This alternative experience is provided to accommodate guests with conditions preventing them from boarding the subs.

The emphasis, the British pilots' union said, "must be on preventing potential terrorists from boarding aircraft."

They appear to be friendly, but they are obviously crowding the deck to show their numbers and prevent anyone from boarding her.

The reporters were swarming over the dock, prevented from boarding the yacht by the police.

However, at the dock, Rochefort sets up a blockade to prevent anybody from boarding the ships.

But the rough seas, high winds and thick oil around the tanker prevented them from boarding her.

The authorities prevented the Africans from boarding the trains so as to question those involved in the brawl.

The crew prevented the pirates from boarding by firing high pressure water cannons at them.

According to Greenpeace, the crew of the rig tried to prevent them from boarding with water cannons.

This design also prevented the outsiders from boarding the ship and aiming at the personnel inside.