[Mee-n-Mac]

Probably not too surprisingly I have some thoughts on what might be reasonable speed limits that I've not previously spewed but now that the flood gates are open, here's some thinking for your consideration ....

The above posts by BI, Islander, Dave R and Winnilaker are interesting because there is a way to begin to reconcile these apparently opposite positions. First I'd like to state a few principles and concepts that I think we all can agree to. First is that everyone should be operating their boat so that it doesn't cause injury to anyone else. Second it is the sole responsibility of the captain to accomplish this. Third any speed limit to be set*, should be set such that the actions of a reasonable person, acting in accordance with the above principles, aren't unlawful. Let me explain the last bit in more detail. Should there be a need to limit speed, the limit isn't set that such a one eyed sailor, blind drunk in his good eye, will always be able to avoid the collision (ie - limit too low). And the flip side is that any limit shouldn't require the operator to be Superman with x-ray vision, reflexes faster than a speeding train, etc, etc. A normal, reasonable, human person has to be able to avoid the collison. Typically these things are set at the 85% percentile, that is 85% of the population can do what's required. Lastly, just as we do on roadways, the limit isn't set according to the worst case environmental conditions. Expounding on this you don't set the posted maximum limit for foggy, raining, etc, conditions. You set for the normal conditions and while what's prudent and reasonable will vary with those conditions, it's the duty of the operator to slow down in accordance with the conditions. The roadway corollary is that when the road is slick with snow, the enforceable limit (you can be stopped and fined) is lower than the posted limit and it's the driver's responsibility to know this.

Given the above, what factors determine whether a collision will occur or not. Certainly the ability to see the hazard is prime and so at what distance can a reasonable person see the hazard ? This is largely independant of speed. Does the available sightline (how far can you see) exceed this distance ? How long will it take the operator to perceive and react to the hazard ? And lastly how much distance does the required control action (slowing or turning or both), to miss the target, take ? Combining all these, at some speed even Superman can't avoid the collision because his sightline is restricted or he, and/or the boat, can't react fast enough. And the other side at some speed even a drunk sailor is virtually guranteed to avoid the collision. In between these 2 speeds is where the reasonable man can avoid the collision and where the speed limit, if necessary, should be set.

Now there are a lot of gray areas and specifics that I've left unsaid but if we can't agree on the general concepts above there's no reason to get into them. *Also I've left out the practical issue of whether a limit, set in accordance with the above, is necessary or will accomplish anything. For the moment let's leave that discussion on the side.