Wotta Messsssssss
The "foaming diesel fill" demon is everywhere! Just last week I was crewing with a friend on his 35 foot double ender and we needed to fill up after a two day coastal delivery. (No wind, all motoring.)
The nozzle at the Astoria marina was evidently set up for a fast flow for fish boats and big yachts, and the first attempt shot about a cup of diesel all over the cockpit seat where this design has it's fill pipe.
After some muttering the skipper got the hang of a very soft squeeze on the nozzle and even then had to do kind of a long series of small squeezes to get the fuel in without its foaming over. About 35 gallons was needed, and it took some long minutes to git-r-done.
FYIW dept: On our own boat, I rerouted the vent line as part of the tank replacement project and removed quite a bit of horizontal vent hose. This seemed to help.
Still, I sometimes have to be really careful with that initial fill startup. Also, any dock that mostly caters to big boats will have the larger nozzle size and.... there you go again...