Expedition Expedition Navigation Software

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7/27/2017 9:29 am  #1

Expedition - First Time on a race

Hi All - 

I just completed the Port Huron / Mackinaw race in Michigan. This was the first time we used Expedition underway in a race. A couple of things came up that I wanted to share and get some feedback from experienced users

- The boat could not provide continuous power to the laptop for the duration of the race - so we frequently ran on batteries until I could convince the skipper to turn the engine on to power the PC. That would have been fine, but I had installed a local wifi network to feed data to ipads using Ventus. Without power, naturally, this didn't work. Do most expedition users count on continuous power or was this an unreasonable expectation ?

- I spent two weeks downloading three weather models a day and ran course and route optimizations - this worked well. Unfortunately on race day, all three of the predictions were entirely wrong. Predicted winds out of the Southeast, actual winds out of Northeast. Predicted winds 10-15, actual 20-25. I used expeditions scaling and wind direction corrections, but at this point I was sort of at loss as to whether this scaling was going to generate good routing info because the difference between predicted and actual weather.

- While underway we noticed the boat was sailing below it's polars. When we checked boat speed to GPS SOG - it was off by 1.5 knots (We are sailing in Lake Huron which has no tides and minimal currents). We concluded the instruments were underreporting speed.

- The skipper was under the impression that expedition was basically going to tell him when to tack/gybe and the direction to steer the boat to get the fastest possible course. That was not my experience. I believe that expedition is a powerful tool for planning and communication during a race but that a boat's tactician is a much better person to make those calls with input from all various data sources including expedition. I don't have enough experience to prove my case on this - any thoughts from more experienced users.

- We were unable to get weather data underway - even though I had setup and tested extensively a sat. phone and Xgate. So, with bad weather data at the start and then no way to update I wasn't quite sure how to use the software in these circumstances.

- I intended to use expedition during this race to start capturing performance data on the boat with different wind speeds and sail configurations. The skipper needed me mostly to be on deck, so I lost that opportunity. Based on my experience using expedition underway is almost a full time job - but since I needed to be on deck I had split my time. What's been your experience ? Do you generally sit at the nav table and monitor expedition during the race - In general what are the expectations of the skipper on your boat.

Really appreciate any replies - I'm a huge fan of expedition but am struggling to find a way to integrate it into the boat's operation at this point.


7/27/2017 1:14 pm  #2

Re: Expedition - First Time on a race

I did a lot of Mac races and always found them very hard.

​In my experience, NOAA's NAM model was almost always the best source of data.

What is the power supply? If you are using an inverter, you will chew through batteries for laptops.

​You would be surprised at the currents in Huron. The GLERL current forecasts were a good source of currents.


7/27/2017 5:25 pm  #3

Re: Expedition - First Time on a race

We were using an inverter to power the laptop  - and yes that was really drawing down the batteries. I will check GLERL currents and NOAA's NAM model.. Thanks.

     Thread Starter

7/31/2017 2:24 am  #4

Re: Expedition - First Time on a race

For your notebook you should use a 12V car adapter instead of an inverter.  This avoids the losses of an inverter.   As for the wifi network I use Connectify Hotspot installed on the PC where Exp runs.  Works very reliable and make an additional wifi router redundant (and likely safes a little in power consumtion as well).

Regarding your weather forecasts to be off from reality:  were they completely off at all or were they fine except for a time offset?    In the later case it can help to have a barometric sensor connected so you can verify to what extend the predicted pressure is offset and therefore the wind forecast is offset.  You can then instruct Exp to take this offset into account when doing the optimal routing.

The Exp stripcharts make an excellent source of info for instrument calibration.  Comparing BSP to SOG (on non tidal water without currents) over time might help.  Also take heel into account in case your instruments are able to correct BSP for heel (or do this correction in Exp).

Analysing the performance data is best done from an armchair once you are back home.  Take the PC with you, load the track in Exp,  the logfile in stripchart and enjoy!



7/31/2017 4:11 am  #5

Re: Expedition - First Time on a race

Thanks ZeeZee - will try Connectify Hotspot. The weather forecasts were completely off. I had three predictions (NOAA, SailDocs, PredictWind) predict wind from the SE for 2 days at 10-15 then building 15-25. The actual was NE moving to E and building from 15 to 30-35. Am waiting to get the laptop back - will try and figure out if the forecast was delayed ...


     Thread Starter

7/31/2017 6:44 am  #6

Re: Expedition - First Time on a race

In case of a time shift in the forecast you can enter this in the Optimal routing advanced settings.   A negative number of e.g.  -180 minutes means that e.g. the forecast from 5pm happens already at 2pm.  A positive 180 minutes means the 2pm forecast only happens at 5pm (so a delay).
A nice future enhancement for Exp would be to reflect this entered time shift also when drawing the wind barbs on the map, but currently this is not the case and it is only used for optimal routing.


7/06/2018 10:47 pm  #7

Re: Expedition - First Time on a race

Nick wrote:

​You would be surprised at the currents in Huron. The GLERL current forecasts were a good source of currents.

Hey Nick,

Bumping this dead thread for insight on GLERL. Are you familiar with any format of this data that can be imported to Expedition?


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