Arrangement for dynamic control of running trim and list of a boat

The invention pertains to an arrangement for dynamic control of running trim and list of a boat, having at least one hull with a stern. The arrangement (100) has a housing member (102), an interceptor member (103, 103'), an actuator (105) and a power supply (106). The actuator (105) is arranged for displacing the interceptor member (103, 103') in a continuous linear movement between first (103) and second end positions (103') or vice versa in relation to said housing member (102), which comprises an attachment (104, 104', 104", 104'") for attachment to the hull. The interceptor member (103, 103') has a first portion (107) and a second (108) portion, wherein the first portion (107) extends essentially perpendicularly from the middle of the entire length of the second portion (108). The housing member (102) partially encloses the first portion (107) so that the housing member (102) firmly guides the first portion (107) during the linear movement. The housing member (105) further defines an internal space, inside of which the actuator (105) is accommodated (102). The present invention is applicable for dynamic control of running trim and list of boats, in particular for planing or semi-planing boats. However, the invention is also applicable for larger vessels.

TECHNICAL FIELD 
The present invention pertains to an arrangement for dynamic control of 
running trim and list of a boat having at least one hull with a stern. The 
arrangement has a housing member and an interceptor member, which is 
linearly displaceable in relation to the housing member, wherein the 
housing member has attachment means for attaching the arrangement to the 
hull of the boat. The present invention is applicable for dynamic control 
of running trim and list of boats, in particular for planing or 
semi-planing boats. However, the invention is also applicable for larger 
vessels. 
BACKGROUND OF THE INVENTION 
A number of different devices and arrangements intended for dynamic control 
of running trim of boats are previously known. 
One such previously known arrangement comprises the use of a so-called 
interceptor member, constituted of a plate or interceptor member arranged 
transverse to the vessel bottom and attached thereto. Such an interceptor 
member increases the water pressure acting on the bottom of the hull in 
front of the interceptor member and, accordingly, changes the running trim 
of the boat or vessel. 
Furthermore, the patent publication SE-C2-502 671 discloses a device for 
dynamic trimming of a planing or semi-planing vessel hull. The disclosed 
device comprises a trim plate, directly behind the hull bottom in the path 
direction, which has been inserted into the relative water flow and 
crossways to it. The trim plate produces at least one main vortex with an 
upwardly and forwardly directed force component in front of the trim 
plate. According to SE-C2-502671, this causes the formation of a water 
volume with an increased pressure acting against a zone of the hull bottom 
in front of the trim plate. The trim plate is preferably inserted to a 
continuously adjustable depth, corresponding to 0-3% of the trim plate 
length and preferably at the most corresponding to 2.7% of its length. 
Furthermore, the trim plate preferably extends along an essential portion 
of the hull width and preferably along the whole width of the hull bottom 
or bottom halves. 
According to SE-C2-502 671, the disclosed device provides a number of 
advantages such as rapid response, low power consumption, high utilization 
of the supplied trimming energy, low mechanical stress on the movable 
parts, and no disturbance of a reversing water jet. 
Something which might be perceived as a problem with the previously known 
arrangements for dynamic control of running trim of a boat is that they 
usually are supplied in the form of a number of separate parts and/or 
units. 
Accordingly, previously kcnown arrangements might comprise an interceptor 
member provided with elongated apertures which are slidably mounted on the 
boat hull, e.g. by means of guide pins which are fixedly attached to the 
hull. Such a previously known arrangement also comprises a separate 
actuating means, for displacing the interceptor member to the desired 
position in relation to the hull. In such a case, also the actuating means 
has to be fixedly attached to the hull of the boat by means of separate 
attachment means, something which of course might result in undesired 
damage to the hull surface and/or the hull structure. 
Furthermore, in order to achieve sufficient stability and power for linear 
displacement of the interceptor member, the previously known arrangements 
normally require the use of several actuating means acting on the 
interceptor member. 
SUMMARY OF THE INVENTION 
Accordingly, the object of the present invention is to provide an 
arrangement for dynamic control of running trim and list of a boat, which 
arrangement overcomes the above-mentioned problems with the previously 
known arrangements, and provides a compact, stable and reliable unit, 
which easily can be installed on the hull or hulls of a boat with a 
minimum of damage to the hull or hulls. 
This object is achieved, in accordance with claim 1, by means of an 
arrangement having a housing member and an interceptor member, wherein the 
arrangement further has an actuating means and a power supply means. The 
actuating means is arranged for displacing the interceptor member in a 
continuous linear movement between first and second end positions or vice 
versa in relation to the housing member. According to the invention, the 
housing member comprises attachment means for attaching the arrangement to 
the hull. The interceptor member has a first portion and a second portion, 
wherein the first portion extends essentially perpendicularly from the 
middle of the entire length of the second portion. Thereby, the housing 
member partially encloses the first portion so that the housing member 
firmly guides the first portion during the linear movement. 
