You seem to be trying to make a point while ignoring the fact that your point has been explicitly addressed by the article you are attempting to discus (apparently without having read it).
FTA:
> Past work has suggested that battery electrification of marine vessels is unfavourable given the low energy density of batteries relative to hydrocarbon fuels28,29,30,31. However, their assumptions about battery energy density and cost are outdated, differing in some cases by one to two orders of magnitude from today’s best-available figures of 210 Wh kg−1 specific energy32 and US$100–134 kWh−1 (ref. 33). Furthermore, these studies assumed that the maximum battery capacity is limited by the existing onboard space dedicated to mechanical propulsion systems and fuel storage, so their findings suggest that battery-electric ships would require several recharges to traverse even short routes.
> For example, for a 5,000 km range small neo-Panamax ship, we estimate that a 5 GWh battery with lithium iron phosphate (LFP) chemistry, with a specific energy of 260 Wh kg−1 (ref. 34), will weigh 20,000 t and increase the draught by 1 m—a small fraction of the ship’s total height and well within the bounds of the vessel’s Scantling (maximum) draught. For voyages longer than 5,000 km, the increase in draught exceeds the vessel’s Scantling draught.
> We find that minimal carrying capacity must be repurposed to house the battery system for most ship size classes and along short to medium-length routes. For a small neo-Panamax containership, representing an average containership in the global fleet, the volume required by the battery system is less than the volume currently dedicated to the ICE and fuel tanks for routes under 3,000 km. For the longest modelled route of 20,000 km for this ship class, the battery would occupy 2,500 twenty-foot equivalent unit (TEU) slots or 32% of the ship’s carrying capacity. Supplementary Table 1 provides the baseline values used for each ship class.
> In the baseline scenario, the TCP of a battery-electric ship is lower than that of the incumbent ICE vessel only for ship classes larger than 8,000 TEUs over voyages of less than 1,000 km (refs. 5,40,47,49,50). Over longer voyages, the additional cost of the battery system, increased power requirements and charging infrastructure outweighs the savings from fuel switching and the efficiency gains of direct electrification. However, if the environmental costs of NOx, SO2 and CO2 are considered, the cost-effective range increases to 5,000 km across all size classes given the high emissions rates of HFO relative to the emissions intensity of the US grid.