Have seen converters with those same specs being used in CPAC machines and their distributor recommends a 150W inverter with a 12V plug for portability. I would think that if the actual power draw of these units were closer to the converter output specs that a 200W inverter might be more appropriate. Nevertheless I do not know what type of machine it is and what its actual power draw might be, but if it were me I would consider a 400W inverter with dual receptacles. Price wise they might be about $15 more and they are at the threshold where you may still use a 12V plug. This unit would have the advantage of having the capacity for powering other electronics while running your machine. It is recommended that any inverter larger than 400W be hardwired to the batteries and safety fused. Since it is likely that you will be drawing on the batteries while the boat's engine is off it would be nice to find out from the manufacturer what the actual draw of the unit in Amps is at 120V. There might be a label in the machine which provides this information. What I'm leading to is being able to calculate for how long you could run the machine before there is a need to recharge the battery(s). An electrical piece of equipment that draws 1 amp at 120V will draw 10 amps at 12V and with an inverter's inefficiency factor the total draw would be around 11.5 Amps. A single 12V battery may have a safe usable capacity of 50 to 55 Amp/hours so if ran continuously the battery would require recharging after around 4 1/2 hours. Digging deeper into the battery or having additional batteries will extend that time. Also having on board means of recharging like solar panels or generator will extend the time. If the machine only needs to run for short intervals then the amp/hour consumption goes down and the need for recharge during use may not be an issue. Also be aware that in an emergency you could combine two 12V batteries in "series" to power the 24V unit directly without the use of an inverter or the converter, just a clip on cable adapter.
