"Donal" wrote in message
...

OK! Let's try to rewind a bit.

Why did you ask where in the CollRegs it said that you couldn't navigate
under Radar alone?

The ColRegs are explicit that a lookout is required - I said precisely that in
the very next sentence. And the ColRegs also require a safe speed. However,
nowhere is there an explicit correlation made that requires that a safe speed is
some exact function of the degree of visibility. Before radar, attempts where
made enforce such a formula ("stopping distance shall be half of the
visibility"), but that was rejected by the courts. There simply isn't anything
that explicitly says that all ships must stop when the vision is reduced to
below the stopping distance from minimum steerageway. With a proper radar
setup, vessels are allowed to continue at a speed that would not be prudent
without radar.

So, what this means is that although a visual lookout is required, the vessel
can actually be "navigated" by radar. More to the point, the helmsman, who is
likely focused entirely on radar and/or the compass, is not even permitted to
also function as the lookout. How much input does the lookout provide? In a
real pea soup, probably none if all goes well.

Now, you might argue that the implication of various phrases in the ColRegs is
that the "letter of the law" is that no movement is legal in pea soup, the
courts have not seen it that way. And if you insist that this "letter of the
law" is all important, overriding everything else, I might ask where in the
ColRegs there is an exception for vessels anchored, moored, or even in a slip?
Rule 5 simply says "at all times," it doesn't say "when underway." In fact,
the courts have ruled that a "proper lookout" is satisfied by "no lookout" in
many situations. (Though there have been odd cases where the courts said that a
boat anchored near a channel needed a lookout to warn off other boats.)

The point is, the concept of what is a proper lookout, and what is a safe speed
is rather variable. The courts have clearly held that if there was a
reasonable chance that a better lookout might have prevented a collision, than
the vessel is held liable. But if a proper lookout is posted, the vessel is
permitted to effectively navigate on radar alone.



That question confused me. It suggested that you were looking at the Regs
with preconceptions. IMHO, the CollRegs are very clear about the
requirement to keep a lookout.


Indeed. The ColRegs is so emphatic that no exception is given for vessels
anchored, moored, or even in a slip! So are you in violation now? Don't you
believe in the ColRegs?

The lookout is required, but he isn't the one driving the boat.



So, Jeff, Why did you ask me "So where in the Colregs does it say you can't
run on radar alone?"

What did you mean by that?

This time, I've also pasted the rest of the same paragraph. Here it is.
" Of course, one should always have a visual (and sound) watch, but that is
moot if there is
effectively zero visibility. "


I meant that although the lookout is required, his contribution to the actual
driving of the boat will be minimal. The helmsman is relying on radar alone.
If it truly is "zero visibility" this is rather obvious. (Of course, the fog
often varies so that if the fog lifts, the lookout may get a chance to
contribute, but then it isn't "zero visibility.")

BTW, how is this different from your "blind navigation"? The whole premise of
that is that its possible to navigate with no external inputs.