Japan's transport ministry has compiled new safety measures for sightseeing boats to prevent a recurrence of the fatal accident that happened off the coast of Hokkaido in April.

The ministry's expert panel approved the new draft measures on Thursday.

The tour boat "KAZU I" with 26 people on board sank off Shiretoko Peninsula, northeastern Hokkaido. Twenty people have been confirmed dead and six others remain unaccounted for.

The draft safety measures are comprised of 66 items. They include the introduction of an examination system for operation managers, as well as education and training for crew members.

The measures say mobile phones will no longer be an acceptable form of communication equipment, as they tend to be unreliable depending on the location.

Operators will be obliged to equip their vessels with life rafts.

Penalties for violators will be harsher than before.

The new measures will also require crew to check hatch covers before departure. The government's Transport Safety Board had concluded that the "KAZU I" sank because the latch of the hatch cover on the forward deck had worn away, allowing seawater to enter.

Methods for hatch inspections by the Japan Craft Inspection Organization will also be changed as it was pointed out that their inspections were insufficient.

The draft also includes a timeline for implementation of the measures. By fiscal 2024, the ministry aims to make it mandatory for vessels to be equipped with life rafts. The establishment of the examination system for operation managers is scheduled for around fiscal 2025.

The transport ministry says it plans to set up another panel to study whether to make it mandatory for bulkheads to be watertight. The Transport Safety Board had earlier said that if there were no holes in the bulkheads of "KAZU I," the sinking could have been prevented.

The ministry says it will make a decision on the possible mandate by the end of March.