Im In :) Again!

Hi- first and Last days are the best...

Just finished the wire/paperwork on a 1987 43 Californian Aft Cabin Cockpit Motor yacht. Really clean boat very well maintained.

Boat performed well on sea trail with 3208 motors. Question is were is the sweet spot on fuel?

First run will be to bring her home from Marina Del Ray to Ventura so about 50kn miles.

WOT 2800RPM boat runs at about 21kts, at 1800 she runs at about 11kts at 1500RPM she holds at 9kts...

Any thoughts Im thinking keep her at about 10kts or ?

Thanks- Photos to come!

Welcome aboard. Sweet spot will be slow speed. On plane it should be cleanly on plane whatever that speed is.

Welcome to TF, and we look forward to hearing - and seeing - more...

Most boats actually have at least two "sweet spots" . One on plane and one at displacement speed.

Once you get a little more familiar with the boat you will be able to detect the sweet spot without even looking at your instruments . The boat feels smooth, the engines purr nicely, vibration is minimal.

It isn't cast in stone or rocket science, you will know it when you are there.

pete

Welcome to the forum. Best of luck with the new boat.


Greg.

justaddwater said:

Question is were is the sweet spot on fuel?

Click to expand...

The sweet spot on fuel is a calculation of fuel burnt over distance. Your sample provides a limited window with only RPM and speed.

Anything above theoretical hull speed and fuel consumption for takes a dive until you get up on plane.

The sweet spot is whenever your partner doesn't have a death grip on the railing screaming "We're going to die"

Here's a link to a chart that will give you the hull speed. You will need to know the length of the boat at the water line. The rest comes from this formula below:

velocity in knots = 1.35 x the square root of the waterline length in feet.

https://www.frontrower.com/hull-speed-chart.html