Abstract: A deflecting propeller guard comprising a pair of adjacent deflector plates slanting downwardly and rearwardly from a front apex location to provide downwardly and laterally facing deflection surfaces. There is a rear guard section having two guard plates positioned adjacent to one another and extending outwardly and upwardly at a moderate slant from a center axis. The deflecting propeller guard is positioned with the guard section below the propeller and the deflecting section forwardly of the propeller. A center mounting plate is provided to be positioned adjacent to, and connected to the skeg of the motor assembly.

Abstract: A hydrofoil propeller guard, including a thrust tube, a hydrofoil fin and bottom securing plate, is used in conjunction with an outboard motor mounted on a boat and with stern drives, to encompass the propeller to reduce sideways thrust, to move items away from the propeller, and the guard preferably includes a trolling plate to increase slow speed performance.

Abstract: A propeller guard including a multi-angled band formed of a plurality of independently radiused sections. The band may also include a plurality of evenly spaced ports therethrough. The multi-angled band is designed to improve the performance characteristics, specifically acceleration, planing, speed and steering, of the motor. The band is attached to the motor by an attachment bracket which is designed to inhibit fatigue and cyclical loading failure caused by vibrations of the band during use. The band may also include convex tapered inlet and outlet openings.

Abstract: An outboard or stern marine drive assembly includes a skeg that is detachably secured to the lower gear case. The skeg plane is laterally off-set from the vertical plane that passes through the propeller thrust axis. One embodiment of the thin, high-strength steel skeg is secured by a "T" section along the top edge of the skeg to mesh longitudinally with a corresponding T slot in the gear case wall. In another embodiment, the skeg is flush mounted to a boss surface cast integrally with the shell wall of the gear case.

Abstract: A lift-generating device for a power boat includes a boundary (4) of semi-circular form in cross section mounted beneath the propeller (5) of the boat so that the propeller (5) produces a high-speed water flow over the upwardly facing surface of the boundary (4), thereby creating lift.

Abstract: A sound deflector comprising of a curved deflecting surface, with the deflector being connected to the back of a boat. The sound deflector deflects the sounds emitting from the outboard of a boat away from the passengers in the cockpit. The deflector is composed of sound deflecting material and encompasses the engine over the waterline.

Abstract: A weed guard system for trolling motors comprises a bracket structure attached to the boat and capable of allowing the motor to articulate arcuately as well as vertically. A generally straight skeg extends diagonally outwardly from a motor shaft and terminates proximate the motor's propeller.

Abstract: A hydrofoil propeller guard, including a thrust tube, a hydrofoil fin and bottom securing plate, is used in conjunction with an outboard motor mounted on a boat and with stern drives, to encompass the propeller to reduce sideways thrust, to move items away from the propeller, and the guard preferably includes a trolling plate to increase slow speed performance.

Abstract: A lockable propeller guard apparatus 10 including a shroud member 20 having a distal end 22 dimensioned to encircle the propeller 102, a collar member 30 engageable in the distal end 22 of the shroud member 20 and a cover plate member 40 hingedly connected to the collar member 30 and provided with a locking mechanism 45 for securing the cover plate member 40 to the collar member 30.

Abstract: A propeller shroud affixable around the propeller of a water craft. The shroud has a generally cylindrical member which closely surrounds the outer periphery of the blades of the propeller. The front edge of the shroud is deeply concaved to reduce water resistance. Preferably the shroud has several reinforcing blades which are vertically oriented when viewed from the front, but angled rearwardly from the top of the shroud to the bottom. The shroud protects the propeller against damage from rocks, sandbars and the like.

Abstract: An apparatus for locking a propeller is provided for reducing the risk of theft of a propeller from a motor. The apparatus comprises a cover plate to cover an end of the propeller shaft. A U-shaped bar encircling one blade on the propeller and connected to the cover plate secures a portion of the cover plate against the end of the shaft. A locking arm connected to the cover plate, encircling another blade on the propeller, and connected to the middle portion of the U-shaped rod secures the remainder of the cover plate against the end of the shaft.

