sailing

A Life Changing Odyssey

December 3, 2013

By David Skelhon

Thirty years ago I quit my job in science and engineering. Even in my late 20’s I was tired and disgruntled with the world and my place in it. I wanted to get off the treadmill, and experience the beauty of Planet Earth, or at least my little corner of it.

With my partner at that time, Jill Brown, we looked to the world of sailing for travel and adventure. We sold our home, built a small Polynesian-style catamaran and moved to the ocean. We struggled to make a living in Cornwall, one of the most beautiful counties in the British Isles. I built boats and wrote books and magazine articles. It took a few years but the dream eventually became reality and culminated in an extraordinary voyage around the west coast of Britain in the summer of 1990.

Suilven’s Travels: A Life Changing Celtic Odyssey is my account of this 3 month cruise which was packed with adventure and challenge. Suilven II departed Plymouth in July and headed to the Hebrides, stopping in Scilly, Wales, the Isle of Man and Northern Ireland. The story brings to life the landscape and culture of western Britain and in particular Scotland’s Inner Hebrides. It also shows what is possible on a minimal budget if the desire to succeed is strong enough. I was alone for most of the outbound trip, giving me plenty of time to reflect on the world and my place in it. Jill Brown was with me on the demanding return trip when we struggled against gales and rough seas and came close to losing our small boat on a couple of occasions.

Looking back nearly 25 years it’s obvious there has been dramatic change in our world – especially in technology. But the human spirit and the search for meaning in life is growing stronger as more of us realize it is becoming impossible to thrive in a system which essentially alienates us from our Earth, and our true selves. Suilven’s Travels was written to inspire others to step outside the box and live closer to the Earth. It is available for $3.99 as an eBook on Amazon, in multiple formats on Smashwords and will be available at many other outlets soon.

Stopping Barnacle Build-Up on Propellers

September 27, 2013

Boat Maintenance, sailing, Wooden Boats

2 Comments

Applied as a spray, Pettit claims Zinc Coat Barnacle Barrier will protect propellers from barnacle build-up.

I still haven’t figured out why the bronze propeller on my boat is the first thing to become encrusted with barnacles after a haul-out. After all, the main constituent of bronze is copper, and my Pettit Horizons antifouling is loaded with copper and it does its job very well elsewhere. But propellers are generally left bare, probably because modern ablative coatings wouldn’t last long due to the high velocity flow across the spinning blades.

Strictly speaking, my prop is probably a manganese bronze which really makes it a brass. Are you confused yet? Well, a brass is an alloy primarily between copper and zinc, typically with 60% copper. True bronzes are usually an alloy of copper with silicon or (now less common) tin. Brass is an inexpensive alloy and very easy to cast into intricate shapes. Unfortunately in a marine environment brass is very susceptible to corrosion and that’s one reason why a small amount of manganese is added. The zinc and copper are not a homogenous mix. Zinc rich areas are electropositive relative to the copper rich areas and consequently zinc dissolves from the surface by electrolysis in the zinc rich areas.

If your freshly polished propeller has a blotchy pink appearance than it is likely to have already suffered some “dezincification.” Some of the zinc has gone leaving a weak, spongy copper rich areas. This can eventually lead to structural failure. That’s why propellers should have some form of galvanic protection, typically in the form of a zinc anode attached to the shaft.

Rainbird’s propeller shows signs of dezincification.

In spite of these areas being copper rich, they are still prone to marine fouling, which is perplexing. Perhaps copper in antifouling is just more readily available to prevent fouling.

I normally polish the propeller with a fine abrasive and leave it untreated. At a recent haul-out, the boat yard suggested that I try Pettit’s Zinc Coat Barnacle Barrier to prevent barnacles growing on my propeller. This comes in a spray bomb and the instructions recommend 3 coats applied one hour apart. This is easy enough. So why would zinc work as an antifouling? The zinc in my prop obviously doesn’t do the job so why should I expect this to work? Once again, maybe it’s availability, and as the yard pointed out, when was the last time I had seen fouling on a zinc anode?

Time will tell if this is an effective solution and I’ll keep you posted.