GB2091662A

GB2091662A - Anti-fouling boat water-intake

Info

Publication number: GB2091662A
Application number: GB8102168A
Authority: GB
Original assignee: Individual
Current assignee: Individual
Priority date: 1981-01-23
Filing date: 1981-01-23
Publication date: 1982-08-04
Also published as: GB2091662B

Abstract

The water inlet holes in a boat water-intake are kept substantially free from fouling or incrustation by marine organisms by being disposed in a block 6 of material which is highly electro-positive to that material which provides the other metallic immersed components of the boat. <IMAGE>

Description

SPECIFICATION Anti-fouling boat water-intake The traditional method of providing for cooling of the engine and exhaust gases in a boat used for fishing or pleasure, is by drawing water from the river or sea into the water cooling ducts of the engine through a water-intake sealed into the boat hull below water level. In the case of a conventional drive, in which the propellor shaft projects at a small angle with the horizontal, the water-intake is usually a special fitting which is sealed through the hull of the boat separately from the engine or drive shaft. Recent practice however is for the propellor unit to be housed at the end of a drive-leg which extends downwardly through the hull, as in the so-cailed 'Saildrive' or 'L-Drive' principle, where the water-intake forms part of the drive-leg, through which the water is led through a duct, to the engine.The water-intake plate or block consists of material with a number of small holes, through which the water can flow, but through which large objects cannot gain ingress into the engine cooling ducts, such as might lead to a restriction of flow were they to become wedged in the cooling ducts.

Under adverse conditions, however, these small water access holes will become fouled by weed, or encrusted by marine animal life (e.g. Barnacles), with the result that the water-intake in a prolonged period of dis-use may become so encrusted that water flow is inhibited to such an extent that the engine can be seriously overheating, and a fire hazard ensues.

It is the object of the present invention to provide an arrangement of the water-intake that is fundamentally of an anti-fouling nature, by adopting such a suitable combination of materials as to inhibit the formation of plant or animal colonies within the water-ways.

It is well known in the art that a combination of dis-similar metals in electrical contact, and immersed in water, other than distilled, will display electrolytic action, such that material tends to become eroded from the more electropositive metal and deposited upon the less electro-positive metal. This principle is frequently employed to prevent corrosion of an important structure of a boat, by providing a block of a more eiectro-positive metal adjacent to it, called the anti-corrosion anode. This phenomenon, leading to the erosion of one such metal creates conditions close to the surface of the metal which are unfavourable for the growth of plant and animal life in the water, and thus the amount of fouling locally to the electro-positive area relative to the adjacent areas is reduced.

Thus, if the water-intake plate or block is composed of a material which is more highly electro-positive than the main bulk of metal locally, the water-intake will remain clean and not become fouled for a longer period of time than if it were of the same material of which the bulk of the adjacent metal were composed. For convenience, the water-intake plate or block may also be employed in place of the normal anti-corrosion anode.

The same principle can also be introduced to provide anti-fouling properties on any other waterintake which may be required on the boat, or on a boat which does not need water cooling for the engine.

The invention will now be described in detail, referring to a number of embodiments. However these are not to be taken as representing either in part or in full the totality of the invention, which is described fully in claims appended hereto.

In one embodiment of the invention, shown in figures 1 and 2, the engine of a boat with conventional drive arrangements (1) which is connected to the drive shaft and propellor (2), through watertight seals through the boat hull (3), is provided with water for cooling purposes through the water-intake (4) comprises a flanged pipe sealed through the hull (5), which is provided with an intake block (6) composed of a more highly electro-positive metal, which is removably fixed to it. This block is of substantial dimensions, adequate to provide anodic protection for the main areas of metal exposed to the water on the boat.The table of metals in order of electropositive characteristics is well known to Naval Architects, and suitable metals can be selected to suit the characteristics of other metallic structures below water-level, however, where there are no other metallic structures, the metals might be selected as - for the flanged pipe, Bronze, and for the water-intake block, Zinc.

In another embodiment, for the case of an engine driving the boat through a 'Saildrive' type of Drive leg, according to Figure 3, the water for cooling the engine is provided through ducts cast into the drive-leg casing (11), and the waterintake block (1 2) is removably fixed to it, for example by screws compatible with both of the materials used. In this case, the casing of the Drive leg might well be of cast Aluminium, in which case, the Water-lntake and anti-corrosion block might well be either of Zinc or Magnesium.

Having thus described the invention with respect to the embodiments described above, I claim it to be described in full in the claims listed in the attached sheet.

1. An arrangement for providing water supply for engine or other purposes on a boat, by drawing it from below the water line, in which the waterintake consists of a removable block or plate which is inherently capable of repelling fouling or incrustation by marine organisms by being made of a material, such as a metal or alloy, which is highly electro-positive with respect to the surface to which it is attached and which provides the access for the water supply between the waterintake block and the interior of the boat hull.

