I think brookhouse are haphazard about replying to
email. I didn't get a reply to an enquiry I sent about 3 years ago. A
boat I've been
racing on this year had one installed recently. I don't know the owner well enough to start ripping out his
electronics to take a closer look but he's very pleased with it, as were the other couple of people I've met with earlier (non-wifi) versions. From the blurb they seem technically well thought with added flexibility form being able to upload little scriptlets.
Popular alternatives people seem to mention include the
shipmodul and the slightly more home-brew but apparently very good value
vyacht.
I don't *believe* (but do check if you care) that any of these are officially licensed from Raymarine and I *think* (again: could be wrong) that they all base their conversion on
Thomas Knauf's reverse-engineered seatalk information.
Note that the conversion between sea talk and NMEA-0183 isn't one to one. Often one NMEA-0183 sentence may be composed of data from several seatalk messages so a poorly implemented algorithm could give you a lat and long composed from two bits of a different fix, but hey, if it's my
boat it doesn't go too far in one second.
You might want to check which sentences are converted by your chosen product, whether that matches your software's requirements, and whether the conversion is bi-directional. Seatalk->NMEA-0183 is easy. The other way requires the device to implement the seatalk
collision algorithm so is a bit harder.
Most of the non-raymarine converters being (I believe) constructed from the same information, I think they mostly convert the same messages.
I'll second nigel1's suggestion if
wifi is not needed. The yapp one is about the cheapest option there is. The Raymarine one (if you can find it second hand) is probably the only one written with the definitive seatalk reference available.