.5 Gallon (70 Liters) (Excluding Control Device) HT1010
Brand New with Factory Warranty | | VETUS Hydraulic Tank 34.3 Gallon (130 Liters) (Excluding Control Device) HT1010BS
Brand New with Factory
Warranty
Ship only via Ground Freight Rate. No Flat Rate. | | | | | | VETUS Manifold for additional control units HT1026
Brand New with Factory Warranty | | VETUS Single step load sensing device, incl. electrical connection box HT1011
Brand New with Factory Warranty | | | | | | VETUS Single step solenoid control unit 24 V, for anchor windlass HT102311
Brand New with Factory Warranty | | VETUS Solenoid control unit 24 V, for bow and stern thrusters HT1013
Brand New with Factory Warranty | | | | | | VETUS Solenoid control unit 24 V, for lowering mast or radar support HT1014
Brand New with Factory Warranty | | VETUS Solenoid control unit 24 V, for power steering system or autopilot HT1019
Brand New with Factory Warranty | | | | VETUS Solenoid control unit 24 V, for use with a set of stabilizers HT1024
Brand New with Factory Warranty | |
Selecting the correct Bow Thruster
A bow thruster delivers a side directional thrust force.
In order to ensure the best performance under all sorts of weather and water
conditions, the bow thruster should be able to provide a thrust force which
is suitable, or rather: sufficient, for the boat in which it has been
installed. The applied moment of the thrust force - which means to say: the
position of the tunnel in the bow - is of prime importance for the bow
thruster's efficiency. The further forward the bow thruster is positioned,
the greater will be the efficiency. |
The force applied by the wind onto the boat is determined by the factors:
wind speed, angle of wind attack and lateral wind draft area
of the boat.
- The Wind Pressure
When the wind speed increases, the wind pressure increases
quadraticallly!
For wind pressure 'P', the formula reads: P = 1/2p × V²
(l bf/sq.ft)
p (rho) represents the specific mass of air and 'V' stands
for the
velocity of the air in ft/s.
The table below will give you an impression of wind speeds and the
resulting wind pressures. It will not be possible to counter completely
the adverse effect of winds of 40 knots or more. But, in such cases, the
bow thruster will still "lend a strong helping hand".
- The Wind-Draft of the Boat
The forces applied by the wind onto the boat can be determined by
multiplying the wind pressure by the wind draft area. The wind draft area
is determined by the shape and the dimensions of the superstructure. Also
the wind angle is playing its part. The worst situation is created if the
wind is at 90 degrees to the boat. However, due to the shape of the
superstructure, which is mostly more or less streamlined, a reduction
factor may be applied to the wind draft area, before calculating the wind
pressure resulting from the wind speed. This reduction factor may
generally be set at 0.75.
- The Torque
The torque is determined by multiplying the wind force by the distance (A)
between the center of effort* of the wind and the center of rotation** of
the boat. Assuming that the wind force is amidships and assuming as well
that the boat will tend to turn at the transom, the torque, caused by the
wind force, is calculated by multiplying the wind force by half of the
boat's length.
* - Dependent upon the shape of the boat's superstructure, the
center of effort may be positioned more forward or more aft.
** - The center of rotation of the boat may be positioned more forward,
dependent upon the shape of the underwater section.
- The Thrust Force
The bow thruster is required to apply a countering thrust force, which is
at least equal to the thrust force applied by the wind. The required
thrust force of the bow thruster may now be calculated by dividing the
torque by the distance between the center of the bow thruster and the
pivot point of the boat.
Wind Speed - Wind Pressure Chart
Wind Speed
knots |
Description |
Wind Speed
ft/s |
Wind pressure lbf/sq.ft. |
10 -
16
16 - 22
22 - 28
28 - 34
34 - 40 |
moderate breeze
fresh breeze
strong breeze
near breeze
gale |
17 -
27
27 - 37
37 - 47
47 - 57
57 - 67 |
0.40 -
1
1 - 1.9
1.9 - 3.1
3.1 - 4.6
4.6 - 6.3 |
Calculation example
The boat has an
overall length of 36 ft and the lateral wind draft measures 190 sq.ft.
It is required that the bow can still be controlled easily when a wind
force of 20 knots applies. At a wind force of 20 knots, the wind
pressure is:
p = 1.0 to 1.9 lbf/sq.ft i.e.p. (average) 1.45 lbf/sq.ft.
The required torque reads:
T = windpressure x wind draft x reduction factor x
distance center of effort to pivot point, (=appr. half the ship's
length)
T = 1.45 lbf/sq.ft x 190 sq/ft x 0,75 x 36 ft/2 =
3719 ft.lbs.
The required Thrust Force is calculated as
follows:
F = Torque/distance between the center of bow
thruster and the pivot of the boat
= 3719 ft/lb / 34.5 ft = 107.8 lb
The VETUS bow thruster which is most suitable for
this particular vessel is the 121 lbf model.
Always bear in mind that the effective
performance of a bow thruster will vary with each particular boat, as
the displacement, the shape of the underwater section and the
positioning of the bow thruster will always be variable factor. |
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