speed limits

[Sally]

Lately I've been hearing a bit about posting a speed limit on Winnipesaukee. I'm sure many would agree and many others would disagree about this regulation, but my question is regarding speed enforcement. Does radar work on water? I thought that in order to get an accurate speed rating, the radar had to be on a flat surface, or at least on something steady. Not sure if those MP boats would qualify as "steady." Maybe someone out there is a little more knowledgeable on this subject and could help me out... Thanks!

[Skip]

Hi Sally,

Contrary to some earlier posts stating differently, radar (when employed carefully by a trained operator))does indeed work on the water. What works even better, though, is the new handheld Laser units being used statewide (you may have noticed one of your friendly New Hampshire State Troopers employing such a device on a highway near you).

Dead on accurate and able to pick out individual craft at good distances. If speed limits are ever introduced, look for handheld Laser to be the tool of choice in on-the-water speed enforcement.

Skip

[Mee-n-Mac]

Originally Posted by Sally

Lately I've been hearing a bit about posting a speed limit on Winnipesaukee. I'm sure many would agree and many others would disagree about this regulation, but my question is regarding speed enforcement. Does radar work on water? I thought that in order to get an accurate speed rating, the radar had to be on a flat surface, or at least on something steady. Not sure if those MP boats would qualify as "steady." Maybe someone out there is a little more knowledgeable on this subject and could help me out... Thanks!

The radar units would work about the same as they do on land. Due to their relatively wide beam they would be less prone to errors due to rocking and rolling of the MP boat. Conceivably you might find some error sources due to the more reflective nature of water vs land but practically speaking this isn't a big isssue. A bigger issue would be discriminating 1 boat from others and proving you nabbed the right person.

Lidar would be more prone to missing the target as the boat rolls about due to it's much smaller beam (think lidar/spotlight vs radar/floodlight) and would take more effort on the part of the officer to keep on target, but if done properly then the discrimination issue above is moot. Fog of course would reduce effective distances greatly.

Both devices only measure speed directly towards (or away from) the gun (closing/opening velocity). A boat (or car) travelling a speed S, moving at some angle relative to the gun will have a measured speed, M, reduced by the cosine of the angle (M = S x cosine{angle}, cosine{angle} < 1). This is always less than the true speed so you get a break in this regard. Just like on the roadway, the MP would have to pick it's spots to be effective. Time to add a power socket for the detector ?

ps - Military radars, which can track both relative velocity and position , would give true speed (no cosine error). I don't think the commercial radars in use are accurate enough for this to work though.

[Skip]

Ah, the engineer in you once again seeps out! Great technical explanation, including the fact that in almost all cases determined speed is actually less than that of actual speed.

Anyway, on water a typical handheld radar unit's range is much greater than over regular terrain, causing the operator to be much more observant due to the beamwidth and range issues covered earlier.

As you noted, Lidar can be a little trickier to use if the platform is not completely stable, but it has an extremely accurate aiming device and the dwell time on target is extremely short. And since you have picked out a particular target for speed determination, the time involved with an RF generating unit determining which target is the the actual return signal is eliminated.

Also, the platform used brings up an interesting point. Wouldn't it be intriguing if a large pleasure craft, or a non-decscript barge or even a strategic vantage point on an island were used as the observation point, with the MP units responsible for the stops being placed in a nearby discrete location?

Ah, its all a mute point anyway. There is no current legislation being proposed to even consider the speed limit issue, so we're likely years off before we ever cross that bridge....

But it is interesting to speculate how such a technology could be effectively employed.

[Lakegeezer]

Since the topic came up again , its worth putting in the opposing view. While a speed limit may be useful in certain areas of the lake, on certain days, it is not needed in most areas of the lake, most of the time. If some people's views must be imposed on others, it should be limited to summer weekends and only the congested areas. Take note that more people are injured while water skiing than being whacked by speeding boats.

[Mee-n-Mac]

Originally Posted by Skip

{snip} Also, the platform used brings up an interesting point. Wouldn't it be intriguing if a large pleasure craft, or a non-decscript barge or even a strategic vantage point on an island were used as the observation point, with the MP units responsible for the stops being placed in a nearby discrete location?

Ah, its all a mute point anyway. There is no current legislation being proposed to even consider the speed limit issue, so we're likely years off before we ever cross that bridge....

But it is interesting to speculate how such a technology could be effectively employed.

Not unlike the techniques used in ye bad olde days of the NMSL (55). When I was but a poor starving college student commuting to school, the MA State Police would place the transmitter/antenna on a pole mounted above the cruiser parked on the median strip just past a rise in the roadway. You'd never notice the pole and by the time you saw the cruiser it was too late. He would relay the info to other cruisers (sometimes 3 or 4) waiting 0.5 mi or so down the road where you'd actually be stopped and ticketed. Of course this was back when radar detectors were somewhat rare and the SP could sit all day, broadcasting away, and still catch people. Now-a-days I not sure this would be as effective. Then again I'm constantly amazed by the number of people I'll see hit the brakes just as they come abreast of a waiting SP cruiser, parked out there in plain sight. Don't these people look ahead ?!? Apparently not ...

On the lake it would be harder to hide w/o sitting on a island proper. The MP would have to introduce unmarked patrol boats. The VHF radio would become the CB of yesteryear, relaying Smokie's position to other boaters. Radar use would lead to detectors which would lead to lidar. W/o the revenue stream I wonder if the insurance companies would be as quick to help out the MP in funding their purchase. Aaargh ... it's the 70's again ...

[Mee-n-Mac]

Originally Posted by Lakegeezer

While a speed limit may be useful in certain areas of the lake, on certain days, it is not needed in most areas of the lake, most of the time.