Abstract: A hydrofoil wing structure is disclosed to be employed as an accessory for a marine propulsion device, to be disposed above and mostly aft of the propelling means of such a device, to contour and concentrate the kinetic energy in the hydrodynamic vortex created by the propelling means; to reduce turbulence, vibration and noise by reflecting acoustic energy downwardly from the surface of the water; to increase the efficiency of such a device powered by an electric battery; to improve the steering and maneuverability of the vessel by providing a rudder for the device; and to serve as a guard preventing the propelling means from entanglement in vegetation or its damage from submerged objects, and to similarly shield a sonar transducer or other instrument used in conjunction with the device for finding fish or gauging the depth of the water.

Abstract: A boat propeller sled comprising a spine, straps attached to the spine, and rails attached to the spine. The straps are sized to fit around an outboard motor lower unit, and to securely attach the spine to the lower unit. Each rail comprises a base attached to the spine, a forward ramp attached to the base, a runner attached to the forward ramp, and a rear ramp attached to the runner. In the preferred embodiment, the bases are attached to the spine at an angle of approximately ninety degrees, the forward ramps slope forward at an angle of approximately sixty degrees relative to the horizon, the runners are substantially horizontal, and the rear ramps slope upwards towards the rear at an angle of approximately thirty degrees relative to the horizon.

Abstract: A guard, particularly adapted to protect a blade of a sailboat rudder from a propeller of an outboard motor mounted on a stern of the boat, includes a mounting plate. The mounting plate has an inner end prepared for ready attachment to a side of a fin of the motor located above the propeller. As attached, the plate then extends laterally toward the rudder to terminate a selective distance beyond outer end tips of blades of the propeller. On an outer end of the mounting plate is a curved protector tube having forward and rear end curved sections which extend respectively toward and away from the boat stern and back toward the motor. During travel of the boat by operation of the motor, the boat is steered by movement of the rudder which selectively positions the rudder blade to effect changes in directions. When rotational movement of the rudder in the direction of the motor is excess, the rudder blade engages the guard protector tube.

Abstract: A marine mammal guard for an outboard motor having a drive shaft housing, an anti-cavitation plate, a lower support unit, a gear casing, a skeg and a propeller hub with a plurality of propeller blades radially thereabout. The guard comprises a protective housing having a pair of forward intake ports and a rearward exit port. A mechanism is provided for securing the protective housing to the lower support unit. The protective housing will extend about the gear casing, the propeller hub and propeller blades below and parallel to the anti-cavitation plate and above the skeg, so as to prevent animals and other objects also submerged within water from coming into contact with the propeller blades of the outboard motor.

Abstract: A propeller protector comprises a shield 18 which surrounds the aft face of the propeller and prevents access thereto. The shield 11 may be secured in position by guide surfaces which engage the lateral fins found on most outboard propeller drive shafts. The protector may be locked in position by a suitable strap.

Abstract: The lower portion of the outdrive of a stern drive motor or of an outboard motor for boats, is further protected from damage on striking submerged objects. Protection at low speed is gained by providing sharp or knife-like edge formed of rubber on the leading of the lower portion to gain the resiliency to cushion from damage at low speeds. Lower portions are typically pivotally mounted with respect to the rest of the motor to enable trim adjustment by a cylinder and piston arrangement. The cylinder and piston arrangement provides some cushion enabling damage-reducing backwards and upwards limited rocking on impact at low moderate speeds. Impact sensing mechanisms conventionally also release the pressure in the cylinder and piston arrangement at low and low-moderate speeds but are generally ineffective at moderate and high speeds to limit damage.

Abstract: A protective enclosure and propulsive system for a motor-driven multi-bladed marine propeller includes a shroud housing which is positioned about the propeller that rotates on its axial through bore, the shroud, providing a safety barrier for the propeller and its underwater enviroment, while also improving the thrust of the propeller by having a converging exit cone containing a horizontal control vane between the sides of this cone, where the cone and control vane both extend rearward of the propeller and at the same negative angle relative to the shroud's centerline.

Abstract: Apparatus for improving the efficiency of a propulsion unit having a driveshaft housing depending from the stern of a boat, while protecting swimmers and the propulsion unit. A plate member has an upper end to be positioned forward of a driveshaft housing and to depend arcuately downwardly and rearwardly to terminate in a trailing lower end below a propeller. The plate member tapers outwardly along lateral edges from the upper end to the lower end to divert swimmers around and under a housing and a propeller attached thereto. The plate member reacts to the passage of water when under way to urge the boat's stern upwardly toward a more efficient operating position. The outer corner areas of the upper and lower ends are connected by outwardly curved rods to define a protection zone to protect body parts of swimmers by diverting them outwardly and downwardly under a propeller.

