The earliest and most amusing memories of bottom blacking were not on a maintenance basis, but on new boats. Before we moved up to Red Bull in 1972, boats were built in our garden at Norbury. On reflection, for a small village, our long-suffering neighbours must have put up with lots of noise, but one of the quieter stages was when we got on to bottom blacking. We were about a mile from Norbury Junction – which at that time seemed to be the “drop-out” gathering point for students. One of these was Sandra. Sandra lived on various boats, including the horse-drawn trip boat, Iona, which she worked for a while with boyfriend Steve. Sandra used to baby-sit for us a couple of times a week in return for a hot bath and a chance to wash and dry her lovely long hair. One day the question of bitumen and hulls came up and Sandra volunteered to black our new boats before launching. She threw herself into it with great gusto and would appear in ancient and patched boiler suits, with a scarf tied round her hair, which would inevitably escape and land up coated with shiny black bitumen. No bit of the hull would escape Sandra’s attention and she insisted on blacking underneath as well, using a long handled turks head for the tricky bits. She was a sight to behold when she’d finished the job, but must have been our best bottom blacker ever! Sandra eventually married Steve, who’d been studying at the Harper Adams Agricultural College at Newport and they were last heard of farming in the Ellesmere (Shropshire) area.

Things move on, and our move to Red Bull gave us the chance to carry out the regular maintenance on the hulls and learn, over the years, the best way to maintain them.

We were always of the opinion that the hull should be blacked after the first 12 months and then every couple of years. For many years this was done using good old fashioned bitumen. We always kept a record of returning boats to log the changes. The ones which were conscientiously and efficiently blacked, right from the start rarely developed problems, but there were one or two that got neglected and some pitting occurred – these we recommended to go on to blacking every 12 months, until the coming of Comastic!

Comastic is a high build single pack moisture repellent anti corrosive coating for application to boats or steelwork in a marine environment.

We found that there was no further deterioration on the Comastic painted hulls and switched to this for all our boats – offering it as an alternative on our blacking service. The only problem was that the first time, the old bitumen had to be thoroughly cleaned off – not an easy job, but well worth while. This was followed by three coats of comastic below the waterline and two above.

As far a wear goes, the wear edges, (an overhang of steel) clearly shown on the photo’s, were or wear only, not corrosion of course. The areas where they wore away after the years were at the front shoulders, back from the bow and at the stern, level with the end o the swim.

There would be plenty of warning of this and we’d put something like “look at back corners in two years with a view to shouldering” on the boat report. Shouldering is relatively inexpensive and gives many years more life. Shouldering needed at the stern only was generally caused by the boat being too deeply ballasted. Ballasting really matters, both for efficiency and hull wear.

True corrosion shows in pitting and if the boat is inspected at each blacking and any pitting noted, problems can be addressed and the boat treated accordingly. There are one or two things which increase the chances of this corrosion. Mooring by unprotected piles or electrolysis caused by faulty wiring are the most common.

We recently heard from the current owner of Aida – a boat which we built in 1986 for Peter Johnson, who was a stickler for regular maintenance. He was delighted to report that on inspection, the hull is in virtually new condition.

To sum up, Comastic is best for outside the boat, but good old bitumen is best for the inside, due to it’s anti-condensation properties. Check your boat for even wear and don’t skimp on the two yearly blacking programme. Whilst it’s out you can check your prop, sterngear and anodes, if fitted.

by Dot Piper

The original article appeared in Pipeline Summer 08.

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