1. Field of the Invention
This invention relates to a marine life growth inhibitor device for inhibiting marine life growth on the submerged outer surface of a submerged article.
2. Description of the Prior Art
The problem of marine growth on submerged articles has long been recognized in the art. Particularly bothersome are organisms known as barnacles, which tend to attach to and/or deposit heavy calcium-like encrustations on boat hulls, screws, rudders, and virtually any submerged article. Of course, it is obvious that when barnacles attach themselves to the hull of a ship or boat, their presence materially detracts from the performance of the vessel. In recognition of the many problems created by the growth of barnacles on submerged ship surfaces, numerous devices and procedures have been devised for preventing such barnacle growth.
Perhaps the most well known method of preventing barnacle growth is the use of special paints or coatings on submerged boat surfaces. Some such coatings actually serve to halt barnacle growth for relatively short periods of time, while other less expensive such coatings merely slow the growth. Regardless of the particular type paint or coating utilized, certain inherent limitations have been observed. First, the boat must be completely removed from the water so that all submerged surfaces can be properly coated. Second, the coating is easily removed. While it is obvious that striking a submerged object would tend to chip and dislodge portions of the coating, it should also be noted that simply the friction of water rushing past the ship's hull will in time remove the coating. In recognition of the self-imposed limitations of paints and coatings, more sophisticated devices have been devised for preventing fouling of submerged articles by barnacle growth.
One such device is disclosed in U.S. Pat. No. 3,309,167, relating to an anti-fouling apparatus. That patent discloses an apparatus which prevents fouling of underwater equipment by heating the submerged external surface. According to the disclosure of that patent, barnacles cannot endure a temperature of over approximately 95.degree. F. It is therefore the purpose of the apparatus of the patent to provide means whereby the boat's hull may be heated above that critical temperature. Of course, it should be obvious that such a device must be carefully installed, because surfaces of the boat are being heated, and those surfaces ae often in close proximity to the boat's bilges. This necessarily presents a fire hazard should any oil settle in those bilges.
U.S. Pat. Nos. 3,650,924 and 3,661,742, each relate to electrolytic methods for preventing fouling of ships by barnacle growth. Basically, each of these patents disclose an apparatus and method whereby sea water may be electrolyzed, and the decomposition products are discharged along the side of the ship. In U.S. Pat. No. 3,650,924, compressed air is also discharged along the sides of the ship so as to form a dense air blanket holding the electrolysis decomposition products adjacent the side of the ship. While both of these methods appear to be quite successful in controlling or preventing barnacle growth, it should be obvious that their installation would be limited to relatively large ships because of their complexity and cost. Additionally, both these methods require substantial maintenance, because the electrolysis decomposition products must be maintained along the surface to be protected.
Yet another method for preventing barnacle growth is disclosed in U.S. Pat. No. 3,837,916. That patent discloses the method of supplying fresh water on the surface of the submerged article to be protected. The barnacle organisms simply will not grow in the presence of fresh water, but such a method would seem extremely impractical for a large surface. While it would no doubt eliminate the growth of barnacles, to protect the entire submerged hull of even a relatively small fishing boat would require huge quantities of fresh water.
The use of vibration on a boat hull is disclosed in U.S. Pat. No. 2,366,162 and British Pat. Nos. 703,158 and 719,650. These patents teach the use of ultrasonic or supersonic vibration applied to the hull of the boat for causing various beneficial affects.
Accordingly, it is obvious that there is a need in the boat and ship industry for an apparatus and method of inhibiting marine life growth on submerged surfaces which is efficient, simple to install and maintain, and economical to operate. Such a device should preferably be of a type suitable for use on small fishing boats as well as large ocean-going vessels. It should also be capable of use and maintenance by the boat owner, only infrequently requiring technical adjustment and repair.
Therefore, it is an object of this invention to provide a marine life growth inhibitor device for use in combination with a boat hull comprising vibrator means including a speaker and a speaker housing adapted for directing acoustical energy from a speaker diaphragm to the inside surface of the boat hull to inhibit the growth of marine life on the exterior surface of the boat hull.
Another object of this invention is to provide a marine life growth inhibitor device for use in combination with a boat hull incorporating speakers adapted for transfer of acoustical energy in substantially only the audible range of frequency.
Another object of this invention is to provide a marine life growth inhibitor device for use in combination with a boat hull including a plurality of speakers electrically connected in series for terminating operation of the plurality of speakers upon an open circuit occurring in any one of the plurality of speakers.
Another object of this invention is to provide a marine life growth inhibitor device for use in combination with a boat hull comprising a speaker mounted in a speaker housing to enable constructive interference between acoustical energy propagating from the first and second sides of the diaphragm of the speaker.
Another object of this invention is to provide a marine life growth inhibitor device for use in combination with a boat hull including a speaker housing having a first and a second speaker housing portion with one of the housing portions having a housing diaphragm therein for enabling transfer of acoustical energy from a speaker mounted within the speaker housing to the hull of the boat.
Another object of this invention is to provide a marine life growth inhibitor device for use in combination with a boat hull including a speaker housing mountable to the inside surface of and below the normal water line of the boat hull and forming a water repellant speaker housing.