Reply
 
Thread Tools Search this Thread
 
Old 09 March 2007, 19:46   #1
Member
 
Country: Other
Town: Stanley, Falkland Is
Boat name: Seawolf
Make: Osprey Vipermax 5.8
Length: 5m +
Engine: Etec 150
Join Date: Mar 2006
Posts: 3,726
Fuel consumption

I've just measured the fuel consumption of my engine (Johnson 2 stroke carb, 115 V4) for the first time.

58.6 litres to cover a GPS measured trip of 45.2nm seems a bit on the high side to me, anybody else with similar old-tech carb motor of a similar size able to comment?

I thought the rule of thumb was about 1ltr per nm, I know carb 2 strokes are thirsty but 30% more thirsty? This was not flogging it in fact a fair bit of time was spent at about 10 knots looking at a nice bit of coastline I'd not seen before, average speed on the whole journey was 15.something knots.

Didn't see any whales either (which was the object of the trip)
__________________
A Boat is a hole in the water, surrounded by fibreglass, into which you throw money...

Sent from my Computer, using a keyboard and mouse
BogMonster is offline   Reply With Quote
Old 09 March 2007, 20:07   #2
Member
 
Pete7's Avatar
 
Country: UK - England
Town: Gosport
Boat name: April Lass
Make: Moody 31
Length: 9m +
Join Date: Aug 2001
Posts: 4,951
Probably about right, but 10 knots will be your problem, boat isn't planning but running bow up using a lot of fuel but mot much speed.

You could try this:

http://cgi.ebay.co.uk/Navman-F41-mar...QQcmdZViewItem

Pete
__________________
.
Ribnet is best viewed on a computer of some sort
Pete7 is offline   Reply With Quote
Old 10 March 2007, 12:56   #3
Member
 
Country: Other
Town: Stanley, Falkland Is
Boat name: Seawolf
Make: Osprey Vipermax 5.8
Length: 5m +
Engine: Etec 150
Join Date: Mar 2006
Posts: 3,726
Cool...

Ebay won't let me register from here as they now require a credit card to authorise new users and they don't like my address (!) how much does one of those cost new?

Could be right I suppose, 8-10 knots is probably not a "best fuel economy speed" - though we probably only did about 10 miles like that (between looking for whale spouts, and looking at coastline).

I will keep a log of fuel and distance for a few tankfuls and see what the long term average is I think.

Just out of interest I suppose the best fuel economy speed is "just on the plane" is it? My feeling after a year of using but not measuring is that about 18 knots is probably the most economical cruise, fairly low revs but still well up on the plane.
__________________
A Boat is a hole in the water, surrounded by fibreglass, into which you throw money...

Sent from my Computer, using a keyboard and mouse
BogMonster is offline   Reply With Quote
Old 10 March 2007, 13:23   #4
Member
 
Pete7's Avatar
 
Country: UK - England
Town: Gosport
Boat name: April Lass
Make: Moody 31
Length: 9m +
Join Date: Aug 2001
Posts: 4,951
With the vodka and tonnic about £160 over hear. I think if you start plotting the fuel figures then the graph will be pretty much flat for the mpg. Have a look at some of the US boat test sites, mpg figures only seem to vary at slow and flak speeds. In between its almost flat.

Pete
__________________
.
Ribnet is best viewed on a computer of some sort
Pete7 is offline   Reply With Quote
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off




All times are GMT. The time now is 06:40.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2024, vBulletin Solutions, Inc.