Rockit 2025 : How to review the data you collected.

Tab Two : Track

The track is made up of a series of dots or circles each representing the end point for a Sample Period/Timeslot. The segments linking dots are coloured based on the boats through the water speed relative to the polars for the boat. The colour takes into account the true wind angle, the true wind speed and water speed to colour the track. Purple is the best; generally the max value for the boat or equal to the max value for the boat.

The Track menu on the left-hand side of the panel can be used to turn data options on and off. In the image above the Waypoint within the route are being displayed, Clicking a point will bring up a summary of the data for a given point.

Waypoints have a green square symbol. The apparent wind speed and water speed are also being displayed. Labels are displayed every so many dots to avoid cluttering the screen. Waypoints may also not display if they with be overlaid by other labels. You can adjust the frequency of the labels using the Data Label Frequency number field. 1 implies the data labels will appear next to all dots; 5 implies they will appear every 5 dots. When you have checked/unchecked the checkboxes on the menu you need to press the Update Track button to make the screen reload with the changes.

The Pan Up/Down/Left/Right buttons allow you to move around the map. Zoom in/Zoom Out is the Zoom control. Reset Zoom will reset the Zoom to the original proportions.

The Live data panel provides a visual representation of the data that is either currently being recorded, where the Rockit Server is recording or the data for a specific point on the Track Panel.

This was originally designed for the Rockit Server version of the product but has been brought back into the Windows Desktop/Laptop version.  Its a very effective way of seeing the data that is flowing on you NMEA 2000 bus as this will update in real time rather than at the end of each Timeslot/Sample Period.

The sail plot panel will pull the data from Sample Periods/Timeslot for a given sail then plot the boat speed against a wind speed. The result is a scatter graph with regression lines showing the performance envelope for one or more sails.

So; in the above screen shot we are plotting the boat speed against true wind speed for two sails, A1.5 and A2. We add a linear regression line to the plot for each sail to show the point at which the sails profiles cross. So, based on the data displayed it makes sense to fly the A2 in anything above 5 knots of wind -> the Yellow A2 regression line is higher than the Green A1.5 regression line.

Toggling the check boxes on the Sail Menu allows you to amend the information displayed. You can display the information at both Boat and Recording Session level. The more data you have the more reliable the data plot is likely to be.

There are two graph panels Upwind and Downwind. You can use the TWA Controls on the control menu to narrow the wind angle that you are interested in. Clicking the arrows in the top right corner of the graph panels minimises or maximises the panel. The divider between the menu and the graph panels can be dragged left/right to resize the two half of the screen.

The Trend Data Panel is there to do exactly that, show what the current trends are. The Tab is split into two halves; The left section controls the variables displayed on the graphs. The right section displays the three time series graphs.

Select the variables you want to display and click “Update Trend Graph” to pull the data onto the graphs. You can Zoom in and Out on the graphs and save the graph as an image file that you can share.

The table below lists the variables displayed.

Rockit calculates Polars at both Session and Boat level.

1. Boat Polar data is the max value from all the sessions recorded for a boat for a given True Wind angle/speed.
2. Session Polar data is the average value to a session for a given True Wind angle/speed.

On this panel we display the Session Polars as a graph and the Session Polar with the Boat value in brackets in the Table.

Session Data Polar Data Graph

Displays plots of the boat speed through the water against true wind speed and true wind angle relative to the bow. The Wind Data is grouped into 2 knot speed bands and 5-degree angle bands. The session value plotted is the average value for the given wind speed/direction/boat speed combination for a session. The number will continue to evolve for the duration of the session. For a given wind speed/direction/boat speed combination corresponding boat values need to have been recorded i.e. if a session has winds only in the 4-6 knots true range and sails just on a beam reach 90 degrees to the wind only those segments will be populated.

Session Data Polar Table

Displays the information from the graphs in table form. This table also pulls in the calculated boat polars. This is displayed in brackets next to the current session value. The numeric values are coloured to indicate the sessions level of performance relative to the boats best speeds. So if the Polar values for the session are in the top 10% the text will be green. If its outside the top 30% the text will be one shade of blue if there is no data for the current session the 0 value and best performance in brackets will be another colour blue.

This Tab displays a rolling view of the data.

It shows the summarised data points collected for the last 10, 100, 1,000 or 10,000 sample periods when in recording mode; the number displayed is based on the value selected using the Max Records To Display drop list.

