Can Autopilots help reduce fuel consumption?

Kieran_Breheny

Kieran_Breheny

Active Member
Joined
24 Sep 2008
Messages
59
Location
Arundel
www.navigate-us.com
Can Autopilots help reduce fuel consumption? I am interested to know if anyone has had experience of improved fuel economy by using an autopilot, e.g. the trip was shorter with the autopilot, because it held a course better than manual steering, therefore you used less fuel.
 
In wondering why my fuel consumption was a bit high recently, I checked my GPS logged tracks to see if I had drifted off course or gone further than neccesary, definatley not enough to make a difference. Certainly my autopilot doesn't seem to steer any straighter than I can. Its the throttle position that makes the biggest difference I find /forums/images/graemlins/tongue.gif
 
I agree throttle control is more significant. Does anybody make a trip computer (or provide embedded software) that allows you to compare, revs/consumption/nm. You could overlay weather conditions at the same time. I know this is getting too complex and I advocate simplicity but with fuel prices it could be a useful measure.
 
In some circumstances I could imagine that an autopilot could actually increase your fuel usage... especially in a smaller boat. There have been times when I have had the autopilot on and noticed that it fights the waves when they have been coming from some quarters instead of allowing the normal to-ing and fro-ing as the waves pass by. Often, when manually steering the short-term deviations right themselves and so no significant helm adjustment is necessary to maintain course.

I have no evidence that this affects fuel usage but it seems to me that sometimes it might... just a thought
 
In an earlier existance I worked for a company that manufactured autopilots. Yes a properly set up autopilot will use less fuel than a human operator, it is also likely over longer periods of time to keep a better track. As most modern autopilots are at least semi adaptive ie theyhave some auto adjustment capability, they are likely to be reasonably well set up at any time so yes they should give you the best fuel consuption. The fule savings may only be a few percent but at todays prices if you have a boat that uses a lot of fuel a good autopilot may pay for itself in a relatively short time. When we introduced the first adaptive auti=opilot some 30 years ago it paid for its £100000 cost in months on a super tanker.
 
Talking about autopilots, I have been thinking of fitting one (I reckon I'll get more practical use from it rather than a radar).

Any recommendations for the type suitable for my boat ?

(27' sports cruiser fitted with bravo III outdrive cruising at 20 knots.)

Tom
 
Re: Can Autopilots help redYeuce fuel consumption?

Yep, bet you were going round in circles half the time, the second you took your eyes off ihe compass. Theres no more numb existance, than being the mechanical end to a bloody computer.
 
This question ignores a couple of key facts.

The most important is the question of what type of autohelm. It is a proven fact that the latest rate gyro systems are actually able to steer a better course than a human. On tests carried out on fast multihull sailboats, they provide a 3% improvement on distance covered. This equates on a mobo to fuel saved. Not a lot, but that is in comparison to a fresh human at the helm. after an hour or so, the human attention wanders and the difference becomes more apparent.

Still would not compare with reducing from WOT to 75% /forums/images/graemlins/laugh.gif /forums/images/graemlins/laugh.gif
 
Re: Can Autopilots help redYeuce fuel consumption?

Tend not to use the compass for steering if the vis is good... use something on the horizon... landmark, cloud etc... but I know what you mean and the answer was yes... relax for 5 seconds in anything but flat water and the heading was off 30 degrees.

It was 121hrs of concentration...
 
Thanks for the input. I will look into flowscan in more detail.
Its clear that AP's help in many other ways including reducing fatigue and providing and extra set of hands if your short handed.
 
saw a TV prog recently about a container ship and keeping a correct course was mentioned that it did save fuel. They do suck up a bit more than the average yacht so it must be very importent for them.

I drove a BMW recently and it had a vacum guage to show fuel consumption and I seem to remember Red X made one back in the 60s, maybe fitting one would tell you if your running at the best revs or do they only work on cars????.
 
[ QUOTE ]
This question ignores a couple of key facts.

The most important is the question of what type of autohelm. It is a proven fact that the latest rate gyro systems are actually able to steer a better course than a human. On tests carried out on fast multihull sailboats, they provide a 3% improvement on distance covered. This equates on a mobo to fuel saved. Not a lot, but that is in comparison to a fresh human at the helm. after an hour or so, the human attention wanders and the difference becomes more apparent.

Still would not compare with reducing from WOT to 75% /forums/images/graemlins/laugh.gif /forums/images/graemlins/laugh.gif

[/ QUOTE ]

To be honest it has been known almost since Sperry introduced Metal Mike back in the 30s that a half decent autopilot will outperform a helmsman over anything more than about half an hour. I have even whiled away a boring middle watch or two proving this. There are two impacts on fuel consumption, clearly a meandering course is longer than a dead straight one, but every rudder movement creates drag, and the bigger the rudder movement the more drag. Conventional autopilots will tend to use less helm than humans and at the same time keep a reasonable course, if they are sut up perfectly of course the saving is maximised, hence the development of the aadaptive autopilot back in the late 70s. Rate gyro sensing autopilots are better because the rate gyro senses heading movement much earlier than monitoring heading sensors so can apply less rudder earlier and still be effective, hence the even shorter distance traveled and at the same time less drag from rudder movement.
 
Auto helms can save fuel and time if used properly in very busy areas like Chichester harbour and the solent.

Aim it for the most direct route for the sea and then retire inside the smoked glass for a beer or two.

Once the dinghies see a flybridge at 10 knots with no one at the helm to shout at they soon stand down /forums/images/graemlins/cool.gif
















If I added here ' this is not meant as a serious post' would you believe me /forums/images/graemlins/wink.gif



I think they use more fuel.
 
You must log in or register to reply here.

Share this page

Top