SeaMarks Earth with X LOGO

SeaMarks by Andren Software Co.

Manage your fishing or diving hot spots.


The Andren SeaMarks® program is waypoint management software for Windows.  It is a tool for you fishermen and divers to manage all your electronic navigation waypoints (readings or marks) in your computer and easily move them in and out of your GPS (chart plotter).   It is easy to use and will make your waypoints work better for you. Its features allow you to plan fishing/diving trips that save time and fuel and to analyze your waypoints for promising areas to explore.  It works with LORAN, GPS, GALILEO, GLONASS, and BEIDOU data.  In this website, I will call all the Global Navigation Satellite Systems by the name GPS as they all use Latitude and Longitude data.  This waypoint mapping software and waypoint conversion software, can do Loran to GPS conversion easily and accurately.

SeaMarks lets you to easily move your data into and out of a GPS via a memory card (SD) transfer or a cable transfer. This means you can move your points from one GPS brand to another or keep two different brand GPSs synchronized.  You can print an organized book of listings and maps to take with you to help select your spots.  

SeaMarks was previously known as LoranGPS, and before that, the Loran/GPS program, and even before that the Loran program.  


•  Manage your waypoints, routes and tracks on the computer.

• Import waypoints, routes and tracks from a variety of GPSs

• Export waypoints and routes to a variety of GPSs.

•  Convert Loran readings to GPS waypoints

•  Print your book with spreadsheet listings and charts.

 • Coordinate your book with your GPS track plotter

• Import or export a large variety of data file formats for compatibility with other programs.

• Convert waypoints and routes from one GPS format to another.

• Display your points in a variety of formats

Simple Chart showing St.-Pete-and-middle-grounds
Display your points on a simple chart with Loran and Lat/Lon lines

• Identify waypoints with Name, Description, Rating, Color, Icon, Depth, Group, Date, and Comments 
• Accept and display GPS Lat/Lon in a variety of formats. 
• Color the waypoints on listings and/or graphics.
• Sort your waypoints numerically or alphabetically on any column• Display your list in pre-formatted or user customized spreadsheet styles and find duplicates.
• Group your waypoints to make it easier to find them in your GPS.

Conversion service

Conversion service is available if you don't want to buy the program, but just want to get some Loran points converted or points moved from one brand of GPS to another. The cost depends on the work needed. If you do the data entry, it is much cheaper. If your data is in electronic form and can be copied and pasted, then you get a flat rate of $30.  If you send a list that has to be typed in by us, then the rate depends on the number of waypoints.  Call or write for a quote.  Indicate what form your data might be in. 

Carl with 13# LobsterCarl with 51# grouper

Company History

The Andren Software Co. has been publishing this program since 1986 and has incorporated many features requested by users. The program gets updated frequently to add improvements in the operation of the program and to remain compatible with new Windows versions and new GPS models as they come along. We always strive to make the program usable by those who have little knowledge of computers or have no feeling for Loran or GPS. The program comes with a 16 page mini-manual edited by Carol Andren for clarity and understanding.  You also get a soft copy of a printable 130+ page manual that is also the basis of the help menu.

Carl Andren, the creator of this program, is a member of the Institute of Navigation, the International Loran Association, and the Institute of Electrical and Electronic Engineers. He holds 26 patents in electronics including some on the technology known as WiFi.

The program has been re-branded several times to follow the progression of technology.  It started out as The Loran Program when Loran was the only means of electronic navigation.  When GPS came along and began to make inroads, the name was changed to The Loran/GPS Program.  Later that was shortened to LoranGPS.  Now that GPS is the only thing used by fishermen, the Loran-centric name was changed to SeaMarks (think wet landmarks).  



Version Updates


Made some minor updates


Fixed PCWindPlot import algorithm . Also made sure the program was "signed"


Fixed the Replace function which had Color and Symbol swapped


Made improvements to import routines for Humminbird HWR and Garmin GDB that are for very old models.   Also made changes to the Furuno NavNet3D importer.


Made small improvements like warning messages.


Fixed  issues with importing a Furuno GP1971F  file causing an overflow error and the Fish32N tracks importer that had spurious .points.


Fixed the Export of Raymarine GPX format that was getting dates wrong.


Added import for an Italian track plotter named Fish32N.


Added Furuno TZD and FurunoGPX to the import form GPS definition so as to load the appropriate icons.  Made a new Garmin GDB importer that does not use GPSbabel.  Fixed an issue where Symbol and Color were swapped in the Finder list so that they did not work right. 

See History for a list of all the updates since version 2.3

5/13/19 Big change!  We switched to a virtualized mode for the program.  This involves combining all functions, resources, and libraries into one executable (boxed app) that does not have to be "Installed".  Thus, the program can run on a removable disk (flash drive) as well as the usual location on the hard drive.  As for the hard drive, we supply a simple 'installer' that creates a place (folder) for the program on the hard drive, copies the program there, and creates shortcuts.  While the experienced customer could do this, many of our customers are not comfortable with these operations.  The version is now 10.2 and if ordered on the USB flash drive, you can run it there immediately if you don't want to put it on the hard drive..  

The program has been maintained and improved frequently.  If you have an older version, check with the  Change History page to see details on the changes in the program since your version was shipped. The version number is not incremented for small changes, only large ones.