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Triquetra 07-06-2011 06:13 PM

Nav Rule Question on the Use of Radar on Sailboats
The Nav Rules state, "Every vessel shall maintain a proper look-out by sight and hearing as well as by all available means appropriate in the prevailing circumstances and conditions so as to make a full appraisal of the situation and of the risk of collision."

So, does this mean that the radar has to be kept on whenever underway or just when conditions warrant it? Since the radar is a large draw on the batteries when under sail, it does not seem reasonable to run it during the day, in good visibility, risking having all of the instruments down when they are needed. I would appreciate any clarification from those of you with a lot of experience in this area. Thanks in advance.

turbulicity 07-06-2011 06:24 PM


Originally Posted by Triquetra (Post 747425)
appropriate in the prevailing circumstances

So, no.

jrd22 07-06-2011 06:29 PM

I have heard that if you have radar and it's not on it will weigh against you if you are involved in an incident. That doesn't answer your question, but there's a lot of gray area in maritime law.

svHyLyte 07-07-2011 10:00 AM

I have been sailing for over 50 years on both coasts of the US as well as Mexico and in the Caribbean and in all of that time have never heard of a private yacht being held liable for a collision for want of using a radar. In fact, many of the people I know that have radar really don't know what they're looking at much of the time and wouldn't know how to plot a target if their life depended on it. The folks that seem most knowledgeable about their radar usage all seem to be either ex-military or from areas where there is much fog and reliance on the device is more common.


jackdale 07-07-2011 10:08 AM


Rule 5 does not require the installation of radar, but if radar is installed it must be used whenever it would contribute to the quality of the lookout. What are your obligations if radar is installed on your vessel but is not working properly? Rule 5 does not require that mafunctioning radar be used. If the problem is temporary, such as signal blockage caused by a heavy rainstorm, the use of radar can be suspended but not abandoned.

There is a much longer explanation on the site.

jackdale 07-07-2011 10:09 AM


Originally Posted by jrd22 (Post 747431)
I have heard that if you have radar and it's not on it will weigh against you if you are involved in an incident. That doesn't answer your question, but there's a lot of gray area in maritime law.

Too true. When I pose that type of question to my buddies at Transport Canada, the response is usually something love "The courts will decide."

Donna_F 07-07-2011 02:44 PM

Having radar means you should be even more able to prevent a collision so in a way it increases your responsibility as the boat owner.

nolatom 07-07-2011 05:42 PM

If you failed to see something your radar, if on, would've seen, then you probably haven't lived up to what Rule 5 says about "all means appropriate to the circumstances".

But if you already saw what radar would've told you was out there (the "bright sunny day"), then you didn't need radar to "help", and likely wouldn't be faulted for not having it on, or using if it was on--the collision was caused by factors other than your lookout.

Different situation, though, if it's restricted viz or obstructed view behind your big jenny while you declined to use radar, and the radar would've seen what you didn't.

Note also that Rules 6 (safe speed rule) and 7 (determining risk of collision) have additional requirements for vessels "fitted with radar". So if you have it, you have to use it, or at least take its capabilities into account.

The article Jackdale linked give much more explanation about all this.

Betcha the courts will find the same principle applies, rules or no, about some of the newer stuff, like AIS, to find out who's out there and communicate with them if in doubt.

The lookout rule is vague on specifics for a reason--they don't want you to have your head stuck in a radar scope (at least in the absence of pea-soup fog) to the detriment of a good visual lookout, no vice-versa either. "Lookout" mean listening too, for signals or foghorns. Or for other vessels talking on the radio (if you have radio, which is whole 'nother topic in the same vein as radar). If you have all this stuff and can't effectively use it all by yourself, then you may be judged to have been short-handed if things went south due to incomplete lookout.

Donna_F 07-07-2011 09:50 PM

In the end, everyone is equally responsible for avoiding a collision or an allision (moving object hitting a fixed object). I think the fact that radar is specifically mentioned in the US CFR tells me that if it is installed that a lot of weight is given to it as a means of keeping a lookout. If I was involved in a boating accident, I wouldn't depend on my defense being that I didn't know how to read the radar properly.

Just my opinion.

Triquetra 07-10-2011 09:57 AM

I really appreciate the insight of all of you who responded to this, particularly Jackdale's link and nolatom's comment regarding the "vagueness" of the rule. Anytime there is a short, terse rule, I know there are pages of implications behind it. Thank you.

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