It has been quite some time since my last post in December 2015 describing a Channel Islands cruise in mid-October. On return from the Channel Islands, I had Baybreeze’s hull slurry blasted down to the gelcoat layer thereby removing multiple layers of crusty antifoul accumulated over a dozen or so years as well as the epoxy GelShield layer (greenish is colour). This was with the intention of coppercoating the hull – a method of more environmentaly-friendly antifouling that, with just one application, protects the hull from barnacles and the like for a period in excess of ten years. The only drawbacks of coppercoating that I am aware of is that it is less effective in keeping at bay the accumulation of vegetable material (green slime!). However, this is easily removed by an annual pressure wash. Perhaps the other drawback is a lack of a choice of colour. Unlike conventional antifoul, coppercoat, although initially copper-coloured, ends up in a bluish-green verdigris colour.
After allowing sufficient time for the hull to dry out after slurry blasting, moisture content readings using a Tramex Skipper Plus Moisture Meter (purchased from Nigel Clegg and Associates) were taken a regular intervals on the hull. Higher readings are indicative of osmosis which, in severe cases and over many years, leads to a chemical breakdown of the fibreglass resin, water retention and blistering! Fortunately, all readings, except for the rudder (which can easily be replaced), were in perfectly acceptable limits indicating that the epoxy GelShield layer had been an effective moisture barrier.
The next stage was preparing the hull for coppercoating. The antifoul and GelShield had to be removed from near the waterline as slurry blasting stopped short of the topsides to prevent any damage to the gelcoat and also from where hull support pads prevented slurry blasting. On the keel, a couple of minor ‘holes’ perhaps a centimetre wide and a couple of millimetres deep, and a few lesser ones, were filled with epoxy filler. The final stage in hull preparation was sanding down the (below-waterline) hull to a uniform smoothness using 800 grit disc on an orbital sander. Try holding a kilogram weight orbital sander above your head for hours on end! Hard work!
The hull was now ready for coppercoating. However, as the uncured coppercoat epoxy is water-soluble, and being outdoors, a rain-free 48 hour window and temperatures, preferably in the teens centigrade to speed up the curing process, were needed. These conditions began to prevail in May 2016 although the first planned attempt had to be aborted as the weather forecast changed for the worse. Eventually, the job was done, the four coats taking two people about 18 man-hours of effort. After a five-day curing period, the supports were repositioned and another weather window was required to coat the parts of the hull where the supports had been – so another couple of weeks delay!
After all the coating had cured, the coppercoated surface was given a light sanding both to expose the copper particles and to smooth the hull surface. The gelcoat topsides at the waterline adjacent to the coppercoat was finely sanded with 2000 grit wet-and-dry sandpaper and the topsides washed and polished.
The removal of the bow thruster propellers proved to be a little more difficult as corrosion had bonded them to the shaft. They were eventually freed by gentle persuasion, and a new anode and coppercoated propellers installed with the shaft generously covered in corrosion protective Lanocote.
Baybreeze was finally launched on Monday 20 June – quite a period on the hard.
Here’s a lovely quote for this post, thanks to LH for drawing it to my attention:
“Houses are but badly built boats so firmly aground that you cannot think of moving them. They are definitely inferior things, belonging to the vegetable not the animal world, rooted and stationary, incapable of gay transition…. The desire to build a house is a tired wish of a man content thenceforeward with a single anchorage. The desire to build a boat is the desire of youth, unwilling yet to accept the idea of a final resting-place.”
from “Racundra’s” First Cruise – Arthur Ransome, 1923.
Next cruise: Ireland and perhaps Scotland’s West Coast.