Surveying Yachts and Small Craft by Paul Stevens

Author:Paul Stevens [Stevens, Paul]
Language: eng
Format: epub
ISBN: 9781472907066
Publisher: Bloomsbury Publishing

ANYONE FOR WOOD?

In case by now you are thinking what a terrible material FRP is, spare a thought for the Owners of the wooden boats in the next series of pictures. Surveying wooden boats is outside the scope of this book but if you encounter FRP hulls with wooden decks and superstructures, always be on the look out for these defects.

Fungal rot

These are the ‘hood ends’, where the hull planking meets the stem at the bow. In Fig A, undulations can be seen in the wood under the paint on the port bow. Fig B shows the results of light hammer sounding on the stb bow. The cell structure of the timber has collapsed and it is completely rotten due to attack by fungal rot.

The news is no better further aft where the rot has spread along the cell structure of the timber. In the top plank in Fig C, you can again see the surface has become concave where the cell structure is collapsing under the film of paint. This kind of rot is very serious and difficult to eradicate. This kind of deterioration in timber can be readily identified by hull sounding, just as when looking for delamination and voids in FRP laminates. When the condition is this advanced, the hammer makes a depressing dull sound and may actually penetrate the timber. In less extreme cases a spike is used gently to test the hardness of areas where the hammer indicates there may be deterioration.

All fungal rot in boats is serious and may be divided into ‘dry rot’ and ‘wet rot’ types, the most dreaded being Serpula lacrymans, or ‘common dry rot’. However, some species of wet rot are equally destructive given the right conditions to flourish; usually damp, warm and dark areas that are common in the deck structures of many boats. The spores for these fungi are air and rain borne, and can thus penetrate these structures where deck leaks occur, so you may come across it in FRP hulled boats with timber decks etc.

In Figs A, B and C, a small, long-term deck leak at the stem has accounted for this pretty east coast centreboarder becoming unseaworthy and uneconomic to repair – all in the space of 16 months.

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