Thursday, 25 January 2018

So, Which Ball Valves Are You Using ?

Philmac Ball Valves On Our Seawater Manifold
My story on ball valve replacement at sea (read it here) lead predictably to the question of ball valve construction. Are you a traditional bronze kind of sailor? Or maybe you like stainless steel? Or just maybe you've converted to the newer industrial plastics, made with glass reinforced PVC or Nylon?

On Crystal Blues we love the industrial plastic valves, and have used Philmac ball valves for almost 20 years. These are built for the industrial process and agriculture industries, are tough as nails and (the best part) are cheaper than all those products that have the word marine included in the product description.... still, I understand the Philmac valves are approved for use on commercial vessels in commercial survey in Australia and New Zealand.

Engineered plastic valves are light, strong, do not corrode and won't conduct electricity, all properties that I love. Nowadays there is a new and I believe even higher quality product available - made from glass reinforced PVC. New Zealand company TruDesign make a superb range of tough, precision plastic skin fittings, valves and plumbing components specifically for the marine market. These are sold all over the world, and have certifications from Bureaux Veritas, ABYC, CE and ISO. These are the valves and fittings that will be used on Crystal Blues in the future.

Or Are You Using "Marelon" ?

Glass reinforced plastic valves and fittings are also made using Marelon, principally marketed in the USA by Forespar. Unfortunately these valves have experienced well publicized failures over many years. Marelon is a version of Dupont Zytel, a glass reinforced form of Nylon, a fine structural material, but perhaps not best suited to making marine ball valves, as the base material is weakened by immersion over long periods.  Read The Discussions Here and buyer beware.
TruDesign Diverter Valve

We won't use the Forespar Marelon valves. I should also say that the Forespar Marelon toilet waste diverter valves we purchased never worked properly - the closed outlet always leaked slightly, meaning the holding tank had to be emptied periodically even when not being used.

They were not fit for purpose in my experience. That was an expensive mistake, rectified by refitting with TruDesign diverter valves.


  1. Per Philmac's technical information: the Philmac Blue Handled Ball Valve is identified as N = Not Recommended for Brine solutions. Brine is very similar to sea/salt water. Would guess cheaper cost outweighed any potential risk and manufacture's recommendation.

    1. Actually ...... you better check again! The Philmac product chart has an R for "resistant" in the brine column. Why anonymous? Cheers anyway...


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