FR2739829A1 - DEVICE FOR DRYING THE HULL OF A BOAT, ESPECIALLY A PLEASURE BOAT - Google Patents

Abstract

A device including at least one backing sheet made of a stretchable water-proof material, a water absorbing and retaining substance provided on one side of the backing sheet, and adhesive means for holding the backing sheet and the absorbent substance in close contact with a portion of the hull for as long as it takes the absorbent substance to absorb water from the wall of the hull, and completely sealing off the absorbent substance from the environment around the edges of the backing sheet.

Description

 The present invention relates to a device for drying the hull of a boat, in particular a pleasure boat.

 Several materials used for the construction of pleasure boat hulls have a certain tendency to absorb water. It can be wood, wood-based materials (plywood or molded wood in particular) or polyester resin reinforced with glass fibers.

 This latter material is not in itself impermeable to seawater, which it tends to absorb, and is therefore covered by a semi-permeable and relatively thin sealing layer, called "gel-coat". .

 However, it has the significant drawback of undergoing an inevitable and irreversible phenomenon, called "osmosis".

 Indeed, the layers of glass fibers tend to absorb water through the gel-coat. This water, in particular when it encounters any air bubbles existing between the layers of fabric, comes to hydrolyze the polyester resin. Its concentration increases due to this hydrolysis, and there is a phenomenon of osmosis proper through the gel-coat and the laminated layers. This results in an accumulation of water between this gel coat and these laminated layers, which creates blisters of up to 10 millimeters in diameter.

These blisters are capable of deforming the surface of the shell, since the osmotic pressure exerted can reach five kilograms per square centimeter, to stabilize, after a certain period, at 0.3 kilograms per square centimeter. The accumulation of water can lead to partial delamination of the laminated layers and reduces the mechanical resistance of the material as well as the longevity of the shell.

 The loss of value of a boat undergoing a phenomenon of osmosis is significant.

 The gel coat becomes more and more porous over time, and the risk that the phenomenon of osmosis occurs is all the more important as this porosity increases.

 When the blisters are visible to the naked eye, it is necessary to perform a "curative" treatment of the shell which is particularly long and expensive, this treatment consisting of sanding, planing or sanding the gel-coat and the laminated layers up to '' to update the blisters, to allow the hull to dry for an extended period of time, to put back layers of fabric impregnated with special resin in the places where it was made necessary by sanding, to putty and sand the whole, then apply one or more new layers of waterproofing.

 The natural drying of the shell is very slow, and often requires several months to extend over the hottest and driest period of the year. The boat is therefore unavailable during this period, which is normally the preferred one for pleasure boating.

 Weather conditions, particularly humidity, can slow down and disrupt this drying.

 It is possible to carry out forced drying by wrapping the shell in a tarpaulin and heating the space between the shell and the tarpaulin. However, this method has the disadvantages of being relatively tedious to implement, and of involving close monitoring. The time required for drying remains long, and this drying remains subject to weather and humidity conditions.

 The invention aims to remedy these drawbacks by providing a device which makes it possible to significantly reduce the time necessary for drying, which is insensitive to weather conditions and which is simple and easy to use, in particular by individuals.

 To this end, this device comprises at least one support sheet, made of extensible and impermeable material, provided, on one of its faces, with a product capable of absorbing water and retaining the absorbed water, as well as of an adhesive extending at least along the edges of the support sheet, this adhesive being such that it allows intimately applying the support sheet, and therefore the absorbent product, to all or part of the shell during the time required for the absorption by said absorbent product of the water contained in the wall of the shell, and that it ensures, at the edges of the support sheet, complete isolation of the absorbent product from the ambient medium.

 Thus, the device according to the invention is simply applied to the hull by gluing, and, after a specified time necessary for the absorption of the water contained in the hull has elapsed, is simply removed by detachment.

 The support sheet, thanks to the extensibility of its constituent material, can undergo without tearing or detachment the increase in volume of the product capable of absorbing water, following this absorption.

 The impermeability of this same material makes it possible to prevent any detrimental influence of weather conditions on drying.

 This material can in particular be an extruded polypropylene, with a grammage of the order of 100 g / m2.

 Preferably, the absorbent product is composed of an alginate associated with a weakly hydrolyzed polyvinyl alcohol.

