Ultimate skin fittings
Skin fittings are critical items that keep your boat afloat. However, most are designed to be as cheap as possible to manufacture, with the result that handles rust and, even worse, the critical bits that keep the sea where it belongs are made of thin, low grade materials.
Unfortunately it’s often not been possible to identify the difference between these and marine grade DZR (dezincification resistant) fittings on a chandlery shelf – to an untrained eye they can all look like domestic plumbing fittings. The difference, or course, comes when you immerse them in salt water and the zinc leaches out of the cheaper brass, leaving behind copper in a depleted and weak honeycomb structure.
Since the metal in these fittings is very thin any appreciable amount of dezincification leaves them prone to catastrophic breakage. As a result some boatbuilders recommend replacement at five-yearly intervals – a labour intensive task that could be avoided entirely through using better quality fittings
Fortunately companies, such as ASAP Supplies, sell a selection of resistant fittings of the same pattern made of CW602N CR brass, which address the problems of dezincification. Even better are the through hull fittings produced from Marelon, an engineering composite material, by Forespar and Seaflow. These offer an inert option that will not degrade over time, albeit at a much higher price point. Nevertheless they are excellent products that I’ve been happy to trust for many years.
However, another option is now available thanks to the work of a group of engineers and marine experts who set out to develop the ultimate seacock. Like the Forespar fittings they are more expensive options, but will reduce long-term maintenance costs, as well as minimising risks to the boat, both when at sea and when left on a mooring.
From the outset the developers sought to use top-quality materials and manufacturing processes, as well as an impressive thickness. The result is skin fittings with the potential to last as long as the boat.
The SeaSeal is forged from a traceable DZR alloy. The forging process involves heating the metal until it’s malleable, then hitting it with a 1,000 tonne press to create the required shape. This creates an immensely tough product whose molecular structure is strengthened in the process. The parts are subsequently precision machined to create a high quality finish.
Casting, by contrast, involves fully melting the metal then pouring it into a mould. It’s a process that risks trapping air voids and creates a weaker molecular structure.
Instead of a simple ball valve, as fitted to most boats of the past 40 years, the SeaSeal is a cone valve that operates on a similar principle to a traditional Blakes seacock. However, it has a more sophisticated design. If the cone has become seized due to marine growth, and the bolts holding it in place therefore need to be eased to allow it to be worked back and forth, water won’t flow into the boat thanks to a PTFE seal. Equally, there’s no risk of the cone popping out of its housing. It’s also easy to drain water from the valve when winterising the boat.
Top quality materials are used throughout, with DZR material used even for the handle, so this won’t rust and weaken over time. Manufacturing takes place at TG Stamping & Machining in Birmingham, which has a 70-year history of forging non-ferrous components for critical applications in the gas, oil, fire control and the marine industry. Prices: £145 for ¾in seacock, £205 for 1½in seacock.
seaseal.co.uk