Explosion of a inflatable boat

The boat was a 6.5 m semi-rigid electric-powered inflatable canoe, mainly used for greeting and directing pleasure boaters in harbour.
It exploded without a flame shortly when an employee of the harbour master's office turned on the ignition after unplugging the batteries. The back of the boat was projected into the air, together with the employee, which was hospitalised. The boat was completely destroyed.

Purchased three months before, this boat was one of the three pre-series prototype boats
in service in marinas. The responsible authorities were alerted and the use of these canoes was suspended.

According to the ARIA report (see references), the manufacturer and an independent third party performed expert assessments before the divers re-floated the canoe. Apparently, the reason of the explosion was the hydrogen emitted from the dry batteries of the vessel, which had been tested the day before. Because of the difficulty of charging these batteries, it had been decided to leave them connected to an electrical outlet overnight.

INITIATING cause was apparently the production of a dry battery system remained under charge the whole night.

Contributing or root cause may be related to the prototype character of the boat, which had been put in operation without the due safe testing phase.

inflatable boat, battery system

The boat was one of three prototype boats, already operating in harbour.
The evening before, it had been decided to keep the battery system of the boat plugged to the grid, because of a difficult charging process.

The boat is completely destroyed.

It is well known that certain type of batteries can emit hydrogen under operative and/or anomalous conditions.
The fact that the battery system of the boat was reported 'difficult to load' may indicate a battery malfunctioning, or a wrong charging operation. In any case, the fact that the boat was one of three prototype seems to indicate that the testing phase BEFORE starting service in the harbour had not been adequate to identify all the risks.