Report content
Report format
Submit a Test Report
Possible Errors

Report content

It's surprising how a report of even the simplest observations can be open to a variety of interpretations. When talking of the date and time, for example, do we mean the local time with any adjustment for daylight saving, or perhaps Zone, or Universal time? If we specify a compass course, do we give what the compass actually reads or is it corrected it for the local magnetic variation? When reporting boat speed, would that be our speed through the water, or the speed over the sea bed? When exchanging information between people from different backgrounds, cultures and experience, it is absolutely essential to be sure that we are speaking the same language. Fortunately, with marine weather reporting, there is already a widely used, internationally agreed standard that has been in regular use for many decades.

The World Meteorological Organization (WMO) Voluntary Observing Ship scheme (VOS) uses a system of encoding (BBXX) that firmly defines the parameters to be given in weather reports. It is these, with some small noted differences, that are used in YOTREPS reports and are as follows:

Parameter Units Explanation Note
Date and time UTC UTC (Coordinated Universal Time which for the purpose here is synonymous with GMT (Greenwich Mean Time)  
Position Degrees and minutes Report positions using separate single digits only. Give the latitude, as two digits of degrees followed by two digits of minutes followed by the name (i.e. North or South) Give Longitude as three digits of degrees followed by two digits of minutes followed by the name (i.e. East or West). For example a position of 28 degrees 5 minutes north, 45 degrees 17 minutes east, would be read out as:

Two Eight degrees Zero Five minutes North, Zero Four Five degrees One Seven minutes East

Boat course Degrees (true) Boat's course through the water. (Not necessarily the same as the boat's heading) 2
Boat speed Knots Average speed over the last 3 hours to the nearest whole number. Speed reported should be the speed over the ground. 3
Wind direction Compass points Direction of the true wind. To obtain this use either the Beaufort Scale or correct the masthead wind indicator reading for the boat's speed and course. 5
Wind speed knots Average speed of the true wind. To obtain this, use either the Beaufort Scale or correct the masthead anemometer reading for the boat's speed and course. 5
Wind wave height Metres A visual estimate best made on the side of the boat from which the waves are coming.  
Wind wave period Seconds Observe a small floating object such as piece of wood, patch of foam or a bird and begin counting seconds as it reaches the crest of the first well formed wave. Stop counting when a number of crests have passed and obtain the period by dividing this into the time lapsed.  
Swell direction Compass points Direction of the main ocean swell.  
Swell height Metres Vertical distance from trough to crest and the average of the larger well formed swells.  
Swell Period Seconds Measure as for wave period.  
Cloud cover % Proportion of the sky covered by cloud. 4
Prevailing visibility Nautical miles This is the "maximum visibility common to one half or more of the horizon circle". 6
Pressure hPa Barometric pressure.  
Pressure tendency + or - hPa Pressure change over the past 3 hours. Prefix with a plus or minus sign to indicate rising or falling. Report 0 if steady  
Air temperature °C Should be measured on the windward side of the vessel. The thermometer should be shielded from radiation, rain and spray.  
Sea temperature °C Temperature of a freshly collected bucket sample of surface sea water.  


  1. The style: Twenty Eight degrees Five minutes North, Forty Five degrees Seventeen minutes East is a little shorter but is more difficult to understand over a poor radio link and should not be used. Never use the word 'decimal' or 'point' to separate the degrees from the minutes field. This implies that the position is given in degrees and decimal degrees; an alternative format widely used in marine forecasts.
  2. The course reported should be obtained by correcting the compass heading for deviation, magnetic variation and leeway.
  3. Except when in a strong current, which is unusual on an ocean passage, speed over the ground will be very similar to speed through the water and could be measured by electric or mechanical log, GPS set or visual estimate. Remember to report the average and not peaks that might perhaps occur when surfing down wave fronts.
  4. To estimate cloud cover imagine the sky divided into quarters like a cake. Imagine each quarter further divided into two parts; each segment forming one eighth of the total sky. These are known as oktas and are the unit of cloud cover used by professional observers. Perhaps because the okta is not widely familiar, cloud cover is often reported as a percentage. Multiply the number of oktas by 12.5 to convert to a percentage.
  5. For more information see: Wind Speed Notes.
  6. When the horizon appears clear and sharp, use your height above sea level and the following table to estimate the distance to the horizon:
Height of eye above
sea level
Distance to the
(metres) (feet) (Nautical miles)
2 6.6 2.9
4 13.1 4.1
6 19.7 5.1
8 26.2 5.8
10 32.8 6.5
12 39.4 7.2
14 45.9 7.7
16 52.5 8.3
18 59.1 8.8
20 65.6 9.2
22 72.2 9.7
24 78.7 10.1
26 85.3 10.5
28 91.9 10.9
30 98.4 11.3

When the visibility is not uniform in all directions, determine the prevailing visibility by dividing the horizon circle into sectors of visibility. Estimate the highest visibility common to one half or more of the horizon circle.

