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6463
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2022
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SPS-B
MC_0207
Fin Positioning
Transversal fi n positioning of Vector Fins
TM
With Vector fi nsTM it is a priority to push the fi ns as far outboard as possible to achieve the most leverage for the fi ns forces unlike standard fi ns.
With Sleipner stabilizers enable installation of the fi ns to have different stroke angles inboard and outboard as the locked centre and cruising centre is
flexible because they are locked hydraulically.
Avoid cutting off any of the back top section of the fi n (normal on most fi ns on hard-chine boats) as this will cause added resistance/ drag by the fi n.
(NB: Common on fi ns on hard-chine boats)
. This will create a recess area that will allow water at higher speeds and anchor stabilization to lose force
also as part of the water will pass easier between the hull and the fi n. Additional due to the outward ”bend” of the fi ns keeping the lower part inside
the boats ”envelope” it will result in the upper part of the fi ns being further inboard that creates less of an outboard stroke in the upper part of the fi n
(along the hull).
Finding the best position for the fi n and actuator positioning often is related to the inside confi guration and space that is required for proper
installation.
General Rules:
–Push the actuators as far as possible outboard, keeping at least 22 degrees of outboard stroke as a minimum
(NB: if less, and the lower part is within
boat envelope, a small cut-away of the back upper part can be done as a compromise).
It is also acceptable installing the fi ns further inboard If inside confi guration/ access to inside parts of actuators is required.
(NB: Performance will be
reduced slightly due to less leverage arm for the stabilizing force applied by the fi ns.)
MG_0214
VF650
575 / 810
350 / 625
VF800
642 / 900
390 / 695
VF1050
731 / 1016
444 / 791
VF1350
828 / 1150
504 / 897
VF1650
914 / 1305
557 / 1001
*VF1950
*991 / *1386
674 / 1112
Measurements along hull bottom outwards to chine(upper) and outside boat ”envelope” (lower) in mm,
center shaft to chine start / outside envelope:
At maximum: 38
o
o
At minimum : 22
Fin size
Upper / lower
Upper / Lower
“Top” view
“Boat” view
38°
Lower
at min:
22
Lower
at max:
38
Upper
at min:
22
Upper
at max:
38
Upper limit for Fin
Lower limit for Fin
W.L
o
o
o
o
To avoid unwanted influences on the steering characteristics, the fi ns should be placed close to the vessel longitudinal centre of gravity (LCG)
- If unknown, this is usually a little aft of 50% of the waterline length.
For high speed vessels, the fi ns should be placed with trailing/leading edge within middle 1/4 of waterline length at speed and not in front of the
LCG.
For vessels with top speed under 15 knots, fi n may be placed within the middle 1/4 of waterline length.
Waterline at rest
Waterline at speed
Middle 1/4 of
Waterline at speed
Middle 1/4
of Waterline
MC_0207
Fin Positioning
IMPORTANT
These are general guidelines and some hull types might allow for an installation position outside of this recommendation.