A domestic type pressure jet boiler might well be suited to a wide beam, but there are drawbacks to their use on smaller systems. Bubble did make a small PJ boiler, but with a small load it came up to temperature very quickly and cut off, shortly after it would restart as cooler water came back, but the ones I commissioned never really brought the boat up to temperature, as the pre purge and post purge operations circulated cold water.
There are also problems with small pressure jet boilers running on diesel, requiring a high pressure through the nozzle, and a preheater in the nozzle supply, otherwise you get poor/non ignition and very dirty electrodes and nozzles. The higher combustion temperatures require good design in the flue system to stop the blast tube disintegrating.