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Information displayed on my chartplotter
On the last leg I was struck by how interesting some of the information on my chartplotter was and so I thought I would show you a little more of what information I have at my disposal when at sea.
Firstly here is a pic of the chartplotter when I was on the west side of Jura/Lunga yesterday…
Apart from the chart information there are 3 distinct areas of information… top left, top right and finally all the info at the bottom.
Top left
There are two numbers…
- the top number is the GPS speed. Currently showing 18.4kts. I do not have a log and so this is my only way to determine speed and it always shows speed over ground (SOG).
- the bottom number is the battery voltage. Currently showing 14.9v. I use that mainly in port to determine the state of my battery charge but it is useful at sea to determine if the alternator is working.
Top Right
This is the depth from my sonar sensor which is mounted on the transom. Currently showing 143m! The Lowrance LMS-332 is also a fishfinder and so it is useful to determine bottom composition which can give a hint to how good anchor holding might be. It is useful for finding fish too!
Bottom
This is probably where my system differs from most chartplotters. My Suzuki DF115 engine has a NMEA2000 data link to the chartplotter and it can display many engine related data and it is from the engine that the data items on the bottom are sourced. All of this data is fuel related. I will run through each item in turn and explain how I use them when at sea. Hopefully you will see how useful this info is to me on this event.
There are 5 data items… two bottom left, two bottom right and one bottom middle.
Bottom Left
- The top number is the fuel flow at that exact moment in litres per hour. Currently showing 18.6 ltrs/hour.
- The bottom number is fuel used since the last reset. Currently showing 28.18 ltrs. I always reset the fuel stats prior to leaving port so this shows fuel used on this leg.
Bottom Middle
This number is calculated by the system. Currently showing 71.78 ltrs. Prior to leaving port I enter into the system the number of litres of fuel on board. The system knows how much fuel has been used (from bottom left) and it simply subtracts that and displays here fuel remaining. I use this as a cross-check against the normal fuel gauge to double check the current fuel remaining.
Bottom Right
This is the section that I find most useful when at sea…
- The top number shows the fuel usage in miles per litre. Currently showing 0.98 nm/ltr. It calculates that from the fuel currently used (from bottom left) and the speed over ground (from top left). It really shows me how efficient the engine is at that moment. Typical readings here are 1.0 when planing in smooth water down to 0.6 when running in rougher water. It can read 0.3 just before getting onto the plane and I did see 5.0 yesterday when on tickover but still doing 7kts downtide! I aim to keep this number between 0.7 and 1.0 and that means that I will be using fuel between the best and worse case scenarios that I have planned for.
- The bottom number shows my range in miles at the current rate of use and with the current fuel remaining. Currently showing 70.3 nm. This is a great number. It shows me how far I can go given the current usage of fuel… which means current conditions, current engine rpm, current speed etc. Basically, it tells me that if nothing changes then that is how far I will go before I run out of fuel completely. Obviously I do not plan on running out of fuel and I always want this number to be well above the distance to my destination. How do I know my distance to my destination? Well that is on my navigation screen and I will explain that in another blog entry later in the trip.
Summary
Having this amount of fuel usage and range information at a glance is an absolute must for me when going on extended trips. Many RNLI callouts are a result of vessels running out of fuel and to ensure that you don’t run out you need proper planning before leaving port, up to date and accurate information when at sea that is constantly monitored and used properly so that if it looks like there may be a fuel problem then some action can be taken to ensure that you don’t actually run out - such as slow down which can often save fuel or even divert to a closer port.
I hope you have found this post interesting. Please comment and let me know.
When I get the chance I will do a blog on the navigation page on the plotter.
