Page 211 - Vetus

STABILIZERS (HYDRAULIC)

Do they affect the speed?
In smooth water with the stabilizers not in use, the speed reduction is negligible (for example: about 1 knot at 25 knots for a
82 feet (25 metre) vessel). In heavy seas however, a vessel using stabilizers has the advantage, because the boat rolls less and
therefore has a lower wetted surface area.

Which size?
B = The waterline beam in metres.
D = The displacement in metric tons. The fin size can be calculated using the
T = The roll period in seconds. This following formula:
2
is the time taken to roll from Fin surface in m = 3,5 x B x D
2
starboard to port and back to STAFIN T x V 2
starboard again. The amplitude The recommended fin size is as follows:
is not important here since
the roll period always remains 3,5 x 3,6 x 23 = 0,33 m 2
3,5 x 8,5
2
2
constant. The roll period can
therefore be measured fairly Thus, a fin size of 0.4 m should be chosen
2
easily by causing the vessel 2
to roll gently when moored or 0.3 m if space is restricted.
alongside the quay.
V = The cruising speed in knots.
03 04 05 06 07
A 5 19 /32” 6 59 /64” 8 15 /32” 9 27 /32” 11 29 /64”
Example B 16 31 /32” 9 9 /16” 21 13 /16” 23 5 /8” 23 13 /16”
A 44.2 ft (13.5 m) motor yacht has waterline beam of 11.8 C 24 13 /32” 28 3 /16” 31 17 /32” 34 3 /8” 40 13 /64”
ft (3.6 metre). The displacement is 23 metric tons and the D 31 27 /64” 36 17 /64” 40 5 /16” 44 19 /64” 51 57 /64”
cruising speed is 8.5 knots. Roll period is 3.5 sec. E 1 /64” 1 /64” 1 /64” 1 /32” 1 /32”

The position of the Scope of supply
fins STA24VA consisting of four
hydraulic cylinders with associated
The stabilizers are most
effective if they are located 40 valve block, a control panel and
a solid-state gyroscope (which
to 50% of LWL from the bow.
The fin tips must be located registers the vessels movement).
The standard power supply is
within the beam of the vessel
as far as is possible, so as to 24 Volt DC (a 12 Volt to 24 Volt
transformer is available as an
avoid damage when mooring
alongside. Guide bushes option).
must be laminated or welded A pair of fins. The stock and
through the hull sections for blade are made from stainless
the fin stocks to pass through. steel and the blade is filled with
polyurethane. There is a choice of
5 fin sizes available: 0.3, 0.4, 0.5,
0.6 and 0.7m . STA24VA
2
A pair of guide bushes, available
for steel, GRP or aluminum hulls.
The high pressure hoses are not
included and should be ordered
separately to the required lengths.
VETUS stabilisers overview
• “Plug and Play” installation for steel, GRP and aluminum vessels
• Fully automatic operation
• The fin movement is automatically adjusted according to the degree of
damping selected, the speed of the vessel and the sea state
• All electronic components are solid state

From the control panel the stabilizers can be switched on or
off or centered for when going astern. The required amount of
damping can be adjusted and the roll amplitude is displayed.
Specifications
• Dimensions: 8 /4” x 3 /32” x 4”
11
1
(210 x 85 x 103 mm)
• Meets the EMC requirements
Creators of Boat Systems 211