Lifeboats on passenger ships are usually designed to be swung clear of the vessel on davits, then lowered by cables to water level.

However, if the ship is listing, the lifeboats on the high side can rapidly become unusable.

If the davits are designed to reach further out than the current versions, as the ship lists further, the suspended lifeboat will pivot until its keel contacts the hull.

The hoisting tackle is then detached, and rollers with rubber tyres then allow the boat to move (sideways, as far as it is concerned) all the way into a horizontal position, and then slowly (braked by the crew on board) move in a controlled way down the side of the hull to the water.

The final few metres will most likely be fairly abrupt as the boat rolls down into the water - at this point, all hatches should be secured and sealed, and all personnel on board need to be wearing seatbelts.
-- 8th of 7, Apr 15 2018

I thought you were going to suggest a cylindrical lifeboat that rolls down the side of the listing hull.
-- DIYMatt, Apr 15 2018


How about inflatable slides that the lifeboats slide down. The slides could be clearly marked "this is not a flotation device" yet be engineered to be adequate flotation devices anyway.
-- beanangel, Apr 16 2018



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