Any Nova 42 sundeck owners? Fuel burn

[Panacea123]

I have a 2002 "Novatec" previously marketed under "Nova brand" as well as Heritage East, Present and a few others.
Mine was one of 6 made in this newer name. I guess they did not sell well when they brought the model back after the late 80's maybe real early 90's

I have seen the specs on many of the earlier models ( all low power I.E.:120-135 hp twins. Even saw one at 660 tttl hp and 17kts, hate to think of the wake and fuel he experiences.
I consider mine way over powered with twin Cumins 5.9 210 hp turbos great motors but fuel hungry.

Burns under published fuel curve @ 1650 rpm 11.5 kts max @ 2600rpm
But still burning 5+gal/hr total @ 8.25kts

What motors do you have, trans ratio and prop size, and what is your fuel burn?
Have heard of 2.5-3 nmpg
Am thinking about prop re-pitch but engine surveyor and Michigan wheel says I'm good with what I have
Concerned with lugging motors and not reaching proper combustion temps.
Looking to maximize fuel economy and range, but more concerned about getting the most hours out of motors. (850 now)

Fuel is cheaper than re-power!
Thank for input
PS: published draft is 3.8ft
Measured mine at 4.3ft, maybe hull different (I doubt they mad a major hull mod for only 6 units

 

[BeagleBoy]

Mine is a 90/91 model Nova branded 42, with the factory optioned fishing cockpit - makes it a 48. Probably not the answer you are looking for, but the following is probably good for your general comparison as we would have a very similar hull design.
Mine has 2 x Turbo CAT3208's which will push her to 17kts. Yep, bow wave is pretty special at that speed - look out kayaks and dinghy's........fuel burn is 100ltrs an hour at that speed. I almost never drive her like that though!
At 10knots she will burn 3 ltrs a mile (30ltrs or 7.8gal an hour). I drive her 90% of the time at 8.5kts for a burn of 2.2ltrs a mile (18.7ltrs or 4.9gal an hour). She runs comfortably at this speed and I can do it for 7 days straight - 80-100NM a day. She is doing around 1400RPM for this speed.
She had 1600 hours on her when I bought her. I have put another 600 on her since. The oil usage has not changed since I bought it, and running temps are always steady at 82 degrees C (179 deg F).

 

[FF]

"But still burning 5+gal/hr total @ 8.25kts"

OF course , that is still a wake making speed.

A 42 ft boat might have a 36 ft LWL so 6 - 6.5 might get you down to 2-3 GPH

If you run many hundreds of hours a year a Flow Scan will be a big help to make a GPH/ Speed graph.

 

[S41]

Our Symbol 41 sundeck with twin Cummins 5.9 210 hp will run at 8 knots with just under 4 GPH burn rate. This is running the engines at 1400 RPMs. If I drop it down to 1100 RPM I am going about 6.8 knots with just under a 3 GPH burn rate.

This boat at idle moves at right around 5 knots. I have 4 blade 24 X 21 props on the boat.

The fuel use is the least of my expenses, so at 4 GPH, I am happy. If I run it up to 1800 RPM, I am moving at 13.5 knots and pushing a wall of water and tossing out a 4+ ft wake, not to mention drinking a ton of fuel per hour (I don't like to run her at this speed, so I don't know how much fuel is being burned).

 

[bayview]

Those engines are not fuel hungry. You must have the bow up and making wake. Slow down and see what happens.

 

[Panacea123]

Those engines are not fuel hungry. You must have the bow up and making wake. Slow down and see what happens.

I mean fuel hungry compared to Lyman's or Perkins in the 135 hp range
And slowing to 1400 rpm @ 7.2 knots is same mileage