Before buying a Garmin network cable be sure to look at the size of the ends. It may be a problem for you. Some people just run an non terminated ethernet cable, then buy the kits to put the garmin connectors on. That's also a possibility with your raymarine cable. You could cut the Raymarine connectors off and put Garmin connectors on. Before cutting it you need the color code Raymarine uses. Hopefully it conforms to ethernet standards. If so then the connector kits may be the way for you to go. You might find someone who would loan you an RJ45 crimping tool. Download the instructions and see if this is something you would be comfortable trying.