On Thu, 03 Jun 2004 15:03:10 GMT, "John Smith"
wrote:
Gould,
Since you boat with a trawler I think you have forgotten what happens when a
planning hull is no longer planning but is "muscling" it's way through the
water. Most boats drop off of planning at 2200 rpm to 2800 rpm.
The numbers do look reasonable for a "planning hull".


"Gould 0738" wrote in message
...
Mileage at 1500 rpm (6mph): approximately 6.2mpg
Mileage at 2500 rpm(9mph): approximately 3.5 mpg
Mileage at 3000 rpm(25mph): approximately 6.5mpg

==================================================

The numbers are reasonable for a planing hull, problem is that they
didn't test at lower than 1500 RPM. At 1500 the boat is already
exceeding its hull speed by a considerable margin and leaving a big
wake. If they had tested at 1000 RPM the results would have been as
expected and shown the best fuel economy. No one wants to travel at
that speed with a planing hull of course, but that is where the best
economy is.

"Wayne.B" wrote in message
...
On Thu, 03 Jun 2004 15:03:10 GMT, "John Smith"
wrote:
Gould,
Since you boat with a trawler I think you have forgotten what happens
when a
planning hull is no longer planning but is "muscling" it's way through
the
water. Most boats drop off of planning at 2200 rpm to 2800 rpm.
The numbers do look reasonable for a "planning hull".


"Gould 0738" wrote in message
...
Mileage at 1500 rpm (6mph): approximately 6.2mpg
Mileage at 2500 rpm(9mph): approximately 3.5 mpg
Mileage at 3000 rpm(25mph): approximately 6.5mpg

==================================================

The numbers are reasonable for a planing hull, problem is that they
didn't test at lower than 1500 RPM. At 1500 the boat is already
exceeding its hull speed by a considerable margin and leaving a big
wake. If they had tested at 1000 RPM the results would have been as
expected and shown the best fuel economy. No one wants to travel at
that speed with a planing hull of course, but that is where the best
economy is.


Exactly!