Abstract: An outboard motor replacement skeg which is thin and flat and has a cavity formed in one of its edges is disclosed. The replacement skeg is slid over the stub which remains after the original skeg is broken off, and is fastened to the skeg stub with silicone sealant and rivets. As an alternative, the replacement skeg may be part of an original design to replace a specific breakaway skeg having a particular mounting structure.

Abstract: A device to protect the propellor of a boat from damage caused by striking underwater obstacles, when the boat is moving in any direction relative to the obstacles, and to improve the movement of the boat along the water.

Abstract: Two angle brackets secure a severely swept plastic wing-like propeller guard to the sides of the motor housing or skeg. The left and right wing-like projections have a horizontal center wing segment oriented parallel the axis of propeller rotation, and upturned outer wing segments that are provided in the plane of propeller rotation.

Abstract: A guard attachable to the lower unit of an outboard motor preventing direct impact between submerged hazards and the elements of the lower unit. The guard includes two angle brackets, a rigid bar attached to the angle brackets at a top end, and a skeg pocket and fin attached to a lower portion of the bar. The guard descends from a position forward of, and substantially level with, the cavitation plate to a point below the skeg. The guard prevents damage to the entire lower unit, including the propeller, upon impact with a submerged obstacle.

Abstract: Apparatus shears foreign matter such as lines, wires, nets and weeds that can entangle and befoul propellers, propeller shafts, bearings and related structures of propeller-driven, water born vessels. The apparatus shears by cooperative action of a rotating blade that rotates in conjunction with the propeller and a non-rotating blade supported on a non-rotating portion of the vessel. The non-rotating blade is supported on a rope guard that encircles the shaft. A system for simplified installation and alignment includes an intermediate box that supports the non-rotating blade. This assembly is temporarily clamped to a rotating blade, with the box passing through an aperture in the rope guard. Then the box is welded to the rope guard at the aperture.

Abstract: An inherently safer propeller design is disclosed. A conventional propeller has a substantially cylindrical ring affixed to the distal ends of the blades. Preferably, the leading edge of the ring extends beyond the forward most extending portion of the leading edges of the blades. The leading edge of the ring is constructed to absorb the energy of impact with an object. In this manner, damage to the object is substantially reduced. The propeller of the present invention presents a design which, in certain preferred embodiments, substantially eliminates the possibility of severe injury when a moving propeller collides with a human or animal. Preferably, the energy absorbing leading edge is comprised of a hollow sheet metal section, which may be foam-filled. Alternatively, the leading edge may be comprised of an elastomer or other material which absorbs energy. Several ways of attaching the leading edge to the ring to create a detachable and replaceable structure are disclosed.

Abstract: An apparatus for automatically raising and lowering boat motors includes a mounting configuration that allows the motor to move up out of the water and down into the water. A hydrofoil is connected with the motor. When the boat is propelled by a second motor, the water pushes up on the hydrofoil, forcing the first motor up out of the water. A locking device can be used to maintain the first motor in the up position. The locking device can be disengaged to allow the motor and hydrofoil to fall into the water. Alternatively, the motor and hydrofoil can be maintained in the up positon by the force of water against the hydrofoil. When the second motor is shut down the motor and hydrofoil automatically drop into the water.

Abstract: Disclosed herein is a propeller guard device, including a laterally extending fin and a vertical extension, or sleeve. The fin and sleeve could be manufactured as a singular item. The vertical sleeve is attached to the midline area of the fin, with the leading edge of the sleeve being generally co-terminus with the leading edge of the fin. The fin is at least as wide as the rotational path of the propeller blades. The singular fin extends laterally on either side of the sleeve in a generally coplanar relationship. The leading edge of the fin is elevated from three to five degrees higher than the trailing edge of the fin. The trailing edge of the fin is located forwardly of the rotational path of the propeller blades, or is lengthened and extends towards the rear of the device to the extent of being even with the midline of the rotational path of the propeller blades.

