Boating NZ : FREE TO READ March 2014
T he successful restoration of a classic timber boat always reflects huge commitment, financially and in sheer hard graft – and many difficult decisions along the way. Accolades greeted the recent restorations of the launches Ngaio and Waimiga – but the projects also generated considerable debate in the classic boat fraternity. The hot issue was whether or not classic boats should be sheathed in epoxy and fibreglass (epoxy/glass). The sheathing process involves stripping the hull, and sometimes its deck and cabin, back to bare timber and letting it dry thoroughly over several months, while rinsing regularly to remove salt. One to two layers of fibreglass cloth are then laminated over those surfaces with multiple coats of epoxy resin, henceforth described as epoxy/glass. Leaving emotion aside, what are the facts regarding sheathing classic boats in epoxy/glass? Is it, as some claim, a marriage made in heaven to protect elderly classic boats from worms, rot, leaking seams and corroded fastenings? Or, as detractors claim, does sheathing kill boats through kindness? And are there viable alternatives to epoxy/glass sheathing? Over three articles we’ll explore the pros and cons of sheathing classic boats. We'll outline what’s involved in doing it properly and, in the third article, look at viable alternatives to sheathing including new developments in paint technology for classic boats. BACKGROUND Thanks to the training and promotional work by Epiglass New Zealand from the mid-1960s, and Adhesive Technologies (WEST) from the 1980s, sheathing new timber boats in epoxy/glass has become standard practice. Timber boats built from glue- laminated multi-skin or strip planking, with their external surfaces sheathed in epoxy/glass and finished in two- pack paints, are as low maintenance and long lasting as it’s possible to get. However sheathing a traditionally built, carvel planked classic that’s been sitting in saltwater for 50, 60 or more years is a vastly more complicated exercise than sheathing a new, fully-glued timber boat. These difficulties can easily lead to shortcuts. In the long term, a poor sheathing job can create major problems for the boat’s structural health, defeating the reason it was sheathed in the first place. In short, if you cannot sheathe a classic boat properly, don’t do it. As with many boating projects, successfully sheathing a classic boat is largely about preparation: shelter, stripping, drying, salt removal and stiffening. SHELTER Epoxy/glass sheathing a classic boat is virtually impossible to do outside as the extremes of temperature, humidity and wind increase the difficulties exponentially. A stable climatic environment is required, best achieved in a high-stud shed. Timing-wise, sheathing a 10m to 14m classic will take at least four months, although six is probably more realistic and even obtaining a shed for this length of time has its challenges. With the boat set up on stands and well supported along its keel, let’s get into the grunt work. STRIPPING No short cuts here, every surface to be sheathed must be stripped of all paint, which for most classics will mean dealing with red lead and/or antifouling paint. This will mean the full Monty of protective clothing and respiratory protection. Scraping is a proven, labour- intensive method of stripping paint from timber, however an excellent alternative is the X-Foul-E -8 process. This is basically a giant, water- flushed orbital sander, which means no harmful red lead/antifouling dust. Additionally, the water helps flush salt from the timber. However it’s a messy process best done on the hardstand straight after haul out, with the boat being moved into a shed immediately afterwards. Never leave a classic boat outdoors exposed to the sun and wind after this process, as the timbers will dry too quickly. All fittings such as skin fittings, P-brackets and rudder gudgeons will need removing. On yachts, consider dropping the lead ballast keel, which will enable fibreglass sheathing to be carried across the deadwood area. This provides an excellent opportunity to check and replace the keel bolts. If the cabin and decks are to be sheathed, they will need stripping. Ngaio's spline grooves cut to aid drying GLASSINGOVER The X-Foul-E-8 stripping process does a good job of preparing the timber. subscribe online at www.mags4gifts.co.nz/boating-nz 77 subscribe online at www.mags4gifts.co.nz/boating-nz 77 Feature_Fibre glassing_March14.indd 77 18/02/2014 2:16:14 p.m.
FREE TO READ April 2014
FREE TO READ February 2014