Collision avoidance: being seen and heard

[pbryant]

I've skippered much larger vessels than the Ariel, and never had an issue with near-miss collisions. But since I began sailing an Ariel in the S.F. Bay, I've had dozens of close up encounters where I could tell the color of the other helmsman's eyes. I've had a few large motor vessels go by close enough that I'd be rolling 60 degrees in their wake and I could wave at the man at the helm (though not with all five fingers).

The scenario always plays out the same: the conflicting vessel speeds straight at my hull, until in the last 5 seconds before impact it veers sharply out of the way and passes close enough that I can see the terrified look on the helmsman's face.

My theory is: the Ariel has very little freeboard. Ordinarily, I consider that to be a good thing but - she looks small in the water. Human depth perception has an outer range limit of about 500 feet. The distance to anything beyond 500 feet is judged only by relative size. A vessel going 20 knots closes 500 feet in just 15 seconds. So people look to the Ariel and think: "look at that average-sized sailboat so far away. No problem!" When in fact, it's a SMALL sailboat really close up. Motorcyclists have the same problem - they present a near vertical profile and so other drivers lack visual clues about their distance.

So I've adopted the same survival strategy as motorcyclists: I assume I'm invisible and I go to extra trouble to make sure I'm seen and heard. I've installed a Kahlenberg Industries K-380 air horn to be heard. Here's a video of the horn in action while I was hove-to on a starboard tack taking in my mainsail. The video was shot with a wide angle fisheye lens and so objects are MUCH closer than they appear. http://www.youtube.com/watch?v=-GhAsNPUhWg

I've also installed red-over-green lights at the mast top conforming to navigation rule 25(c). I had to make the light myself, no one makes anything suitable. And if you look at the COLREGS manual under rule 25(c) you'll see a configuration with the green light down on the mast itself; which idiotically assumes you have transparent sails for it to been seen over all 32 points. I made mine out of PVC pipe and high intensity LEDs. Both the red and green all-around lights are above the masthead -- unobstructed by the sails.

I've also installed a Class B AIS transponder which has saved my vessel more than once. Here's a video where the conflicting vessel (a pilot boat) was hidden behind my jib while I was seated on the windward side. Once the AIS alarm went off (showing a "closest point of approach" of 0.00 miles) all I could see was a bow with lots of spray coming right at me. Without the AIS, I would have never been able to call the vessel by name on the radio and divert its course. Again, it's a fisheye lens and the boat is much closer than it appears. http://www.youtube.com/watch?v=DRHnm_mTVY8

I have since moved my boat out of the bay and thus gotten away from all the lunatic racers, who were the biggest offenders. I'm at Half Moon Bay now where I encounter mostly fishing boats that are professionally skippered and cruisers who are conscientious and competent mariners.

I love my Ariel, but one has to go to extra effort to avoid colliding with others out there on the water.

[ebb]

pbryant. He's reliant.
Start of a great thread. Thanks for the post and your equally informative
bluelines to your YouTube videos and text!

Did you take any photos of your LED fixture.....and how it's mounted?
Switching, wiring?
What AIS did you choose? Do you recommend it?
Your airhorn has a very nice sound - not at all expected (as I waited, watching the video)
What do you communicate with on the boat?

Moving objects on the water are really confusing to me. Too.
But moreso because I haven't spent much time at night on the water.
Or enough time even on the Bay during the day!
It a huge mental shift going from dock to deck.
Most confusing of all are the lights on the Bay at night.
where even stationary lights on shore seem to transit the water.



MNEMONICS BIBLE FOR BOATERS

Red over red. This boat is dead.
Red over green. Sailing machine.
Red over white. Fishing boat lights
Green over white. Trawling tonight.
White over white. Short tug/tow in sight.
White over white over white. Long tug/tow in sight.
Red over red over red. Rudder Rubbing Rocks.
White over Red. Pilot ahead.
Red over white over rad. Red When Restricted.

from "Definitions and Mnemonics for Sailors and Powerboats"
http://fmg-www.cs.ucla.edu/geoff/mnemonics.html
is a 12 page download by Geoff Kuenning of our complicated and often confusing
on water safety communication system.