Abstract: An improvement is provided in a trolling motor of the type having a propeller, a housing with axially spaced leading and trailing ends, a shaft carrying a propeller and journalled for rotation in the housing, and a drive for rotating the shaft and propeller. The housing trailing end has an annular, radially inwardly facing surface and the propeller has a hub with an annular, radially outwardly facing surface on which blades are mounted. The housing, shaft and propeller are mounted relative to each other so that the radially inwardly facing housing surface is radially outside of and in axially overlapping relationship with the radially outwardly facing propeller surface.

Abstract: A replaceable skeg for a marine propulsion device is provided and includes a tapered dovetail tongue and groove joint between top of the skeg and lower portion of a gear case housing on the marine propulsion device. When the skeg is hit by an underwater obstruction it will fracture at the joint and break away, leaving the lower portion of the gear case housing intact and undamaged in which another skeg can be installed thereto.

Abstract: An outboard motor signal made up of a plate-like member bent at right angles at one end as a support and bent at 30 degrees at the other end, whereby the other end is disposed substantially vertical when the outboard motor is in position for transportation, thereby improving the visibility of the signal. A U-shaped spring is provided to hold the plate-like member in place on the motor and reflective tape is disposed on the outside of the plate-like member.

Abstract: In a marine drive (10), a propeller shroud is provided by a cage (24) having internal spoke structure (26, 28, 38, 40, 46, 48) and having retainer structure (50, 74) mounting the cage (24) to the gearcase (12) and engaging the gearcase (12) and driveshaft housing (11) in a particular manner such that impact force on the cage (24) is transmitted to(1) the junction of the lower skeg (20) and the torpedo-shaped portion (14) of the gearcase (12,)(2) the leading edge of the gearcase (12) at the front edge (31) of the strut portion (23) and the front edge (33) of the skeg (20),(3) the underside of the anti-ventilation plate (22), and(4) the rearwardly extending portion (52) of the driveshaft housing (11) above the anti-ventilation plate (22) and the splash plate (13).

Abstract: A weed deflector (28) is provided by a bar (30) mounted to the driveshaft housing (12) of a marine drive (10). The bar (30) has a top portion (46) extending forwardly from the driveshaft housing (12) to a forward leading tip (32) and has a lower portion (38) bent downwardly and rearwardly and tapered back to and mounted to the driveshaft housing (12). The space (34) between the forward leading tip (32) and the driveshaft housing (12) is open so that it does not affect steering of the marine drive (10). The tapered portion (38) of the bar (30) forces weeds to slide downwardly and rearwardly therealong and off of the driveshaft housing (12). The bar (30) prevents weeds from wrapping around the strut portion (14) and covering cooling water inlets (20) or interfering with the propeller (22) or propeller efficiency.

Abstract: A weedguard for attachment to electric trolling motors having a motor housing and a motor support shaft, the weedguard comprising a lower triangular frame member portion and an upper arm portion, the triangular frame portion having a flange for attachment to the motor housing so that the triangular frame portion has one apex toward the front of the motor housing and extends downwardly and rearwardly from the apex with respect to the motor housing; the upper arm portion being secured to the triangular frame portion at that apex and extending upwardly and forwardly therefrom, and a rearward extension member extending from the upper arm portion toward the motor shaft for attachment to the motor shaft.

Abstract: A thin wall sleeve is provided including an inside diameter greater than the outside diameter of the rear terminal end of a marine outdrive lower unit propeller drive housing portion and the adjacent front terminal end of an associated marine propeller hub. The sleeve is mounted in position with its opposite ends telescoped over the housing portion and hub terminal ends and the longitudinal mid-portion of the sleeve bridging the axial spacing therebetween. The sleeve is mounted from the housing portion terminal end, for example, by an adhesive band layer, maintaining the inside diameter surfaces of the sleeve radially spaced outward of the outer surfaces of the housing portion rear terminal end and the hub front terminal end loosely rotatably received within the sleeve.

Abstract: An ice breaker vessel and a method for increasing maneuverability and protecting the propellers against broken ice when going backwards. The ice breaker has two stern propellers and a steering rudder aligned with each propeller shaft. Each of the rudders is individually rotatably mounted on a vertical rudder stock adjacent half the cord of the rubber blade profile length, and connected to a rudder gear, so that they e.g. may converge or diverge in the direction backwards, in abutment with end stops positioned on the stern of the ice breaker vessel, when the rudders are in their respective end positions. The method comprises turning the steering rudders in opposite directions until they cooperate and for backwards converging rudder surfaces.

