Re: The correct prop
It works for me. You need to copy and paste it in your browser. Its kind of silly if its true. At what he says is the hull speed, it'll never get on plane. I dont think his formula is accurate. It doesn't account for weight of the boat. ie a center console boat w/ the same water line lenght will not be the same as a cabin cruiser.
I said it was interesting not necessarily accurate, but here it is...
tabhauser
No Canada
8 / 2006
post # 2 of 5
-- Interact -- View Profile Ignore User Posts In This ThreadWhisperPost Options Edit Post PM User Report Post
Back to top
Post Subject: New (used) Carver gas consumption question Posted: 18:48:15 31 Aug 2006
I picked up a 1994 Carver Aft Cabin with 454's.
I have no idea what my best fuel consumption is verse RPM.
Can someone give me an idea on this.
Thanks
tabh@hascorelays.com
www.tabhauser.com
ffraboni
greensboro,nc
9 / 2006
post # 3 of 3
-- Interact -- View Profile Ignore User Posts In This ThreadWhisperPost Options Edit Post PM User Report Post
Back to top
Post Subject: Re: New (used) Carver gas consumption question Posted: 01:54:33 5 Sept 2006
The manual suggests running at 75% of WOT... On mine it's around 3300 rpm. Generally, you want to run as low an rpm as possible to keep it on plane to maximize your efficiency. I run 454's on 33aft cabin and 32 to 3300 does it for me. You're still gonna burn plenty of fuel
rmmpe
PA
9 / 2006
post # 3 of 29
-- Interact -- View Profile Ignore User Posts In This ThreadWhisperPost Options Edit Post PM User Report Post
Back to top
Post Subject: Re: New (used) Carver gas consumption question Posted: 15:10:01 6 Sept 2006
Referring to my post to the topic started by walleyehed:
New to forum, not new to boating.
1985 Riviera currently.
This is a bit longer than I like but should provide you with some meaningful information, if you're not already familiar with it.
Generally, if you're going for best economy (MPG), running at hull speed is best.
Hull speed (Knots):
Sq. root of waterline length (LWL) multiplied by 1.3.
Example, a 28' LOA boat having a waterline length of 25' is sq. root of 25 (5) multiplied by 1.3 = 6.5 Knots.
Knots to MPH = Knots X 1.15, in this case, 6.5 X 1.15 = 7.48 MPH.
OR:
Sq. root of LWL X 1.495 = 7.48 MPH
Other than that, running in the "Sweet-spot" (usually 3,000 to 3,400 RPM) will provide the best compromise between consumption and time.
Although you didn't mention the length or weight of your Carver, more to your point:
My 1988 34' Sea Ray Sedan with twin 454 350HP Mercruisers ran 22 Knots (25.3 MPH) at 3200 RPM burning 20 GPH, which equates to 1.1 NM/gallon (approx. 1.27 MPG).
Considering the Sea Ray has prop-pockets, which, when going ahead (it handled terribly when going astern), lends to better efficiency than a boat without them, your Carver with twin 454s will be something less that that (I'd guess 80%).
Therefore, extrapolating from known data and applying it against the unknown but assumed, I suspect your Carver could get around .9 to 1 MPG, which is really not too bad.
Hope this helps.
If you want, contact me privately.
