It might be worth finding more detail, preferably externally verified, than a vague "up to 30%" claim before judging it as a no-brainer.
Also from what I know of the shipping industry I would only expect it to be seen on new ships as the cost of retro-fitting would be high even without considering the opportunity cost of the ship needing to be in dry-dock for the operation (and needing to get to and from the dock, if there is not one where the work can be done along its owner's normal routes).
And given ships change hands surprisingly often, how long it takes to hit break even (i.e when the cost of the fuel saved, less any extra maintenance costs the tech may be subject to in that time, equals extra initial outlay) will have a massive effect on whether it is worth it to the initial owner of a new ship.
And a new ship is a huge capital expenditure, with a long lead time from plan to implementation. If the tech is relatively new it may not have existed at all when ships currently rolling into service were conceived, and with that level of capital involved designers are going to be pretty conservative about the risk of trying relatively new tech, so maybe it will become common but at a much later time.
Also from what I know of the shipping industry I would only expect it to be seen on new ships as the cost of retro-fitting would be high even without considering the opportunity cost of the ship needing to be in dry-dock for the operation (and needing to get to and from the dock, if there is not one where the work can be done along its owner's normal routes).
And given ships change hands surprisingly often, how long it takes to hit break even (i.e when the cost of the fuel saved, less any extra maintenance costs the tech may be subject to in that time, equals extra initial outlay) will have a massive effect on whether it is worth it to the initial owner of a new ship.
And a new ship is a huge capital expenditure, with a long lead time from plan to implementation. If the tech is relatively new it may not have existed at all when ships currently rolling into service were conceived, and with that level of capital involved designers are going to be pretty conservative about the risk of trying relatively new tech, so maybe it will become common but at a much later time.