Some of these could burn 500 gallons of diesel an hour at full speed.
Hasbeen,
Yeah well, that's because of two bad reasons;
1; you wanted to make as much money as you could
2; because you were pandering to impatient hordes who had no appreciation for the reef anyway. Much of the diesel most likely went into the air conditioning units for the pale Southerners who also poured gallons of Sunscreen lotion onto themselves & which subsequently poisoned the coral !
Then, you blamed the farmers for it !

What a miserable rant individual, I'm surprised at you.

We ran high speed boats because the trip to the outer reef required high speed. We had 8 hours to take people out to the reef, show them what was there, & bring them back. A traditional launch, traveling at 10 knots took about 4 hours to get there, & 4 hours to get back giving exactly zero time to show people the reef. The fast boats gave 3 hours for diving, snorkeling & coral viewing on the reef.

Horses for courses, we also had traditional launches for different jobs, such as extended reef charter fishing trips. My favorite was a 45Ft launch, catering to 8 guests, up to 10 at a squeeze. She did only 8 knots, but did so burning only 5 liters an hour, thus could stay out there for up to 10 days.

Occasionally I could get away with skippering one of these myself. You were on duty 24/7 on these trips, but it was wonderful relaxation after weeks of 7 AM to 7 Pm in the office, or surrounded with tourists on the large boats.