In a 1 - 2 hours max. maneuvering I will shut the fuel pump's supply and open for 1 - 3 strokes, every 10 mins if M/E is running on HFO or every 2-3 minutes on MDO / LSMGO depending on M/E rpm and fuel lubricity additive (for LSMGO). For longer maneuvering (Suez, Panama, Magellan Str., Danish Str., ...

I am not familiar with your boiler, but it looks like while your tube is emptied, some steam is leaking into the tube (the steam inlet valve is not holding). The heavy hammering occurs while the steam is condensing into the tube. Another reason that may be independent or together with the condensing...

In European or selected U.S. ports you have to run the boiler on LSMGO or MDO with atomizing steam. I have done the same with Mitsubishi and Volcano burners without any issue. The atomizing air is used when the atomizing steam is out of order / pressure range (cold starting or steam pressure loss).

It depends on what risks are you ready to assume and what kind of maneuvering you are performing. You know that an explosion in the starting air line is one of the worst nightmares in E/R. I assumed myself the risk to allow several kicks on an arrival maneuvering in a terminal that banned one sister...