The housing member further defines an internal space inside of which the 
actuating means is accommodated.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT 
In the following, an arrangement according to the invention will be 
described with reference to FIGS. 1-9. Furthermore, a preferred embodiment 
and several advantageous and alternative embodiments will be disclosed. 
The arrangement 100 according to the invention is intended for dynamic 
control of running trim and list of a boat, wherein the boat has at least 
one hull with a stern 101. Accordingly, the arrangement according to the 
invention can be utilized both for single hull boats and for boats or 
vessels with several hulls. 
The arrangement 100 according to the invention has a housing member 102 and 
an interceptor member 103, 103'. 
In the preferred embodiment, both the housing member 102 and the 
interceptor member 103, 103' are made of fibrere-inforced polyacetal 
resin. In this embodiment, the interceptor member 103, 103' is constituted 
of a single component of fibre-reinforced polyacetal resin, whereas the 
housing member 102 is constituted of a generally T-shaped component and a 
cover which has been firmly attached to one of the legs of the generally 
T-shaped component. 
However, embodiments wherein the housing member 102 and/or the interceptor 
member 103, 103' are made of other non-reinforced or reinforced plastic or 
composite materials, or embodiments wherein the housing member 102 and/or 
the interceptor member 103, 103' are made of metal, e.g. stainless steel, 
aluminium, rubber or another suitable material are also conceivable. 
Furthermore, embodiments of the invention are also conceivable in which 
the housing member and/or the interceptor member is/are constituted of 
more components than what is shown in the attached drawings, wherein 
several components have been assembled together into the desired shapes. 
The arrangement 100 according to the invention further includes an 
actuating means 105 and a power supply means 106. The actuating means 105 
is arranged for displacing the interceptor member 103, 103' in a 
continuous linear movement between first 103 and second 103' end positions 
or vice versa in relation to the housing member 102. 
According to the invention, the housing member 102 comprises attachment 
means 104, 104', 104", 104'" for attaching the arrangement 100 to the hull 
of the boat. Furthermore, the interceptor member 103, 103' has a first 
portion 107 and a second portion 107, 108. The first portion 107 extends 
essentially perpendicularly from the middle of the entire length of the 
second portion 108, i.e. the interceptor member 103, 103' has a T-shape. 
The housing member 102 partially encloses the first portion 107, so that 
the housing member 102 firmly guides the first portion 107 during the 
linear movement of the interceptor member. As is most clearly evident from 
FIGS. 2, 6 and 7, external surfaces of the first portion 107 are guided by 
partially enclosing portions of the housing member 102. Thereby, the 
T-shape of the interceptor member 103, 103' makes it possible to obtain a 
stable guiding effect on the first portion 107, during the linear movement 
of the interceptor member 103, 103'. Embodiments of the invention, wherein 
the housing member 102 encloses more or less of the first portion 107 than 
what is shown in the attached drawings, are also conceivable. 
Furthermore, according to the invention, the housing member 102 defines an 
internal space, inside of which the actuating means 105 is accommodated. 
Thereby, many different designs of the housing member 102 are conceivable. 
In the preferred embodiment, both the interceptor members 103, 103' and the 
housing member 102 have a T-shape. However, it is also conceivable to have 
embodiments wherein only the interceptor member has a defined T-shape, or 
wherein the interceptor member has a T-shape which is different from the 
T-shape of the housing member. 
In the preferred embodiment, as shown in FIGS. 1 and 2, the attachment 
means 104, 104'" are constituted of a number of pre-drilled through-holes 
in the horizontal portion of the T-shaped housing member 102, and of 
protruding tabs 104', 104", also having pre-drilled holes, attached to 
upper corners of the vertical portion of the, in the preferred embodiment, 
T-shaped housing member 102. 
Using the pre-drilled holes, the housing member 102 can be fixedly attached 
to the stern 101 of the boat by means of, for example screws. The 
attachment means 104, 104', 104", 104'", with their pre-drilled holes, are 
arranged in a predetermined pattern which is designed in order to provide 
sufficient attachment stability when the arrangement is mounted onto the 
hull. However, embodiments of the invention with other types and 
configurations of attachment means than those shown in the attached 
drawings are also conceivable. 