Report format

If you are passing your reports through a radio phone net (e.g. Pacific Seafarer's net), you can skip this section. If you're using Winlink or Sailmail the the position report form that is included within your Airmail software provides an easy way to send your reports and takes care of all formating and address issues. (Be sure to use the current version and to tick the check boxes for "Marine Report" and "Send to YOTREPS")

If you are using some other marine email service then this next section is for you.

Position and weather reports forwarded to the list must be in plain ASCII text. By default, some email programs use HTML or Rich text which is unacceptable though plain ASCII text is usually available if you check the settings. ASCII is font independent and economic to send. More than you ever needed to know about is is given here.

The Reporter software is designed specifically for producing correctly formated reports. It can produce reports in several alternative formats, can plot positions on its own chart and has many associated features.

Although convenient, use of the Reporter is not essential. Because YOTREPS reports are simply plain text documents they can be prepared with any basic text editor such as Microsoft Notepad. When preparing reports in this way it absolute adherence to the format specification is absolutely crucial. Small changes such as missed characters, spelling mistakes, extra blank lines or spaces can cause the report to be rejected. Here is an example of the CLASSIC YOTREPS format alone with an explanation of each line:





1 Must contain the word YOTREPS in capitals.
2 The UTC (i.e. GMT) date of the report in day/month/year style as above
3 to6 Column headers as above
7 & 8 Report lines. In this example there are two but there could be 50 or more. Report lines
are followed by a blank line, then a line containing the word "Comments". Comments are
optional and ignored by the read back software. If you include anything here, please
keep it short.
Lines for comment text. Please note that this section is not read by YOTREPS and is included to give compatibility with an earlier format. If you wish to add text to your report use PostCard Notes. See the List Server Help File for details




No A number that identifies the report line.
CALL A name or call sign that's used to identify your vessel. Choose whatever you wish but it should not be confused with another vessel and must not be more than 8 characters in length
TIME UTC The UTC/GMT at which the report line was made.
POSITION Whole number degrees and minutes or Latitude and Longitude with the N or S and W or E identifiers exactly as shown above.
BOAT Cse Mean course over the past 3 hours shown in degrees true.
Your average boat speed over the past 3 hours in knots.
WIND Dir The closest cardinal or intercardinal point from which the wind is coming from. This is the true wind direction (i.e. not apparent).
WIND Kts The wind speed in knots. This should be the mean speed - a single number eg 12 and not a range such as 10-15
SWELL Dir The closest cardinal or intercardinal point from which the primary swell is coming.
Cld The estimated percentage cloud cover.
Bar hPa The barometer pressure in Hecto Pascals
Trend The barometric pressure tendency. Should be the change in hPa within the last 3 hours. Use + or - to indicate rising or falling, 0 if steady.

Submit a test Report

Please contact Pangolin tech support for the address to send your test report. Tests should be made using the marine email system that you'll actually be using while at sea. Their purpose is to check that the format will not be rejected by the automated report processor. If no difficulties are found, active passage reports can be sent to the list server address as follows:

List server address:

This address is not for regular corresondence and should only be used for posting reports and YOTREPS e-mail list services

Possible Errors

Reports submitted to the web server e-mail address are screened for errors before they are saved to the data base and plotted. Use of the Reporter software to format your reports is strongly recommended as most errors will be avoided. It's not possible to detect all errors but here is of list of the more common problems:

1. The date and time show that the report was more than 24 hours old or set into the future.
2.  The position given contains out of range values or was incorrectly formatted.
3.  No weather observations were included in the report.
4.  The report was from an inland location, Port or anchorage.
5.  An earlier report was received within the last 18 hours.

When errors are found, an automatically generated e-mail is posted back to the sender giving an indication of the cause. In general expect to hear nothing if your report has been entered into the system without difficulties.

How to view your error log

Send a message to the list address (see above) with just the words "LOG ID" (without quotes and where "ID" is your YOTREPS identifier. Within 10 minutes the list server will post back to you a list of the error status on your last 10 reports.