Sailing without AIS or Radar

[boatman61]

Originally Posted by nortonscove

Sorry but I don't think it's possible to sail without such equipment. I'm not aware of anyone in history sailing without these items. Since the advent of sailing no one has been so foolish.

[Dan Mosby]

S.F. means fog, so I'd go with RADAR.

I'd install it and then do some local training runs to learn how to use it and what each ship type return looks like.

[Mauruuru]

No instruments? You’ll need a vhf so for a few bucks more get one with AIS

[sailingharry]

Radar is nice, of course. Very nice. It came on my new boat (and if it wasn't a recent unit, I would have upgraded) and I'm spending a lot of time getting to know its temperament.


However, I'm not sure how well it fits into the scheme of a 20' sailboat. That's a lot of power consumption, a lot of weight, and a lot of space. Figure he's got, what, a 10hp diesel driving a 30A alternator? House battery is probably a single Group 24? Boat weighs maybe 3000 pounds? What does a 20lb radar 10 feet off the deck (half his mast height!) do to stability, roll, etc? And at a mere $1500, that's what, 10% or more of his boat's value (to be fair, AIS transponders seem to be crazy expensive)?


Radar does allow him to see everyone -- but no one can see him. His radar return at 5 miles (where a freighter needs to start thinking about him) is zip. And if he sees and identifies a collision risk with that radar, his ability to respond is minimal if non-existent (5 miles at 20 knots is 15 minutes!). Remember, his top speed is probably under 4 kts under power. As a tiller steered boat, working a radar is challenging. And avoiding a freighter who can barely identify your position leads to confusion on the freighter's bridge, not a good thing.



Haven't seen many rocks move, or even buoys on them, so the radar doesn't do much for that. Chart plotter does a MUCH better job of avoiding the rocks (especially the ones 2 feet under water). About the only thing a radar does really good is avoiding the other small slow moving boats.

[David M]

Cut back on what you plan on spending on either and get both One does not replace the other. Get a good plotter that interfaces with the AIS and radar and get a good fluxgate so you can plot contacts on your radar that do not have AIS.

Radar is an excellent aid for plotting relative motion lines.