Abstract: A trolling motor for a boat including collar sections mounting the motor to the boat, a shaft leading from the mounting collar sections to the foot, a foot adapted to be disposed beneath the surface of a body of water, such shaft being hinged along its length such that the foot may swing from its position for propelling the boat toward a horizontal position substantially out of the water when the boat is powered other than by the trolling motor. The foot includes an alignment skeg and deflection shield mounted on the nose of the foot and adapted to urge the foot toward a horizontal position when the boat is moving forwardly under power other than the trolling motor.

Abstract: A propeller protector (26) is provided by a two piece hub structure (28, 30). Each piece has an inner arcuate portion (32, 34) substantially conforming to the side of the torpedo housing (14) of the marine drive. Each piece has a pair of fins (40 and 42, 44 and 46) extending radially outwardly from the inner arcuate portion and spaced axially forward of the propeller (20). Top rear, bottom rear and front clamps (48, 50 and 52) mount the two pieces (28 and 30) to the torpedo housing on opposite sides (36, 38) thereof.

Abstract: This arrangement concerns a flow guide surface for ship propellers, at least for twin propellers, the propellers being mounted by means of propeller brackets. It is provided for to arrange, at least in the region between the arms of the propeller brackets, a sectioned arcuate guide surface. This guide surface possesses a mean camber line converging backwardly towards the propeller shaft and the outlet edge has a distance to the propeller shaft amounting to between 70 and 130% of the propeller radius. This arcuate section of the guide surface is connected, on the side facing the ship's hull, to an approximately horizontal radial part.

Abstract: A flow guide is employed with a marine propeller having blades, and:(a) the guide is substantially cylindrical and has fore and aft opposite ends,(b) the propeller has an axis of rotation, and said flow guide has an axis, said axes being substantially coincident,(c) the flow guide having a rim defining a bore diameter at said aft end which is substantially the same as the propeller blade tip diameter, and(d) the blades having tips and the propeller having a location characterized in that the blade tips rotate adjacent said rim at the aft end of the flow guide. Typically, the guide is mounted to the hull so that the guide axis extends downwardly and rearwardly, at an angle to horizontal.

Abstract: The stern apron is constructed as a volume body tapering to a sharp end in streamlined manner towards the stern of the ship and which at its lower outer edges is in each case wider than in the overlying region, so that the ship's resistance and the necessary propulsive power when travelling in open water is reduced and, particularly when moving astern, the propulsion and control members are protected against contact with the ice.

Abstract: An upper and a lower blade are fixed together at an adjustable angle and have means for mounting same on the leading edge of the propeller drive housing of an inboard/outboard motor to cut kelp and other seaweed which would otherwise foul the prop and clog the cool, sea water input vents. The cutter has adjustable brackets which will accommodate a wide variety of different types of propeller drive housings, and will accommodate outboard motors as well as inboard motors, and will even fit on the advance edge a sailboat keel. In one embodiment, it has a combination brace/mesh screen which extends from the cutter to the propeller drive housing in front of the cooling water inlets to keep bits of seaweed and other debris from entering and clogging the cooling system, causing overheating the destruction of the motor.

Abstract: A propeller guard includes a rigid U-shaped sleeve which has a pair of legs extending on either side of the lower housing in the motor. The cavitation plates on the lower housing are received within a U-shaped channel formed in the sleeve for mounting the guard upon the motor. A cylindrical shield having an open inlet end and an open outlet end is secured to the sleeve and encircles the propeller to protect the propeller from contact with foreign objects. A frame member extends downwardly from the forward edge of the sleeve to the lower portion of the inlet end of the shield and engages the leading edge of the lower housing to provide structural support for the guard. A plurality of horizontally disposed ribs extend from the frame member to the shield to further protect the propeller from contact with foreign objects. A gridwork is pivotally mounted over the open outlet end of the shield to further protect the propeller from contact with foreign objects.

Abstract: An improved trimming arrangement is disclosed which is particularly suited for use with a craft having planing hull with a marine drive. In one embodiment, the trimming arrangement includes a submerged trim hydrofoil which is affixed to the drive housing of the drive system beneath the screw propeller drive shaft. So that the efficiency of the planing hull and drive system are improved at hull-planing speeds, the trim hydrofoil is positioned to create a downward force component of the stern of the planing hull during forward movement through the water. The bow of the hull is thereby urged upwardly, thus minimizing the wetted area of the hull and improving its efficiency. In a further embodiment, the trimming arrangement includes a selectively adjustable submerged hydrofoil pivotably mounted to the transom of the planing hull which is operable to provide the desired downward force component on the stern of the hull.

