Powerboat rooster tail depressor
A powerboat with a rooster tail depressor (RTD) includes a hull, a propulsion subassembly on the hull, and a rooster-tail-suppressing canopy on the stern that includes a downwardly facing surface no less than six inches above the dynamic water line of the stern where it functions to suppress the powerboat rooster tail for radar signature reduction and increased propulsion efficiency. Various embodiments include one or more of (i) a canopy having a downwardly facing surface that is arched (either curved or faceted), (ii) lift-to-drag ratio enhancing steps in the downwardly facing surface of the canopy, (iii) a rooster-tail-suppressing subassembly configured to enable articulation of the canopy in yaw and in trim, and (iv) operator-controlled port and starboard venting arrangements on the canopy that result in desired laterally directed thrust for enhanced maneuverability.
1. A powerboat, comprising:
a hull having a stern, said stern having a dynamic water line;
a propulsion subassembly on the hull that functions as means for propelling the hull through water with sufficient power to produce a powerboat rooster tail; and
means for suppressing the powerboat rooster tail, including a rooster-tail-suppressing subassembly on the boat hull that extends rearwardly of the stern;
wherein the rooster-tail-suppressing subassembly includes a canopy having a downwardly facing surface extending rearwardly of the stern, said downwardly facing surface having an upper region that is disposed at least six inches above a horizontal reference plane containing the dynamic water line;
wherein the canopy has a port side and a starboard side such that the port side and the starboard side extend downwardly from the downwardly facing surface so that the port side and starboard sides obstruct lateral movement of the powerboat rooster tail;
wherein the port side includes first means for venting the powerboat rooster tail to port to produce a net starboard-directed lateral thrust that facilitates turning the hull to port; and
wherein the starboard side includes second means for venting the powerboat rooster tail to starboard to produce a net port-directed lateral thrust that facilitates turning the hull to starboard.
2. A powerboat as recited in claim 1 , wherein:
the port side defines a first opening for enabling passage of the powerboat rooster tail to port;
the starboard side defines a second opening for enabling passage of the powerboat rooster tail to starboard;
the first means for venting the powerboat rooster tail to port includes a first panel configured to be moved under operator control between a NON-VENTED position of the first panel in which the first panel obstructs passage of a portion of the powerboat rooster tail through the first opening and a VENTED position of the first panel in which the first panel facilitates passage of a portion of the powerboat rooster tail through the first opening; and
the second means for venting the powerboat rooster tail to starboard includes a second panel configured to be moved under operator control between a NON-VENTED position of the second panel in which the second panel obstructs passage of a portion of the powerboat rooster tail through the second opening and a VENTED position of the second panel in which the second panel facilitates passage of a portion of the powerboat rooster tail through the second opening.
3. A powerboat as recited in claim 2 , wherein the first and second panels are moveable vertically between the NON-VENTED and VENTED positions.
4. A powerboat as recited in claim 2 , wherein the first and second panels are pivotable between the NON-VENTED and VENTED positions.
5. A powerboat as recited in claim 1 , wherein:
the first means for venting the powerboat rooster tail to port includes a first shutters-type of venting arrangement as part of the port side of the canopy such that the first shutters-type venting arrangement is configured to be moved under operator control between a NON-VENTED position of the first shutters-type venting arrangement in which the first shutters-type venting arrangement obstructs passage of a portion of the powerboat rooster tail to port and an VENTED position of the first shutters-type venting arrangement in which the first shutters-type venting arrangement facilitates passage of a portion of the powerboat rooster tail to port; and
the second means for venting the powerboat rooster tail to starboard includes a second shutters-type venting arrangement as part of the starboard side of the canopy such that the second shutters-type venting arrangement is configured to be moved under operator control between a NON-VENTED position of the second shutters-type venting arrangement in which the second shutters-type venting arrangement obstructs passage of a portion of the powerboat rooster tail to starboard and an VENTED position of the second shutters-type venting arrangement in which the second shutters-type venting arrangement facilitates passage of a portion of the power rooster tail to starboard.