Rupert Holmes explains how to strongly attach new or replacement fittings to decks – and how to fill redundant old bolt or screw holesAdding deck fittings is a task long-term boat owners will invariably have faced many times. If the deck is cored where the fitting will be, you need to remove some of the core around the bolt holes. Backing platesLoads from deck fittings need to be spread over a wide area, otherwise there’s a risk of the bolts simply pulling through the deck. For this purpose, although Zest has a big aluminium backing plate below the deck fitting, there’s also a Dyneema strop taken down to a strongpoint bolted through the stem. However, these products are available with different levels of adhesion – Sikaflex 291 and 3M 4400, for instance, have a low level for use with general deck fittings, while Sikaflex 292 and 3M 5200 have a high level.