Boating NZ : FREE TO READ April 2014
subscribe online at www.mags4gifts.co.nz/boating-nz 67 Pennington also pre-primes with resin, which he covers in peel ply. The next day the peel ply is removed and the actual sheathing is carried out using multiple layers of fibreglass. Beck says both methods are valid; the key is to get sufficient resin into the hull for adhesion, but not so much that the fibreglass floats off. The fibreglass cloth should be overlapped rather than butted at the edges, and ideally will overlap the hull bottom across the keel/ deadwood area. At the top of the hull, the fibreglass edge should be finished where it can be covered with a toerail or rubbing strip to protect the more vulnerable edge. When sheathing decks and cabin, carry the fibreglass down onto the hull sheathing, or finish the edge where it’s later covered by a toerail, rubbing strip or similar detail. PAINTING After sheathing, a classic is usually spray-painted with a two-pack paint system, a process well described in paint supplier literature. The key issue here, specific to classics, is paint colours. Some epoxy/glass-sheathed classics, including Ngaio and Waitangi, have been painted in dark colours. While this can look stunning, dark colours absorb heat, which increases surface temperatures. Standard epoxy resin becomes rubbery at around 60 C, which can result in print-through where plank seams, fastening holes and even the fibreglass weave shows in the paint surface. While print-through is essentially a cosmetic issue, in some cases temperatures have got so high that the sheathing can partially delaminate from the timber. Many experts feel painting an epoxy/ glass sheathed classic in dark colours is risky. Some owners are prepared to accept this risk; anyone remotely risk-averse is advised to stick to light colours. SEALING With the exterior now fully sealed, it’s time to stabilise and waterproof the interior, otherwise bilge water can soak into the planking, which will swell and become dimensionally unstable. In extreme cases, the planking can pull off the frames or crack the sheathing along the plank seams. Ideally, Beck says the entire interior should be stripped and sealed with multiple coats of epoxy resin. If the classic boat has been completely gutted, it’s relatively easy to seal the interior, but if the interior cabinetry is to be retained it’s almost impossible to do properly. In that case, as a minimum Beck recommends the interior be cleaned, sanded and thoroughly painted. Additionally, it’s important to deal with any potential leaks to ensure the bilges stay dry. For example, old-style stern glands should be replaced with a dripless type, and the likes of cockpit and deck drains arranged so that rainwater is channelled overboard and not into the bilge. FINANCIAL An epoxy/glass sheathing job is labour intensive and, if carried out professionally, will be expensive. Assuming no major structural issues are encountered, indicative prices to professionally sheathe an average 12m classic boat range from $30,000 to $45,000. A professional, spray-applied, two-pack paint job will be extra to the sheathing costs. While this will be less expensive than for a stand-alone spray paint, because much preparation work will have been done during the sheathing, painting is still likely to cost another $15,000 to $20,000. So a professional sheathing and two-pack paint job on a 12m classic will lighten its owner’s wallet by somewhere between $45,000 and $65,000. These estimates exclude GST. Sadly the secondhand market won’t value epoxy/glass sheathing at anything approaching these costs, so an owner selling a sheathed classic within five to 10 years will be out of pocket. On the other hand, should the owner keep his or her classic for a decade or two, a decent epoxy/glass sheathing job will likely pay for itself in reduced maintenance. SUMMARY Hopefully these two articles have provided those interested in sheathing classics in epoxy/glass an appreciation of what’s involved. There’s no middle ground with sheathing: do it properly or don’t do at all. Depending on the boat’s condition and required outcome, there are alternatives to epoxy/glass sheathing, to be discussed next month. We’ll also examine how to get more life from traditional, single-pack paint systems, plus a recent development in paint technology which holds considerable promise for classic boats. 24 Bay Rd, Invercargill. Ph: 03 214 4573 Fax: 03 215 9177 Mob: 0274 368 055 Email: email@example.com .nz Now is the time to book your space for your own customised boat and contact us for a boat test. 0414-570414-18 REGULAR_PB_fibreglass PTII_April14.indd 67 18/03/2014 5:27:45 p.m.
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