Yacht Maintenance & Repair - Part 2: Hull & Deck

This is especially true for GRP yachts as a good polish (or wax) forms a hard and scratch-resistant layer that also protects the original gelcoat from the effects of UV sunlight. With the right treatment, weathered or dull GRP surfaces can also be polished up again, in the literal sense of the word, with astonishing results. There are many special purpose products available at yacht chandleries, for example from Starbrite or 3M (dealer directory and more yacht care tips at www.vonderlinden.de), for the two things that are critical to the care of GRP boats: cleaning and polishing. Smaller boats can still be polished by hand, with soft rags and circular movements, but you don't have to strain your muscles.

Like new
If the ship has been neglected for some years and the surfaces are dull, porous and dirty, you don't necessarily have to repaint the hull completely. Often a particularly thorough cleaning with very fine wet sandpaper of 1500 or 2000 grain in connection with soapy, lukewarm water (mixed with detergent) produces really good results. It removes coarse dirt that has settled in the porous surface. Afterwards you should polish the hull with a boat-, car- or metal-polish. Finally you could apply a hard wax. The rough, porous surface of the gelcoat becomes smooth again because a razor-thin layer (in the hundredth-millimeter range) is removed. It almost looks like new again. And a pleasing side effect: because the surface is now smooth again, it no longer gets stained so quickly or is, at least, much easier to clean.

The waterline
The waterline, which is alternately exposed to water and air as well as to all the dirt floating in the water, should be well sanded and painted with special waterline varnish offered by all large paint manufacturers. Tape cleanly with a specially made adhesive tape, and peel it off immediately after applying the paint. If you leave the tape on the hull overnight or even for a few days, removing it can be quite tedious!

There are other tasks waiting for you on deck. Unfortunately, it is often very dirty due to air pollution and footprints, and it is also much more difficult to clean than the smooth surfaces of the hull. Not only the non-slip profile is a handicap here, but also the many fittings, around which you always have to clean by hand after all.

Be cautious with hairline cracks
One should always pay attention to hairline cracks in the gelcoat, which usually originate more or less star-shaped from a point of particular mechanical stress. This can be a spot on the deck that has been punctually damaged by impact or pressure, or, much more regularly, around fittings such as the feet of stanchions, pulpit or pushpit and sometimes the base of winches. Just anywhere where the area on deck is particularly under pressure and has perhaps even become somewhat soft over the years and is now beginning to buckle. At the beginning this may still be a purely cosmetic problem which some yacht owners like to overlook. But as the cracks get wider, moisture can penetrate the deck's sandwich laminate. This in turn has fatal long-term consequences: Most of the GRP sandwich decks have a core made from balsa wood. It will rot over time when exposed to moisture permanently. The result: the deck as a whole becomes soft, buckles or creaks when you walk on it and will show more and more cracks. There is just one remedy - a complete deck renovation by removing the outer GRP layer, drying the core and renewing it where necessary, and then building up a new laminate over it. This is complex, strenuous and expensive.