The Commodore has two safety items for Red Ranger.

• Class B AIS Transponder.

• Radar.

We've got a good AIS receiver in our Standard Horizon GX2150 radio connected to our Standard Horizon CP300 chart plotter.

But that's not a transponder. We're only visible to big ships as a radar blip, not a proper AIS track with a Point of Closest Approach (PCA.) We like seeing big ships as a detailed AIS track. We think it might help us if big ships could see us that way, too.

We need to start the budgeting process for the large piles of money involved.

There are two transponder approaches: dedicated antenna and splitter. The dedicated antenna would have to be run up a mast.

We already have two VHF radios that share one antenna with a splitter.

However. I'm not sure our ancient antenna splitter is really up to the demands of the new AIS and DSC requirements.

I think the simplest (but more expensive) is to get a class B transponder and a splitter. I can replace the old splitter with the new AIS splitter. I can replace the spare radio with the AIS transponder. I think that gets us up and running with almost no wiring changes to speak of. I think I can even leave the old radio in place. If we need it, we can just move the antenna wire from AIS transponder to radio.

Two of the splitters available (Vesper Marine SP160 and Digital Yacht SPL2000) also provide AM/FM antenna capability. That's very appealing, since we have an AM/FM antenna wedged up behind the cabinetry. Removing that antenna would reduce electrical clutter a bit.

I like the Si-Tex MDA-1 transponder because it has it's own internal GPS antenna. There's a certain elegant simplicity to avoiding holes in the deck. But the Vesper XB8000 seems somewhat cooler because it has a WiFi interface to the iPhone or iPad. The idea of getting GPS position via WiFi is appealing. However, this may require drilling yet another hole in the deck for the external GPS antenna.

It's remotely possible that the antenna will work below decks — our other GPS antennas work below the deck. We have a Bluetooth GPS antenna from Dual; it was invaluable when using the iPad to navigate. It seems to work below deck.

Radar

The Standard Horizon can interface with a Si-Tex Radar. The choices include the smallish MDS-1, and the larger MDS-8. There are others, but they get big and expensive.

This is one of those items that we've needed on a few occasions. Very few. While a big, accurate radar might be kind of fun, it's also a power hog. While the small cheap MDS-1 radar might fit our budget, it seems like we shouldn't go too cheap on safety. On the other hand, it's only supplemental to eyes and GPS. On the other hand, a large, super accurate radar on a tipsy sailboat doesn't make much sense. A giant MDS-10-5 (with a 5' open array) is going to be really accurate, but only on a low, stable trawler.

Another subtlety is getting the platform properly level on the mizzen mast. A self-leveling bracket costs as much as the radar itself! Without a self-leveling bracket, we'll miss targets on the weather side of the boat because the radar's sweeping up into the air; and the range on the leeward size will be limited because the radar's pointed down at the water.

I guess the good news is that we can always replace a fixed bracket with a self-leveling bracket if we experience serious range problems.

It appears that the Si-Tex radar installation involves putting a bracket on the mast and putting the radar on the bracket. This involves hanging 20' above the deck and using power tools without dropping anything into the river. Getting things level seems challenging, but not impossible. Maybe I can tape the level to the platform so it doesn't fall off.

Once the radar's up there, we have to figure out how to run a wire down the inside of the mast, through the deck, and to an interface box between radar and chart plotter. This appears to involve drilling holes in the mast and dropping a string with a lead weight to help fish the wire down through the mast. I've put waterproof clamshells on the deck before; that's not too hard. I was looking at Creola's aft deck: they've got at least three separate wire bundles coming out of their mizzen and going through clamshells into the aft cabin.

The paperwork sure seems simple enough. We have a number of spare circuit breakers that can be used for radar. An on-off switch is required, also. None of it seems too daunting. Maybe I'm missing something. Maybe there's some subtlety to this.

Update

The crew of Indefatigable shared the Practical Sailor AIS comparisons. That was helpful and got me started down the road to this report:

http://www.milltechmarine.com/customer_center/pbo_ais_test_jan.pdf

Wow. That's a detailed blow-by-blow comparison. Nice.