[pbryant]

Thanks ebb.

Yes, I've posted a more detailed description on Sailnet with a somewhat fuzzy photo (reposted here as an attachment): http://www.sailnet.com/forums/gear-m...tml#post806167. The photo was taken at dusk. The LEDs are the newer high intesity type that make a lot of light for only 20 millamps each. They are very visble at night out to two miles (though they blend together to the unaided eye beyond one mile due to the only 1 meter vertical separation). I verified this by driving 2 miles from the harbor, and the lights were still clearly visible. They are brighter than my "2 nm" navigation lights.

I used the ACR Class B AIS transponder. It has worked reliably for nearly two years now. With an antenna at the masthead, I get solid coverage out to 30 miles and often see vessels with the higher powered Class A transponders and higher antennas out to 45 miles. I advise against using a VHF Radio/AIS antenna splitter, btw. I tried several and none performed well. A dedicated AIS antenna, even if it's below the masthead, performs better than using a splitter to try sharing the same antenna.

My radio is a Standard Horizon handheld model HX851 ($208 at The GPS Store). I have the charging cradle hard wired to the vessel's 12 volt bus. If the boat looses power, I still have about 8 hours of battery left. Although it's only 6 watts, power is less important than antenna height. I connect the radio's SMA antenna connector to my masthead antenna, and I use the optional external speaker/microphone which I hang in the cockpit when I'm underway. It's all capable of surviving immersion. The radio works great with range easily to 20 miles. The radio supports Digital Selective Calling (DSC) and has a built in GPS (one less connection to worry about). Sending a DSC distress call is simple and I've posted instructions for my passengers and always go over the procedure before getting underway. My motive is selfish - if THEY are using the radio - then something untoward has happened to me.

I have a Standard Horizon CPF390i chartplotter installed in the starboard cockpit bulkhead, which is visible in the videos. Connecting the ACR output to the chartplotter was simple - just two wires. Neither take much power: about 2 amps for both the transponder and chartplotter combined. I saved twice that much power by converting the navigation lights to LEDs.

I just recently installed a Vesper Marine AIS Watchmate (model 650) which has excellent filtering to display only the vessels that are a threat. It can filter out vessels that aren't underway and that are moving away from me. It also can display targets on a relative bearing, just like radar, and where they will be at the closest point of approach (if neither vessel changes course). It displays the full data (called "static data") for large vessels, including their destination, which can be helpful in anticipating their turns on course. There's a short demo video here: http://www.youtube.com/watch?v=LdmF0BaBz2U and a video that shows the decluttering ability of the display (with a traffic-congestion situation that looks like the SF Bay on a weekend - ugh!) http://www.vespermarine.com/video-aiswatchmate2/ . I got the Watchmate on clearance from West Marine for $95. So anyone not wanting to spring for a full-blown chartplotter may find that an attractive option.

[Lucky Dawg]

I sail in much less crowded (and apparently aggressive) waters! Still, I am curious where you mounted your air horn. Seems like a worthy safety feature to consider.

Yeow! That thing is impressive!



https://www.kahlenberg.com/catalog/p...products_id=79

[pbryant]

The horn placement took some trial and error experimentation. At first, I mounted the horns at the mast step. The jib sheets tried to strangle it and fling it overboard. I decided there were only two viable locations: all the way forward near the stem where I'd likely trip over them, or back on the cabin top near the turn of the top at the cockpit bulkhead where they are likely to make me go deaf. I opted for deafness over broken toes.

I ran an air line through a T fitting to the cockpit, and now I can also use the compressor to inflate my raft.

[ebb]

Deafning, maybe. But those 'bronze sounding diaphragms'.
makes going deaf..... mellifluous. Price to pay for style.
To keep lines off, the horns could be put in a nice ss wire cage instead of yacht tube.
Or inside a light weight box disguised as a dorade.

