Capsize and sinking of various 'double-skinned' dories
September 1999
Issue
The circumstances leading to the incidents varied but a common factor proved to be the existence of water in the cavity between the 'deck' and the 'hull'. Expandable foam in the cavity in some cases proved to be water-logged. The result was a rapid and progressive loss of stability leading to capsize.
Outcome
Several methods of detecting water in the supposedly sealed cavity have emerged.
- Keep an eye on the 'normal water level' - does it move over time? Is it level?
- Listen for 'sloshing' sounds if and when the boat is brought ashore.
- Some providers weigh the boat at the start of the season (when it is known to be dry) and periodically re-weigh it during the season.
- Drill some drain holes which can later be repaired. This is a skilled job, but is probably the only reliable way of getting water out once you've found it. Use someone who knows what they are doing.
- Regularly check for damaged or missing fittings, cracks in the hull or deck etc. As with day boats, you may wish to use scenario based exercises to capsize it but be careful. They can 'flip' very suddenly - extra personal protection may be appropriate.
Once inverted see if there is anything for survivors to:
- Hold on to, or should some form of 'grab rope' be fitted?
- Get caught on, if so, should it be removed?