You'll get no argument from me, I agree with what you said above. Just as we have differing limits for school, town, highways and interstates; the lake has differing conditions and thus differing requirements. A "1 size fits all" approach would find no support from me (and I don't think my boat could break any reasonable limit ). Moreover there are other rules I'd impose first that would, IMHO, make things better before I'd support a lake-wide SL.

*sorry for the title, been watching that Blazing Saddles DVD again, sorry folks, sorry ...

[madrasahs]

You may recall this post from Rob, re: measuring noise.

Originally Posted by Rob

Increase the measuring distance to 150' or more. Not only is this safer than the 50', but it more accurately duplicates the real-world condition due to the fact that boats are supposed to be 150' from each other, as well as the shoreline or any docks, swim floats, etc. Personally, I wouldn't want to be nearly that close to any object at WOT [Wide Open Throttle].

1) This fast, Big Boat business has already passed Rob's comfort zone with respect to the 150-foot separation rule. He is to be applauded for recognizing this. The problem is that there are too many Big Boaters who do not.

If passing a 150-foot stationary point is scary in these boats, what is it like for a "legal" 150-foot pass amongst multiple and moving points? (Meaning us, their "fellow boaters").

Is 150-feet a sufficient distance today? At today's unconscionable speeds, 150 feet takes less than 2 seconds to "close" on a moving obstacle (my boat).

2) Speed limit? Could the MPs possibly enforce such a speed limit?

Nowadays, Winnipesaukee operatives "welcome" boats that can exceed 100 MPH. Enforcing even a sensible nighttime limit would be fraught with problems identifying the offender by eye. A targeted offender could still continue on his way with his boat shrinking into the gloom at WOT (Wide Open Throttle).

If the reader hasn't gotten the gist of Winnipesaukee's most likely offending boats by now (and their operators' psyche), tickets are merely "the cost of doing business" -- just as we saw this summer with motorcycles and being ticketed for their illegal activiites.

[itchin for fishin]

Mee n Mac...help me out....what's IMHO?

[KPW]

Originally Posted by itchin for fishin

Mee n Mac...help me out....what's IMHO?

In my humble opinion

[Mee-n-Mac]

Originally Posted by madrasahs

{snip}

1)Is 150-feet a sufficient distance today? At today's unconscionable speeds, 150 feet takes less than 2 seconds to "close" on a moving obstacle (my boat).

2) Speed limit? Could the MPs possibly enforce such a speed limit?

{more snipping}

You raise 2 good points, let me take the easiest first. Certainly there are boats which can outdistance the MP's boats. This is also true on land wrt our cars and most of the cruisers the various PDs operate. And there are time and places when outrunning the law will be successful. Yet those facts don't stop the posting of SL's on the roads. I do believe that the majority of the time the MP will be successful in capturing the offender because it's not just an isolated MP boat but rather a network of MP boats (the old saying of "You can't outrun a Motorola" applies). A person who frequently offends is almost surely to be caught at some point, at least if he's docked on the lake. Now your question of "The cost of doing business" comes to the forefront (OK, 3 points). Certainly there are well heeled Ferrari and Porsche owners who think the same way. Yet the law allows for repeated offenders to be curbed via revocation of their liscence. A similar thing could (may already, perhaps Skip knows) happen with the boat owners registration. I would add that it's much easier to drive w/o a liscence than w/o a plate (or in this case, registration sticker). Nighttime enforcement, as you point out, may be more problematical but then again the MPs have radar to track non-stopping boats so perhaps strategies could be found to mitigate the problem. Whether the resources needed to effectively enforce a SL would be allocated is good question.

As to separation distance ... I don't disagree. Just as your following distance in a car should increase with increasing speed, so should your separation distance in a boat. What it should be is a bit harder to answer. Let me bring up one point for consideration. We are all (probably daily) exposed to a situation wherein the closing velocity meets or exceeds the 100mph mentioned above. If you drive a car down Rt11 along the lake you'll encounter cars running in the other direction with only yellow lines and much less than 150' separation. This usually works (though not always as an earlier post here on this forum showed) because most people act in a predictable fashion and follow the rule (keep to your own lane). Now boats aren't cars but similar thinking applies. Congestion, as well as speed, increases the desire for predictability. I've often been passed (overtaken & in opposing direction) by boats that violated my 150ft bubble. It doesn't always bother me because I've been able to assess the other guys course and determine that, barring some form of stupidity, no collision would occur. If separation distance is too be maintained in order to reduce the likelihood of collisions then I agree that the distance should be increasing with increasing speed but also would add that all boaters have a part to play in this. Just as you wouldn't turn across the yellow lines in front of an oncoming car, you have to operate you boat in a predictable fashion when in the presence of other boaters (and I don't mean Boston type predictability ).

[upthesaukee]

I think that Mee N Mac hits on one thing that makes the shrinking 150' zone just a little scary is the unpredictability of the other vessel (driver). In a car, we kinda assume (which can get us in trouble) that the other guy will stay on their side of the yellow line.

There are many times out on the lake when I feel like I somehow got stuck in the middle of a Joey Chitwood Thrill show, with vessels overtaking me two and three abreast, and just as many going the other way, and no yellow line for a "sense of security". Going in and out Alton Bay, Wolfeboro, Governors Island - Timber - Eagle Island area, etc. you will see a lot of "multi lane" passing, most less than 150' apart, and no separation by direction. I do try to keep to the right when I get into narrow or congested areas, but find a lot of others don't really seem to care about what side of the road they are on.

And then there is the "tunnel vision". It seems the faster some boats go, the narrower the forward field of vision becomes, something that can be a problem for the untrained driver at truly high speeds. Just as we get tunnel vision driving on the highway at high speeds (doing 80 and never see the cop in the median), the same thing can happen in the boat.

Just glad I can pick and choose my times to be out there, at least for the most part.