Page 14 - Nos conseils

The bête noire of polyester

When should you worry?

On a boat that is a few years old, small blisters do not pose a danger. The blisters are, though synonymous with osmosis. One must intervene. The prevention products that are used for processing small pinheads, or even before they occur though, are often more dangerous than doing nothing. If one applies an impermeable product on a not perfectly dry boat, it can actually accelerate osmosis. On a boat with osmosis (large blisters,) action has to be taken. It is a major
operation that requires peeling the gelcoat and controlled drying of the hull which can take months. When the hull is completely dry apply an epoxy resin based product.

Understanding osmosis

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An indispensable tool for security

Fixed or portable?

The fixed VHF has a maximum power of 25 watts imposed by regulations which limits its range from 15 to 20 miles boat/boat and from 30 to 40 miles toward coastal stations. The new generation of VHF on the market, come equipped with the DSC (Digital Selective Calling) system, ASN (Appel Sélectif Numérique) in French.

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So young and already indispensable!

AIS, what for?

The AIS system, transmits to other vessels, equipped with compatible receivers, information concerning the vessel on which it is installed. Thus is transmitted, the vessel’s identification (MMSI number and name,) its position, course, speed, characteristics (length, width, water displacement,) and possibly information concerning its cargo and destination…All this information is emitted continuously, whether in coastal waters or on the high seas. A vessel which receives an AIS signal can thus visualise the course and speed of the sender and assess the chances of a collision long before it occurs. It is therefore, an invaluable tool for avoiding collisions at sea. This system operates on VHF frequencies (161.95MHz and 162.025MHz.) It is mandatory on all vessels over 300 tons and passenger ships. But many fishing vessels and
even recreational boaters also utilise it. For leisure craft, one may choose to

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Navtex, simple and universal

What Navtex?

The Navtex (Navigational Telex) is an official international system developed in the area of GMDSS, for sailing professionals. The receivers have been developed for leisure craft. They are simple to use and once programmed, will receive bulletins and keep them stored in the memory.
Two types of receptors are proposed: autonomous with LCD screen for reading messages and without screen with a PC output, which connects via a USB port to a computer.

01-03_couverture-navtex

La France possède deux émetteurs (Ouessant au large de Brest et La Garde près de Toulon) qui émettent des messages en français.

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Not yet, “has been”

Chosen according to navigational needs

In coastal Europe, the weather is broadcast, according to the areas and times, on the long wave (LW 150 to 250 KHz), short wave (MW from 530 to 1620 kHz) and frequency modulation (FM 88 to 105 MHz). To capture these frequency bands, a general public receiver is useful. For long range sailing, it is not enough. An MHF-SSB, receiver is a necessity, sensitive enough for fine tuning. Note that some receivers have an output for receiving the Navtex and weather charts on a computer.