Stabilizing system for a boat

At least two trim tabs 12 are mounted on the transom 11 symmetrically on each side of the longitudinal axis of the hull 10. Each trim tab 12 includes a plate 15 mounted on at least two rocker arms 16 for pivotal movement relative to the transom 11 and two or more hydraulic actuators 20 and 21 for pivoting the plate 15 relative to the distal ends of the rocker arms 16.

FIELD OF THE INVENTION 
This invention relates to stabilizing systems for boats. In particular, it 
relates to a system comprising two or more trim tabs mounted on the 
transom of a boat. 
SUMMARY OF THE INVENTION 
A stabilizing system according to the invention comprises at least two trim 
tabs mounted on the transom of the boat symmetrically on either side of 
the longitudinal axis of the boat. Each trim tab comprises a plate mounted 
on at least two rocker arms for pivotal movement relative to the transom 
and means for pivoting the plate relative to the distal ends of the rocker 
arms. 
GENERAL DISCUSSION OF THE INVENTION 
The stabilizing system according to the invention is a mechanical device 
designed for the marine industry to combine in one device the functions of 
trim tabs and the functions of stabilizers. The stabilizing system enables 
two jobs to be done by one device instead of two jobs to be done by two 
separate devices. Moreover, with the stabilizing system according to the 
invention, the operator has a control over the ride that is normally 
better than the control over the ride provided by a combination of the 
other systems now commercially available. 
The stabilizing system according to the invention is designed not only to 
create lift on the stern of almost any sized boat, thereby giving 
forward-to-aft (front-to-rear) level ride, but also to stabilize the boat 
port-to-starboard (left-to-right). 
The stabilizing system according to the invention trims and stabilizes by 
the use of two or more double-hinged planing surfaces that are mounted on 
the transom, at least one on the port side of the keel and at least one on 
the starboard side of the keel. Each of the planing surfaces is equipped 
with two independently operated hydraulic actuators. One such hydraulic 
actuator functions as the port-to-starboard stabilizing actuator, while 
the other such hydraulic actuator functions as the forward-to-aft trimming 
actuator. 
On a condition of port roll, the starboard side port-to-starboard hydraulic 
actuator extends, thereby causing the starboard planing surface to extend 
below the planing surface of the hull, toe first, creating a negative lift 
that causes the starboard side of the boat to roll to starboard. At the 
same time, the port side port-to-starboard hydraulic actuator retracts, 
thereby creating heel-down of the associated planing surface, creating 
positive lift and thereby causing the port side of the boat to be raised. 
Once the boat attains a horizontal attitude from port-to-starboard, the 
port-to-starboard hydraulic actuators reverse their actions, thereby 
bringing the planing surfaces to a neutral state. This action is 
controlled hydraulically by a "brain box" that has the ability to create 
an artificial horizon as a means of controlling the port-to-starboard 
hydraulic actuators for stabilization. 
The forward-to-aft trimming hydraulic actuators control the heel of the 
planing surfaces, thereby controlling the forward-to-aft attitude of the 
boat. 
It should be particularly noted that the degree of trimming forward-to-aft 
is independent of the amount of stabilization port-to-starboard. The 
trimming aspect is controlled by a switch that is preferably conveniently 
located in a piloting area (i.e., at the helm). The stabilizing aspect of 
the planing surfaces is adjusted in such a way from the helm as to give 
light stabilization for light sea conditions and heavy stabilization for 
heavy sea conditions. 
So far this is known by the inventor, the concept of the stabilizing system 
according to the invention is non-existent at this time in the form of one 
individual mechanism functioning as both a port-to-starboard stabilizer 
and a forward-to-aft trimmer. That is, at this point in time, trim tabs do 
one function and stabilizers do the other function. The stabilizing system 
according to the invention combines the two aforementioned functions into 
one. The result is a much smoother ride and a ride that is much more 
controllable by the operator, as well as being much more efficient. 
The stabilizing system according to the invention is preferably 
hydraulically actuated and is powerful enough to be used at the highest 
speeds contemplated for use by the boat. By combining a forward-to-aft 
level ride (trim tabs) with a port-to-starboard level ride (stabilizers), 
the stabilizing system according to the invention actually balances the 
overall level of the boat for a very smooth ride. Due to the location of 
the stabilizing system according to the invention, its functioning is 
intensified because the planing surfaces are fed by thrusts from the 
propellers, as opposed to eddied water from the hullsides, as is the case 
with currently manufactured stabilizers. 
Another disadvantage of current stabilizers is that they cause drag which 
reduces the speed and efficiency of the vessel, as well as making the 
vessel extremely vulnerable to collision and/or grounding. Certain types 
of presently manufactured stabilizers do have the ability of being 
retracted when not in use, but at the cost of considerably more machinery 
and maintenance. The stabilizing system according to the invention, 
however, is not in danger of either collision or grounding whether or not 
the planing surfaces are in use, since the planing surfaces are fully 
protected by the keel and by the propellers. 
Finally, drag is minimized due to the fact that the planing surfaces are 
only momentarily submerged to obtain appropriate action, as opposed to 
being continually submerged -- as are conventional fins.

DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENT 
Turning first to FIGS. 6 and 7, a hull 10 having a transom 11 will be seen. 
Two trim tabs 12 are symmetrically mounted on the transom 11 for use in 
counteracting rolls and in adjusting the yaw angle of the boat. 
Preferably each trim tab 12 comprises a plate 13 that is adapted to be 
mounted on the transom 11 by means of bolt holes 14 (shown in FIG. 1) or 
the like. Preferably the plate 13 is rectangular in shape and has a top 
and a bottom. Alternatively, the remainder of each trim tab 12 can be 
mounted directly on the transom 11--that is, the plate 13 can be dispensed 
with. 
A plate 15 is pivotally mounted on the plate 13 or the transom 11 by means 
of two rocker arms 16. Preferably the plate 15 is rectangular in shape and 
has a proximal side and a distal side. Each of the rocker arms 16 has a 
proximal end pivotally attached to the plate 13 or to the transom 11 and a 
distal end pivotally attached to the plate 15 at a first axis 17 
intermediate its proximal and distal sides. 
At least one mounting bracket projects from the plate 13 or the transom 11. 
Preferably first and second mounting brackets 18 and 19 project in 
parallel from the plate 13 or from the transom 11. First and second 
hydraulic actuators 20 and 21 are pivotally attached to the first and 
second mounting brackets 18 and 19 and to the plate 15. The first 
hydraulic actuator 20 has a first end pivotally mounted between the first 
and second mounting brackets 18 and 19 at a second axis 22 spaced from the 
plate 13 or from the transom 11 and a second end pivotally attached to the 
plate 15 at a third axis 23 spaced from its proximal side. The third axis 
23 is preferably (but not necessarily) located inwardly from the first 
axis 17. The second hydraulic actuator 21 has a first end pivotally 
mounted between the first and second mounting brackets 18 and 19 at a 
fourth axis 24 spaced outwardly from the second axis 22 and a second end 
pivotally attached to the plate 15 at a fifth axis 25 spaced outwardly 
from the third axis 23. 
Preferably the distance between the fourth axis 24 and the fifth axis 25 is 
greater than the distance between the second axis 22 and the third axis 
23. 
Also preferably each one of the first and second hydraulic actuators 20 and 
21 comprises a cylinder (or dead-end) 26 pivotally attached to the first 
and second mounting brackets 18 and 19 and a piston rod (or live-end) 27 
pivotally attached to the plate 15. 
The position of the plate 15 is controlled by actuation of the first and 
second hydraulic actuators 20 and 21 as illustrated in the drawings under 
the control of an onboard computer. Since the control of trim tabs by such 
onboard computers is well known in the art and forms no part of this 
invention, it will not be described further herein. 
Obviously, numerous modifications and variations of the present invention 
are possible in light of the above teachings. It is therefore to be 
understood that, within the scope of the appended claims, the invention 
may be practiced otherwise than as specifically described herein.