According to the preferred embodiment of the invention, the arrangement 
further includes sealing means 112, 112', 112", 112'". In the preferred 
embodiment, as is best shown in FIG. 5, a number of the sealing means 112, 
122' are in sealing contact with different parts which constitute the 
housing member 102, while other sealing means 112", 112'" are in sealing 
contact with both the housing member 102 and the actuating means 105, in 
order to se al the in ternal space defined by the housing member 102 
against water. In the preferred embodiment, the sealing means 112, 112', 
112', 112" are constituted of so-called O-rings of rubber, but many other 
types of sealings and sealing configurations are conceivable. 
The T-shape of the interceptor member 103, 103', and in the preferred 
embodiment also of the housing member 102, provides several important 
advantages. Firstly, a T-shaped housing member 102 makes it possible to 
obtain high is attachment stability with a low material consumption. 
Secondly, a T-shaped interceptor member 103, 103' together with a T-shaped 
housing member 102 form a compact, waterresistant unit 100 with low 
weight. Thus, the arrangement according to the invention can easily be 
mounted on the hull of a boat, after which the power su pply means 106 is 
connected to a suitable power source, and the arrangement 100 is ready for 
use. 
In an advantageous embodiment of the arrangement according to the 
invention, the first portion 107 of th e interceptor member 103, 103' is 
intended to be substantially vertical and the second portion 108 is 
intended to be substantially horizontal to the plane of a water surface 
when the arrangement 100 is attached to the hull. When the boat is running 
across a surface of the water volume 109 and the arrangement 100 is 
attached to the hull, as is evident from FIG. 4, the second portion 108 is 
designed for providing the water volume 109 with an increased pressure 110 
acting on a region 111 of the hull in front of the stern 101 when the 
interceptor member 103, 103' is in the second end position 103' or in a 
position between the first 103 and second 103' end positions. As is most 
clearly evident from FIGS. 3 and 4, the housing member 102 is thereby 
designed for absorbing the forces created by the increased pressure 110 
and acting on the second portion 108. In this embodiment, the housing 
member 102 is further designed for distributing and transferring the 
absorbed forces to the hull when the arrangement 100 is attached to the 
hull. 
In this embodiment, the desired effect of force absorption, transfer and 
distribution is achieved, for example, by giving the cross-section of the 
housing member 102 an E-shape, wherein the lower leg of the E-shape 
absorbs a large portion of the forces acting on the second portion 108 of 
the interceptor member 103' when it is in an activated position, i.e. not 
in its first position 103. The middle and the upper leg of the E-shape 
distribute and transfer the absorbed forces to the hull of the boat. 
However, embodiments with other designs providing the same effect are also 
conceivable. 
In another advantageous embodiment, and with particular reference to FIG. 
5, the actuating means 105 comprises an electrical motor 113, a gear unit 
114 and a transmission member 115. The electrical motor 113 is arranged 
for providing a rotational movement which via the gear unit 114 is 
transferred to the transmission member 115, which is arranged for 
transforming the rotational movement into a linear movement which is 
transferred to the interceptor member 103, 103'. However, many other 
embodiments of the transmission member 115 are conceivable. In the 
described embodiment, the transmission member 115 is constituted of a 
screw with external threads, engaging with internal threads of a 
substantially cylindrical recess inside a cover member of the transmission 
member 115. In the described embodiment, the s crew is carried in bearings 
of the housing member 102, while the cover member is attached to the 
second portion 108 of the interceptor member 103, 103', something which is 
evident from FIG. 7. In this embodiment, the power supply means 106 is 
constituted of an electrical power supply of a conventional type for 
marine applications. 
As is evident from FIG. 8, it is also conceivable to have embodiments of 
the invention, wherein the actuating means 205 comprises a hydraulic 
device with a spring means 219 and a transmission member 215, i.e. a 
piston. In such an embodiment, the hydraulic device is arranged for 
providing a movement which is transferred to the transmission member 215, 
wherein the transmission member 215 is arranged for transferring the 
movement to the interceptor member 203 in order to linearly displace the 
interceptor member 203 towards the second end position. Furthermore, the 
spring means 219 are arranged for linearly displacing the interceptor 
member 203 towards the first end position, i.e. in the opposite direction. 
In such an embodiment, the power supply means 206 is a hydraulic power 
supply. 
Embodiments of the invention are also conceivable in which the actuating 
means comprises a hydraulic device, but no spring means (not shown in the 
drawings). In such an embodiment, the hydraulic device is arranged for 
linearly displacing the interceptor member both to and in a direction from 
the second end position. 
Furthermore, embodiments of the invention are also conceivable, wherein the 
actuating means comprises a crank means, a gear unit and a transmission 
member (not shown in the drawings). Thereby, the crank means is arranged 
for providing a movement which, via the gear unit, is transferred to the 
transmission member, which is arranged for transferring the movement to 
the interceptor member. In such an embodiment, the power supply means is a 
manual power supply, i.e. the crank means are operated by hand by the boat 
crew. Such an embodiment of the arrangement according to the invention is 
particularly suitable for smaller boats. 
