Splicing Raymarine Seatalk HS networks

[Ric]

I have a Raymarine E7D MFD connected via Seatalk HS to a Raymarine Digital radar. I want to add to this network an A-Series repeater at the helm.

The Raymarine solution is to buy a Raymarine Seatalk hs switch (about £300 and a bulky thing which I will have to squeeze in somewhere) and two absurdly expensive Seatalk hs cables (which have big plugs on the end which I will have to cut and splice in order to install).

Can I just splice together the three units? It is just ethernet cable after all, and I will have to cut and splice the cables anyway due to the bulky plugs).

 

[laika]

I think it's just fast ethernet. If you're cutting the ends off anyway, crimp RJ45s on and use a cheap ethernet switch in a dry place.

[EDIT] I should add a disclaimer that my own seatalk hs "network" is currently just a single cable from the plotter (not having radar or a second plotter) so this is only "what I'd try" rather than "what I have working"

 

[Lon nan Gruagach]

The info here http://www.raymarine.co.uk/view/?id=3838 has a few gems hidden away.
Yes SeaTalk hs is plain old ethernet and Raymarine's "hub" is in fact a switch (data only goes to the destination node instead of with a hub which sends all data everywhere).
The other gem is "only 25 devices can be attached, this is a good indication of the netmask that Raymarine uses 255.255.255.224

 

[Cardo]

I would recommend making up your own ethernet cables (as I have on my boat) so they're all the appropriate length, and at a small fraction of the cost of Raymarine cables, and use a small ethernet switch which you can power from 12v.

Don't splice more than two ethernet cables together, that's a recipe for disaster.

Edit: The proprietary, waterproof plugs Raymarine uses to connect to their radars, plotters, etc. are more of an issue. I have a short Raymarine waterproof plug to RJ45 patch cable plugged into an adapter (or you could just splice them). Not cheap at around £20 or so at the time, but still better than buying their 10+m cables.