Fuel usage tips

[fishfeeder]

I Have a Vagabond 6.2, with a 200hp Evinrude (2004 Ficht) and 200L tank and I am looking into getting Trim Tabs to help level the ride as I think this will help in keeping the boat running in a better rev range hence better fuel figures.
At the moment off shore I mainly drive to the conditions and try to sit on the plan as much as possible with minimal amounts of throttle changes but ofcourse when it gets bumpy I really need to be on and off the revs to keep planing and so the crew arn't thrown around to much.

I just bought the fuel sensor to hook up to my HDS unit to help keep track of fuel.
I am not sure of my usage at the moment but having a guess its around the 1km per L which to me sounds like a lot.

Just wondering what other people do to get better Km per tank of fuel as I am hoping to goto the next M&G up at 1770 and fuel is my biggest problem and on this site there are a lot of people who do crazy KM in search of fish just wondering what are there secrets ??

Fishfeeder

[D river]

I have a 5.2m glass boat with a 130hp yammy 2stroke. I get about 1k/800ml but always allow 1k/1L. I've found no difference in my fuel consumption in the chop to the glass out all that seems to change is the speed and comfort. My average trip consists of 216km and on average I use 165L. This has been the case several times in all conditions and if its flat so am I. I also bought a fuel sensor but the thing is never right so I just hooked up a 20L tank and ran it dry n worked out the K's per L from that and its been spot on each time. My boat does 80kph flat out but I like to sit on 60-65 just so the motor not being rev too hard. That and 80 is to fast in a 5.2m boat.

[Chimo]

Hi Fishfeeder

I have a vag with 2 by115HPs

Fit a set of tabs, I have Lencos, and you will find an improvement and get rid of shoulder thud by having the hull working better due to it being level

I also have a set of foils on each motor and they too have helped to get the hull up and planing at slower speeds. At high cruise and above the foils are clear of the water as the motors are trimmed up / back and this is assisted by the tabs even when they are fully up. The plates do add to hull length and when up they are about 5 mm above the bottom so no drag.

The Lencos were installed by Lindsay Fry at the original Seafarer and they are what he recommended, simple to instal as no hydraulics.

Just do it!

Cheers
Chimo

[Tinshack]

Hi Fishfeeder, this is what I did. My boat is a lot smaller than yours, its a Southwind SF17/SF565 glass boat with 115hp V4 2 stroke yammy, total weight on the water is approx. 1200kg's with 200L of fuel. I have played around a bit & done a lot of reading what others have done. Bought a fuel sensor pluged it into the NEMA Lowrance network & was originally getting 0.8 - 1 km/L. First thing I did was put on a permatrim foil. This made a huge difference in raising the rear of the boat & keeping the boat level especially in a head on swell & also stoped the up & down bow action when in choppy conditions. This made minimal change to economy but huge difference in comfort at speed. Solas was the pick with prop trials, they were happy to keep exchanging props until I got what I wanted. I tried 3 blade, 4 balde & ended up with 3 blade new saturn with lower pitch than what I originally had but larger blade, so less slip when offshore. Lost a bit of top end speed (3-4km/hr) but gained WOT rpm's, higher rpm's at cruise speed but lower load on motor. Went from 1.2km/L up to 1.6km/L average on trip. Next thing was to raise the motor 2 holes as trial & what a difference! When glass conditions I can get over 2km/L average at 55km/hr. I now average 1.5km/L for 240km trip. I found if I can get the boat level I can sit on a higher speed with comfort & get more of the boat out of the water hence better fuel economy. I think I have done the best I can with a 2 stroke but very happy with 1.4km/L @ 40km/hr if rough & 2km/L @ 55km/hr if glass calm. Getting your boat level with water & not transom heavy requires less energy to push it through the water, also raising the motor reduces the drag effect & hence increases speed & improves economy. Changing props & raising motor is a bit of a pain but cheaper than upgrading outboard. Others can comment on the effect on economy by installing trim tabs as I am not sure what drag effect they put on your boat. Cheers.

[trueblue]

I dropped my cruise back from 4600 rpm to 3900 - 4100 rpm and in combination with keeping a steady throttle dropped my fuel usage by nearly 20% (yammy 130 2 stroke)

[Jabba_]

Trime tabs will help a bit, but to get the best results, ensure your motor is rigged correctly.. What that means is, your motor is propped to reach 5600rpm, and your engine hieght is set so your cav plate is above the water while cruising..
(check out this site) http://www.veradoclub.com/smf/index.php?topic=137.0

Another thing to remember is your prop.. I owned a 2002 250 Ficth with a 22" raker, was getting 1.2km/lt... Then I upgraded to a 2007 250 E-tec with a 21" Viper getting 1.5km/lt, now I have a 20" Rebel and easerly get 1.6km and with a some fine adjustments to the trim I can achieve 1.75km.... I still have my old 22" raker and with that prop on my E-tec, I at best get 1.4km...