The first 23 data points (rows) are fixed and generated from the NMEA data collected by the Data Collection process. The remaining data points are extracted from the Boat Configuration settings and reflect the configuration settings at that point in time. The configuration settings are user configurable. In the example above “Actual Crew Total Weight” onwards is boat configuration data. Changes to the boat’s configuration made mid-session will be reflected on this table.

There is a column in the table for each timeslot. This is a useful guide to the raw summary data that sits behind the graphs and tables on the other Tabs. This view gives a good idea of which timeslots any erroneous NMEA data might have arrived in. For instance: if you boat suddenly starts to do 100knots through the water for a timeslot then you have probably received a corrupt piece of data from the source systems.

Current Boat Config Panel

This allows you to set the current active config items. So, for instance, if you want to reflect a change in the boats sail plan you would follow the steps below; To change from using the A1.5 to the A2.

1. Select the Active Item Flag Field for the currently active row (the A1.5), and use the drop list that appears to set it to “No”
2. Select the Active Item Flag Field for the new active row (the A2), and use the drop list that appears to set it to “Yes”

Stepping off the record so that the drop list disappears will say the changes to the Rockit database.

You can also edit the Config Item Value by double clicking in the field. Once you have made your change step off the record to save the change to the database.

This feature is useful for recording things like the current Helmsman. So the config Item Value would go from “Bill” to “John” and that would be reflected in the recorded config item data. Rockit uses this Boat Config Item data as the basis of the information it records for each Sample Timeslot. It stores a copy of the Boat Config Items state at the point in time of the Sample Period. Retrospectively editing the Boat Config Item information stored against the Sample Periods is possible as part of a bulk edit and will be covered later in this article.

You can also from here open the Boat Edit screen or export the boat current configuration to csv file.

Sail  Config Items and Performance Plots

Sails are defined as Boat Config Items. So our test J109 has a set of 7 sails defined; A1.5, A2, A5, C1, C3 etc.

The sail performance graphs are generated using this information. So boat performance will be extracted for the sample periods where a sail (e.g. A1.5) is active. Its clearly important to make sure the correct sails are active for the correct set of sample periods otherwise the sail performance data will be inaccurate. Our approach is to review the sail usage as part of our post race analysis. We compare our track (windward/leeward etc) with the sail data on Boat Configuration Tab on the diagnostics tab later. Where the two don’t match up we can edit them using the Bulk Boat Config Edit panel (described later in this guide).

This shows the route that the boat is set to follow and its current next waypoint. As with the Boat Config Items you can edit the active status of a Route Waypoint – you can have a Waypoint in the route sequence that is inactive, for instance, because you decided to by pass it. You can also edit which is the next Waypoint. Stepping off the record will save the change to the database.

You can also open the full Route Edit screen or export the route to csv file.

Tab Eleven: Diagnostic

The diagnostic data tab contains panels that make it possible to review and edit the data that Rockit has captured.

NMEA Data Panel

Displays the information that the Rockit has derived from the NMEA messages received and loaded into its database. Each row in the list represents a single message received.

Rockits NMEA Data table contains basic information about the sentence and a set of fields to represent the data points in the messages, The aim with this table was to collect enough information to drive the calculation process that drives the summary and polar data creation. In theory an NMEA 0183 message can contain up to 50 data points so we should have 50 data columns in the table. In reality we found that the message types we were collecting only required 40 columns maximum. NMEA 2000 messages are collected in a similar way with the messages being broken out into their sub-components and stored in individual fields.

The Sentence name drop list contains the sentence names that are used in the calculation process. Rockit can be set to run in two modes. One where all the received messages are collected and stored or one that only stores the messages that are required in calculation. Unless you have another use for the data outside of Rockit there isn’t anything to be gained by collecting and storing message types that we don’t use for calculation. There is a parameter value set to force Rockit to collect all inbound sentence data.

The following functions can be applied.

