Snow load on the winter cover

Owners who store ashore in Scotland, Scandinavia or anywhere inland underestimate snow, because a cover looks like a roof and a roof sheds what falls on it. Wet snow reaches 400 kilograms per cubic metre. Twenty centimetres of it over a ten metre boat is more than a tonne sitting on a structure built from battens and a few props. What fails first is rarely the fabric. The ridge bends, the frame folds inwards, the cover tears where it is stretched, and water runs straight into the cockpit and down below, where it does more damage than the snow ever did.

Two clauses decide how a claim like that is handled. The first is the period of cover, because a policy sold for the season only tends to end when the boat leaves the water, which is exactly when this risk starts. The second is how consequential damage is treated, meaning the water that follows once the cover has torn, which usually costs far more than the cover and the frame together. If the boat overwinters in a shed, remember that the building belongs to someone else and is insured by them, while your boat is not. In our wording the weight of snow on its own is a weather influence and not insured. What is covered is damage from storm, in Basis from force 8, even where the storm tears a loaded cover, and fire in the shed. With our season policy there is no cover from 1 November to 31 March.

There is also a duty that no policy takes off your hands: to limit the damage once it is foreseeable. During prolonged snowfall you are expected to clear the cover or to instruct somebody to do it, and an owner who keeps the boat several hundred miles from home should put that instruction to the yard in writing rather than hope. A common mistake is a flat cover with no ridge and no fall, so the snow stays where it lands. A proper pitch and a few extra supports cost very little and prevent most of these claims.

Worth remembering

The fabric is not what fails. The structure holding it up is.