Next post will focus on Envoy's cruising plans for 2013.
In Europe, because of a spate of corrosion related valve failures, a standard has been established that calls for valves made of the appropriate alloy to be embossed with the letters DZR, which stands for 'dezincification resistant'. Look for this on any metallic valve or seacock used with raw water and offered in the EU.
Among the most common defects related to seacock installation is the use of non-compatible threads. Common through hull or skin fittings rely on straight, parallel or NPS threads, while most common in-line valves utilise tapered, cone-shaped or NPT threads. While the two can be forced together, they typically seize after just two revolutions, offering very little engagement. While it seems obvious that one would not make such a union between to clearly incompatible threads, it's done on a regular basis by boat builders, boat yards and do-it-yourselfers. I encounter it constantly, and the practice is often vehemently defended by those who practice it; rest assured, it violates the most basic principles of engineering as well as ABYC guidelines and those of many manufacturers. True seacocks on the other hand, utilize NPS or straight threads that are designed to properly engage those of through hull fittings.
Well-known and respected marine technical author Steve D’Antonio reviewed the last two posts re seacocks and added the following additional information.
Ideally, any seacocks obtained in the US should comply with ABYC H-27, which in turn requires compliance with ANSI/UL 1121. Be careful, however, just because a valve says "UL" on it, does not mean that it is UL 1121, the latter being the designation for "SEA VALVES" and not simply any ordinary valve.In Europe, because of a spate of corrosion related valve failures, a standard has been established that calls for valves made of the appropriate alloy to be embossed with the letters DZR, which stands for 'dezincification resistant'. Look for this on any metallic valve or seacock used with raw water and offered in the EU.
Among the most common defects related to seacock installation is the use of non-compatible threads. Common through hull or skin fittings rely on straight, parallel or NPS threads, while most common in-line valves utilise tapered, cone-shaped or NPT threads. While the two can be forced together, they typically seize after just two revolutions, offering very little engagement. While it seems obvious that one would not make such a union between to clearly incompatible threads, it's done on a regular basis by boat builders, boat yards and do-it-yourselfers. I encounter it constantly, and the practice is often vehemently defended by those who practice it; rest assured, it violates the most basic principles of engineering as well as ABYC guidelines and those of many manufacturers. True seacocks on the other hand, utilize NPS or straight threads that are designed to properly engage those of through hull fittings.
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