Wondered how you shopped for the right sound,
Do believe you chose wisely, really is a beauty.
But now that I've tested and compared all the horns on the Kahlenberg site,
I'm going with the O2M.
Warn the buggers off with rock and roll!

[Lucky Dawg]

HA! Mount it forward facing on the laz and let 'er rip.



Hear Hear, here https://www.kahlenberg.com/yankees.wav ...`a la Rodney Dangerfield in Caddyshack... http://www.youtube.com/watch?v=MVL4wKnpx2U

[ebb]

Kyle, How you find that????
And those look like a pair of Kahlenbergs in the Dangerfield cut.

Got to thinking,
pbryant not only amplifies his colregs
and expands the airboat
with that compressor on board.....
We've been using gasoline and diesel and lead/acid electrics
to put a hitch in our giddyup.
Isn't it time we came up with a compressed air auxillary???

Some may say that the O2M could be reversed facing aft
and mounted under the laz.....
No more splendid a gurgling sound of chromed power can be conceived.

But seriously: a compressed air motor needs looking into....
T off sometheing big enough to blow an Ariel through the water
and really blow up your dinghy.

[SkipperJer]

Accounts of a recent boating accident in the Chesapeake area made me realize how easy it is to go awry out on the water. I learned to sail during the mid-90's in Baltimore's Inner Harbor on J-22's. I didn't realize until a few years later how different my perspective on "right of way" is given my experience amid water taxi's, tug boats, small freighters, garbage skimmers, tour boats, and recreational power and sail boats piloted by skippers with varying level of experience out for a joy-ride. I have a number of assumptions that seem to work for me:

1. I pretend I'm invisible therefore the other boat won't ever see me. It's up to me to take action first no matter who's right.

2, Given that, it's in my best interest and my responsibility to see them first. I'm always facing forward and scanning left and right. I'm ducking under the sail for a peek often--very often--when sailing alone. With crew, I steer from the low side and watch under the sail and have crew scan the the open area. I had a "crash window" cut into my 150 to make this easier. I never sail alone at night. It's too hard to track what may be going on without at least two pairs of eyes, three is better. Electronic gear is neat for sure but designed for big boats that must "see" things at a greater distance since they lack maneuverability.

3. I have two working assumptions about what is going on in the other skipper's head. First, they've seen me (despite the fact that I'm invisible) and in their judgement, we will clear each other. In this case we have a difference of opinion and its on me to agree or change course. Since it's a free country I usually change course with malice toward none.

The alternative assumption is that the other skipper is busy with important crew well-being or boat operation tasks and is temporarily behind on their horizon scanning duties. OK. Stuff happens. We're all out here together. I'll help the other skipper out and change course. Here's hoping someone will do the same for me when we suddenly discover water above the floorboards or that we've run out of Cheetos.

4. I have all the required lights, flags, and safety gear. I assume the purpose of that is get me through an on-the-water inspection and keep me out of legal trouble in case there ever is a real collision followed by lawsuits. I do not expect any lights or gear to protect me or the other skipper in any way from banging into each other. No amount of signalling makes up for avoidance measures.

The result of this is that I make more small course adjustments than most even when out in the middle of the Chesapeake. One can also view this as being granted the opportunity to show off one's boat handling skills. I also seldom get ticked off or experience "fight or flight" adrenalin floods. I'm also inclined to think more highly of all the other skippers on the water which makes for more friendly conversations on the dock.

[ebb]

Skipper Jer, Such good points!

[Crazer]

I have found that when dealing with power boats, especially in confined spaces, it helps to assume that they will turn towards you ("try to hit you" just sounded a bit too harsh...) and give them enough space to do so and still miss. With alarming frequency, when I turned to avoid a boat, the other guy would turn in the same direction! It's just like driving, assume the worst, hope for the best.