2. An arrangement as claimed in the foregoing claim, in which the water-intake plate or block also provides the function of an anti-corrosion anode, which protects other immersed metal parts

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Anti-fouling boat water-intake The traditional method of providing for cooling of the engine and exhaust gases in a boat used for fishing or pleasure, is by drawing water from the river or sea into the water cooling ducts of the engine through a water-intake sealed into the boat hull below water level. In the case of a conventional drive, in which the propellor shaft projects at a small angle with the horizontal, the water-intake is usually a special fitting which is sealed through the hull of the boat separately from the engine or drive shaft. Recent practice however is for the propellor unit to be housed at the end of a drive-leg which extends downwardly through the hull, as in the so-cailed 'Saildrive' or 'L-Drive' principle, where the water-intake forms part of the drive-leg, through which the water is led through a duct, to the engine.The water-intake plate or block consists of material with a number of small holes, through which the water can flow, but through which large objects cannot gain ingress into the engine cooling ducts, such as might lead to a restriction of flow were they to become wedged in the cooling ducts. Under adverse conditions, however, these small water access holes will become fouled by weed, or encrusted by marine animal life (e.g. Barnacles), with the result that the water-intake in a prolonged period of dis-use may become so encrusted that water flow is inhibited to such an extent that the engine can be seriously overheating, and a fire hazard ensues. It is the object of the present invention to provide an arrangement of the water-intake that is fundamentally of an anti-fouling nature, by adopting such a suitable combination of materials as to inhibit the formation of plant or animal colonies within the water-ways. It is well known in the art that a combination of dis-similar metals in electrical contact, and immersed in water, other than distilled, will display electrolytic action, such that material tends to become eroded from the more electropositive metal and deposited upon the less electro-positive metal. This principle is frequently employed to prevent corrosion of an important structure of a boat, by providing a block of a more eiectro-positive metal adjacent to it, called the anti-corrosion anode. This phenomenon, leading to the erosion of one such metal creates conditions close to the surface of the metal which are unfavourable for the growth of plant and animal life in the water, and thus the amount of fouling locally to the electro-positive area relative to the adjacent areas is reduced. Thus, if the water-intake plate or block is composed of a material which is more highly electro-positive than the main bulk of metal locally, the water-intake will remain clean and not become fouled for a longer period of time than if it were of the same material of which the bulk of the adjacent metal were composed. For convenience, the water-intake plate or block may also be employed in place of the normal anti-corrosion anode. The same principle can also be introduced to provide anti-fouling properties on any other waterintake which may be required on the boat, or on a boat which does not need water cooling for the engine. The invention will now be described in detail, referring to a number of embodiments. However these are not to be taken as representing either in part or in full the totality of the invention, which is described fully in claims appended hereto. In one embodiment of the invention, shown in figures 1 and 2, the engine of a boat with conventional drive arrangements (1) which is connected to the drive shaft and propellor (2), through watertight seals through the boat hull (3), is provided with water for cooling purposes through the water-intake (4) comprises a flanged pipe sealed through the hull (5), which is provided with an intake block (6) composed of a more highly electro-positive metal, which is removably fixed to it. This block is of substantial dimensions, adequate to provide anodic protection for the main areas of metal exposed to the water on the boat.The table of metals in order of electropositive characteristics is well known to Naval Architects, and suitable metals can be selected to suit the characteristics of other metallic structures below water-level, however, where there are no other metallic structures, the metals might be selected as - for the flanged pipe, Bronze, and for the water-intake block, Zinc. In another embodiment, for the case of an engine driving the boat through a 'Saildrive' type of Drive leg, according to Figure 3, the water for cooling the engine is provided through ducts cast into the drive-leg casing (11), and the waterintake block (1 2) is removably fixed to it, for example by screws compatible with both of the materials used. In this case, the casing of the Drive leg might well be of cast Aluminium, in which case, the Water-lntake and anti-corrosion block might well be either of Zinc or Magnesium. Having thus described the invention with respect to the embodiments described above, I claim it to be described in full in the claims listed in the attached sheet. CLAIMS

2. An arrangement as claimed in the foregoing claim, in which the water-intake plate or block also provides the function of an anti-corrosion anode, which protects other immersed metal parts of the boat from electrolytic corrosion.

3. An arrangement as claimed in either of the foregoing claims in which the water-intake is separate from other immersed metal parts of the boat, and itself consists of both the highly electropositive and the less highly electro-positive elements.

4. An arrangement as claimed in any of the foregoing claims, in which the water-intake plate or block is maintained in electrical contact with the less highly electro-positive element, either by virtue of its construction, by the metal surfaces being maintained in intimate contact, or by a separate electrical connection, provided for that purpose.

5. An arrangement as claimed in any of the forementioned claims, in which the water-intake plate or block forms a part of the metal structure of the boat, or of the drive-leg by which the boat is propelled, and in which the water supply is taken into the interior of the boat hull through water tubes or ducts formed within the metal structure.

6. Any arrangement substantially in accordance with any of the drawings attached to this application.