Fuel burn might be an issue.
I used to run my 250 Mako cuddy with twin 150 (1988) Johnsons to Bimini from Boca regularly for 10 years.
Always took 42 to 48 gals. in about 2.5 hrs for about 65 miles.
Once we had a bad chop, nothing big, that slowed me down to where it took 5hrs and 83 gals. On &...