In advantageous embodiments of the invention, as is evident from FIGS. 5, 7 
and 8, the arrangement 100; 200 further comprises a position transducer 
116; 216, which is arranged inside the internal space defined by the 
housing member 102; 202, for detecting the position of the interceptor 
member 103; 203 and for transmitting a signal to an indicating unit (not 
shown) on board the boat via a transmission line 120; 220. Thereby, the 
transmitted signal corresponds to the position of the interceptor member 
103; 203. In the embodiments shown in the drawings, the position 
transducer 116; 216 is of an inductive type and includes an annular magnet 
117; 217 in a manner known per se. However, embodiments with other designs 
of the position transducer 116; 216 are also conceivable, e.g. transducers 
of a resistive type. 
In one advantageous embodiment of the invention, the arrangement 100 is 
attached to a substantially vertical surface of the stern 101 of the boat, 
wherein the entire length of the second portion 108 of the interceptor 
member extends along a limited portion of the horizontal width of the 
surface of the stern 101. 
In another advantageous embodiment of the invention, the arrangement is 
attached to a substantially vertical surface of the hull in front of the 
stern, wherein the entire length of the second portion of the interceptor 
member extends along a limited portion of the horizontal width of the 
surface of the hull in front of the stern. Such an embodiment can 
advantageously be used when, for some reason, attachment of the 
arrangement to the stern of the boat is impossible or difficult, e.g. when 
the stern is sloping or comprises surfaces at an angle to the longitudinal 
axis of the boat. 
However, embodiments of the invention are also conceivable wherein the 
arrangement is attached to a surface of the boat hull which forms an angle 
to the water surface upon which the boat floats. 
Embodiments of the present invention are also conceivable, wherein the 
arrangement comprises more than one housing member, interceptor member, 
actuating means, and power supply means, which all are attached to the 
hull of the boat. Such embodiments provide more possibilities, where the 
dynamic control of the running trim and list of a boat is concerned, and 
may also be utilized for changing the travelling direction of a running 
boat or vessel. 
Furthermore, there are advantageous embodiments of the invention, wherein 
the boat is provided with more than one hull, e.g. catamarans. In such 
embodiments, one or several complete arrangements according to the 
invention are attached to one or several of the hulls of the boat, i.e. 
the number of housing members, interceptor members and actuating members 
is identical and, accordingly, corresponds to the number of arrangements 
according to the invention which is utilized. 
In FIG. 9, an alternative embodiment of the arrangement 300 according to 
the invention is shown. In this embodiment, the housing member 302, 302' 
comprises a generally cylindrical first member 302, which accommodates the 
actuating means (not visible in the drawing), and a T-shaped second member 
302', which is attached 321 to the first member 302 and provides the 
desired guiding effect on the first portion (not visible in the drawing) 
of the interceptor member 303. Furthermore, the T-shaped second member 
302' of the housing member 302, 302' provides attachment means 304, 304', 
304", 304'" for attachment of the arrangement 300 to the hull of a boat. 
In this embodiment, a transmission member 315, which is actuated by the 
actuating means, protrudes from the first member 302 and is attached to 
the interceptor member 303. 
The present invention is not limited to the embodiments described above and 
shown in the attached drawings, but can of course be varied within the 
scope of the following claims. 
For example, when the invention is utilized primarily for dynamic control 
of running trim of a boat, one single arrangement according to the 
invention or several cooperating arrangements according to the invention 
can be used. In this case the arrangement or the cooperating arrangements 
is/are activated to the degree necessary in order achieve the desired 
running trim of the boat, e.g. in order to avoid that the bow of the 
running boat rises too high. 
When the invention instead is utilized primarily for dynamic control of 
list of a boat, a pair of arrangements according to the invention are 
suitably used. Thereby, one of the arrangements according to the invention 
is attached close to the starboard end of the stern, while the other 
arrangement is attached closer to the port end of the stern. In this case, 
the pair of arrangements according to the invention are activated in an 
individual manner, i.e. the arrangement at the end of the stern of the 
running boat which is closer to the water surface is activated to a higher 
degree than the arrangement attached to the opposite end of the stern. 
However, embodiments of the invention are also conceivable wherein more 
than two arrangements according to the invention are utilized for the 
above-described control strategy. 
If the two above-described strategies are combined, dynamic control of both 
running trim and list of a running boat can be achieved by means of the 
invention. 
Furthermore, the arrangement or arrangements according to the invention can 
be connected to a suitable control system of any previously known type, 
e.g. a computerized control system on board a boat or vessel.