 This product has been found to be perfectly suitable for implementing the invention, and to allow a reduction in the drying time of the order of half compared to the drying time required with the aforementioned forced drying technique.

Advantageously, a cellulose derivative such as an ethyl-methyl-hydrocellulose produced under the trade name of "TYLOSE" by the company HOECHST, or under the trade names of "AQUALON" and "NATROSOL" by the company
HERCULES is added to the absorbent product thus formed, which has the effect of increasing the absorbent power of the latter.

 The adhesive can be applied, during the manufacture of the device, to areas separate from those receiving the absorbent product. It can also be applied directly against the support sheet and receive the absorbent product thereon, in which case the absorbent product is deposited in the form of interrupted zones set back from the edges of the surface of the sheet covered by the adhesive. Alternatively, the absorbent product is applied directly against the support sheet and the adhesive is applied to this absorbent product, in which case the adhesive is porous, and for example consists of a nonwoven of polypropylene type, or has large openings allowing to discover the absorbent product, such as a mesh structure, for example.

 Preferably, the support sheet is dark in color, in particular black, to undergo heating when it is exposed to solar radiation. This heating promotes the evaporation of the water contained in the hull.

 The device can also comprise a reactive product, such as a Cobalt salt or a silica gel, which changes color in the presence of water. A possible change in color of this product provides information on the presence of water in the shell and, depending on the color obtained, allows an evaluation of the amount of water present.

 The device according to the invention can thus be used as a preventive measure to assess whether treatment of the hull is necessary. Advantageously, the support sheet comprises transparent zones opposite the zones comprising this reactive product, in order to allow direct reading.

 When it is necessary to cover a large area of the living works and / or dead works of the hull, the device comprises a set of sheets, preferably in the form of strips, which are applied to the hull with overlapping of a sheet on the other.

 Certain support sheets, or all of them, may comprise, at least along one of their longitudinal edges, an adhesive and waterproof strip, of relatively small thickness, making it possible to form an anti-drip protection at the level of their edge most exposed to weather and runoff. Any risk of water infiltration is thus eliminated.

 For local treatments, the device can adopt any shape appropriate to the surface to be treated, in particular circular for application around a through-hull or in a strip for application along the waterline.

Claims (10)

 1 - Device for drying the hull of a boat, in particular a pleasure boat, characterized in that it comprises at least one support sheet, made of extensible and impermeable material, provided, on one of its faces, with '' a product capable of absorbing water and retaining absorbed water, as well as an adhesive extending at least along the edges of the support sheet, this adhesive being such that it makes it possible to apply intimately the support sheet, and therefore the absorbent product, on all or part of the shell for the time necessary for the absorption by said absorbent product of the water contained in the wall of the shell, and which it ensures, at level of the edges of the support sheet, complete isolation of the absorbent product from the ambient environment.  2 - Device according to claim 1, characterized in that the material of the support sheet is an extruded polypropylene, with a grammage of the order of 100 g / m2.  3 - Device according to claim 1 or claim 2, characterized in that the absorbent product is composed of an alginate associated with a weakly hydrolyzed polyvinyl alcohol.  4 - Device according to claim 3, characterized in that a cellulose derivative such as an ethyl-methyl-hydrocellulose produced under the trade name of "TYLOSE" by the company HOECHST, or under the trade names of "AQUALON" and " NATROSOL "by the company HERCULES is added to the absorbent product.  5 - Device according to one of claims 1 to 4, characterized in that the support sheet is dark in color, in particular black.  6 - Device according to one of claims 1 to 5, characterized in that it comprises a reactive product, such as a Cobalt salt or silica gel, changing color in the presence of water.  7 - Device according to claim 6, characterized in that the support sheet comprises transparent areas opposite the areas comprising the reactive product.  8 - Device according to one of claims 1 to 7, characterized in that some support sheets, or all of them, comprise, at least along one of their longitudinal edges, an adhesive and waterproof tape , of relatively small thickness, making it possible to form an anti-runoff protection at the level of their edge most exposed to the weather and to runoff.  9 - Device according to one of claims 1 to 8, characterized in that it comprises a set of sheets, preferably in the form of strips, which are applied to the shell with overlapping of one sheet on the other.  10 - Device according to one of claims 1 to 7, characterized in that it has a circular shape, for application around a through-hull, or in a strip, for application along the waterline.