Abstract: A guard for protection of an outboard motor is described. The guard comprises a main rib with a shock absorbing end portion and a resilient rib which is secured to the main rib such that, when the guard is attached to an outboard motor which is mounted on a boat and which is submerged in water, the resilient rib is disposed forward of the end portion. The forward rib and the end portion extend one behind the other in the direction of travel of the boat so that the forward rib imparts additional shock absorbing properties to the guard. Further shock absorbing resilient ribs and arcuate funnelling bands to strengthen the guard may be secured to the main rib.

Abstract: A spherical vehicle for operation in a fluid medium utilizes an actuator disk or propeller of approximately half the diameter of the sphere for propulsion. In addition to providing the energy for driving the sphere, the actuator disk acts to draw the flow of fluid smoothly over the after part of the sphere, thus avoiding or minimizing the tendency of the flow to separate from the surface of the sphere and create turbulence. For aircraft launch, a heavy shroud protects the actuator disk propeller and assures that the vehicle will sink rapidly after impact. The shroud is jettisoned at a desired depth. Steering in pitch and yaw planes is effected through the use of a plurality of powered thrusters located at or just behind the circle of maximum diameter (with respect to the direction of motion) and selectively actuated by a guidance or control system. Alternatively a single reversible thruster may be used for steering in yaw combined with a movable internal weight for pitch control.

Abstract: A device that shears lines and nets of the type that can befoul propellors, propellor shafts, bearings, running gear and the like of propellor driven, sea-going vessels. A first pair of non-rotatable, diametrically opposed, radially extending cutting blade members are disposed on opposite sides of a keel, or on opposite sides of a strut that depends from the hull of an inboard motor-type boat or ship. Such blade members are provided with respective forwardly extending wedge-shaped projection portions that wedgingly engage respective rearwardly opening wedge-defining base members that are fixedly secured to opposite sides of the keel or the strut. A second pair of rotatably mounted, diametrically opposed, radially extending cutting blade members are disposed on opposite sides of a collar that is affixed to and that rotates conjointly with a propellor shaft, and such second cutting blade members cooperate with the first cutting blade members to effect a shear of troublsome lines and nets.

Abstract: A propeller mount for deflecting ice away from the propeller of an icebreaker includes a wedge-shaped body, the front end of which is pointed, and the remainder of which flares rearwardly to direct ice outwardly away from the propeller assembly. By providing bubblers in the sides of the body near the front end thereof, outward deflection of ice by the mount is promoted. The rear of the body is also slightly wedge-shaped to provide a similr wedging action at the stern for steering ice away from propellers.

Abstract: Propulsion unit for a marine vessel intended for operation under severe ice conditions comprises a multi-bladed propeller, which may be of fixed or controllable pitch, a stationary duct, which may take the form of a nozzle, within which the propeller runs and is protected peripherally against ice damage, and, at the forward and aft ends of the duct, water-guide members in the form of vanes and/or blades which are more massive than is required by their water-guiding functions and which restrict the size of ice masses that can encounter the propeller by entering the duct at its opposing ends. The duct may embrace the propeller peripherally around the full 360.degree.. The water-guide members may be secured at their outer ends to the duct and at their inner ends to ring members co-axial with the propeller. The upper quadrant of the duct may be secured to the hull of the vessel and the lowest portion of the duct to a skeg extending beneath the duct.

Abstract: Disclosed herein is an outboard motor comprising a propulsion unit including a rotatably mounted propeller, structure adapted to be fixedly connected to a boat transom and connected to the propulsion unit for mounting of the propulsion unit for pivotal movement about an axis which is horizontal when the mounting structure is boat mounted, a trim tab mounted on the propulsion unit for pivotal movement about an axis transverse to the horizontal axis, and a linkage for displacing the trim tab about the transverse axis in response to movement of the propulsion unit about the horizontal axis.

Abstract: A tubular duct is provided for ship propellers with blade tips having barrier plates extending transversely therefrom. The tubular ducts are effectively arranged to extend the barrier plates in a manner which, in operation, directs a fluid stream in substantially shock-free contact with such plates.