A 17" Rebel I would think would make a big improvment to your economy...

[Chimo]

Just read the later posts. Agree with all and I did forget to mention that like all the others my motor has been lifted too! (foils etc are above the surface at speed)

C
C

[fishfeeder]

Thanks guys, This is all good info and I think my motor hight is fine compaired to the link Jabba posted, and the cav plate it just above the water, I will check my prop on the weekend and post the size, at a guess it was something like a 20, 14 3/4.... It reves to 5500 (about 78-80km) but takes a bit to get from 5000-5500 if there is much of a head wind or current

The plan at the moment is to get the Trim Tabs installed, Then work on the prop.
I also realise I might need a better driving style offshore to get the best figures and the trim tabs will produce drag in the water when down, but I am hoping that keeping the boat more level and then in return make it easier to keep a better throttle control and rev range....

Cheers

[Chimo]

You wont need the tabs down much (if you go Lencos or Bennetts )so little drag.

I probably twice the weight on my Vags bum with two motors at about 165 kg each plus oil bottles and 4 batteries and my tabs are only tabbed down less than a second for good affect.

Cheers
Chimo

[timddo]

Hi Fishfeeder, this is what I did. My boat is a lot smaller than yours, its a Southwind SF17/SF565 glass boat with 115hp V4 2 stroke yammy, total weight on the water is approx. 1200kg's with 200L of fuel. I have played around a bit & done a lot of reading what others have done. Bought a fuel sensor pluged it into the NEMA Lowrance network & was originally getting 0.8 - 1 km/L. First thing I did was put on a permatrim foil. This made a huge difference in raising the rear of the boat & keeping the boat level especially in a head on swell & also stoped the up & down bow action when in choppy conditions. This made minimal change to economy but huge difference in comfort at speed. Solas was the pick with prop trials, they were happy to keep exchanging props until I got what I wanted. I tried 3 blade, 4 balde & ended up with 3 blade new saturn with lower pitch than what I originally had but larger blade, so less slip when offshore. Lost a bit of top end speed (3-4km/hr) but gained WOT rpm's, higher rpm's at cruise speed but lower load on motor. Went from 1.2km/L up to 1.6km/L average on trip. Next thing was to raise the motor 2 holes as trial & what a difference! When glass conditions I can get over 2km/L average at 55km/hr. I now average 1.5km/L for 240km trip. I found if I can get the boat level I can sit on a higher speed with comfort & get more of the boat out of the water hence better fuel economy. I think I have done the best I can with a 2 stroke but very happy with 1.4km/L @ 40km/hr if rough & 2km/L @ 55km/hr if glass calm. Getting your boat level with water & not transom heavy requires less energy to push it through the water, also raising the motor reduces the drag effect & hence increases speed & improves economy. Changing props & raising motor is a bit of a pain but cheaper than upgrading outboard. Others can comment on the effect on economy by installing trim tabs as I am not sure what drag effect they put on your boat. Cheers.

Tin shack

What foils did you install.

Coz i have the same problems. bow going up and down and it's annoying.

I have 115 yamaha 2 stroke.

[wrxhoon]

The main advantage with trim tabs is the fact that you will be able to keep a higher constant speed because the boat will be level at all times .
Because of that you wont have to be on and off as much , thats what drinks the fuel .
If you have a fuel flow meter you will be able to see this .
Of course the tabs lengthen your boat as well and that helps too.

You will be surprised the difference a prop can make to your fuel consumption.

I have tried several props in my Trophy , best to worse makes 20% difference . The only way to know the best prop is to try different props, on my boat Enertia 18" pitch works best for fuel consumpion and Vensura 19" ( 4 blade) works best for holding plane offshore.

[Tinshack]

Hi Timddo, Permatrim foil, it is the one made out of high tensile 5083 grade aluminium plate. Very strong & doesn't flex like the plastic ones.

May see it in photo attached. I think I payed approx. $200 for it.

Cheers,

Tin shack

What foils did you install.

Coz i have the same problems. bow going up and down and it's annoying.

I have 115 yamaha 2 stroke.