1. Filter by Message Type. The Sentence drop list at the top of the screen filters the sentence displayed. Only one type of sentence is displayed at a time unless “No Filter” is selected. Once the Sentence has been selected in the drop list the ‘Refresh NMEA Data’ button needs to be pressed to update the data displayed.
2. Sort By and Sort Order. Use these values to sort by something other than the default sort on the Record ID Column. Sort by is the name of the column to sort by. Sort Order determines whether you are sorting Ascending or Descending on that column.
3. Filter by Date and time the message is received. The Start Time and End Time can be entered using the dialog boxes. Pressing the Refresh NMEA Data button will then return the message that appear within a specific time period.
4. Filter by Value. If you know the value that you are looking for you can use the query value field to filter on. As with the previous filter types press the Refresh NMEA Data button to return the filtered records.
5. Filter by a combination of Time, Value and Message Type. The different filters can be used at the same time to make an even finer grained filter.
6. Deleting Single Messages. We found on our test boats that occasionally messages would get corrupted and that it was useful to be able to edit or remove the erroneous values. We found that the erroneous data would cause spikes in the Polar and Wind/Boat speed profiles. Pressing ‘Delete’ will permanently remove the record from the database
7. Deleting All The Displayed Messages. The Delete Displayed Data button will remove all of the currently displayed NMEA records from the database. This is particularly useful if for instance you have recorded data whilst motoring at the end of a session. You can use the time filters at the top of the panel to select the records between a get set of times, then use the Delete Displayed Data to remove all the records for that time span.
8. Editing Data Values. It’s also possible to edit the individual NMEA message records. Rockit will filter out a lot of data corruption, but some elements will inevitably still get through. Clicking on any of the cells in the table apart from Record ID, Created Time will allow you to edit the value. Having made the change click on another cell in the table to save the data update to the database.
9. Recalculation Of Summary Data. Once you have removed/edited the values you don’t like you will need to recalculate the summary data. This is achieved using the ‘Recreate Session Summary’ button on the Session List screen. If you have a long recording session it can take some time to recalculate all the summary data values. You will not be able to record from the NMEA source until you have finished the recalculation processing.

Raw Summary Data Panel

The Raw Summary Data Panel displays the data calculated by Rockit from the incoming NMEA Data feed. Effectively it is a different more limited view of the data on the processed summary data panel. Unlike the Processed Summary Data panel the timeseries runs down the page, each row represents a timeslot. Its is also possible to edit the values on this panel. Whilst its better to perform a complete recalculation of the data, something that is described elsewhere in this guide if you are looking for a short term fix for one of the graphs editing the summary data can be useful.

Making changes to the Raw Summary Data will not affect Polar data for a session or boat as that requires a complete recalculation of a sessions summary data to affect.

Editing values is simply a question of clicking in the cell for the number that you want to amend, making the change then stepping out of the cells by clicking elsewhere. Clicking out of the cell will force the change to be saved to the Rockit database. Once you have completed the edit use the Update Displayed Data button on the left hand panel to update the information held on the screens.

You can also;

1. Export Raw Summary Data. You can export the Raw Summary Data as a csv file using the Export Raw Data button.
2. Update Display. Pressing the update display button will update the screen display.

Processing Errors

A lot of data errors will be picked up in the process of collecting and aggregating the data from the NMEA Messages.

A subset of those will be written to the a table called Debug Event. This list of errors for a session can be viewed on the Processing Errors panel.

Most of the errors are quite technical. If you are experiencing difficulties collecting data then the explanation is likely contained on that panel. You can Export the rows for a session using the Export Processing Errors button that will create a csv file of the errors that can be sent to Rockit support via email. Email support@ashtree-marine.com

A note on Purging Debug Events. Over time the Debug Event table can get very large and that will slow the processing of the Rockit data. You can use the Purge Debug Data button on the Session List Screen – Session Utilities tab to clear all but the most recent data out of the Debug Event table. If there is a lot of data in the table this may take some time. Once deleted the Debug Events cannot be retrieved.

Tab Twelve : Log

The final tab will display logging information as data is collected. In this case running on the Rockit Server version of the software viewed through VNC viewer you can see the NMEA 2000 messages that the server is receiving. They will be extracted and stored in the NMEA data table.

Problems connecting to a data source will be visible here as will error messages that are generated.

Once the recording session finishes this log output will be lost. It mostly exists as a “am I collecting data” check.

Notes On How To Use The Graphs

If you right click on the actual graph you will get a context sensitive menu appear. This gives you the option to both save the graph as a .png file, Zoom in and out on the graph axis and so forth. It also gives you the option to modify the graphs visual properties; change the way that the graph is displayed. For instance; you can rotate the axis, change the font, background colour and so forth.

Its worth noting that the original properties will be restored when you update the sail plot the change in appearance is not stored for future use.

Each individual graph panel can be manipulated in this way.