Hitting an anchored boat in a sparsely populated anchorage while under sail

[rslifkin]

Originally Posted by pjShap

I agree with the value explained by rslifkin for transmitting AIS at anchor. Never at a dock.



I've never been able to find that setting in my Garmin chart plotter. Does anyone know where it might be?

On most plotters I've seen there's an option in the menus for hiding unimportant AIS targets. You can usually set a minimum speed for display and a maximum distance for display. It may be buried in the settings menus somewhere.

[Jim Cate]

Originally Posted by TrentePieds

What causes otherwise sensible people to wish to use such information limiting technology as AIS for a job for which nature has equipped them with highly sophisticated and reliable means of handling that information?

Remember that at 5 knots, which we may take as "hull speed" for a 30Ft sailboat, the boat moves a boat length in four seconds.

You simply don't have time to mess with electronic devices if you are in confined waters, or waters where obstructions may be expected. Doing so impedes your ability to comply with COLREG #5. And if you are under sail, that compliance is already compromised!

TrentePieds

Umm... what causes otherwise sensible people to enter an anchorage at hull speed? Or to assume that one would be staring at a screen whilst actually entering the crowded area, rather than using the AIS data from a distance to see if there are any so equipped boats there or to initiate a VHF contact to obtain local knowledge?

Good seamanship practice is to use ALL available sources of info when evaluating a situation (as mandated by Rule 5), balancing them to suit the circumstances. I don't think that anyone upthread has suggested that one rely upon AIS to show an empty space in front of the boat. Eyeballs and radar are good for that phase... we all know that!

Jim

[Chotu]

Originally Posted by the stargazer

I was just kidding - making a joke about the 20 pages of off-topic AIS posts.

We know. It was fun to resurrect the (off) topic for a moment.

[OneBoatman]

Yes radar can be used to avoid collision hazards entering a sparsely populated anchorage. I have done this very thing while motorsailing we came into fog that quit quickly became a "pea souper", a term meaning zero visibility. You literally can't see the bow of your own boat. As this came upon us, I decided it was time to shorten the first day of a 5 day passage and approach an anchorage I was somewhat familiar with from many years earlier. Had I not taken the time earlier that same day to introduce a younger fellow sailing with me how to interpret the screen and shown him how to tune the sensitivity it would have been way to dangerous to approach the anchorage. I was pleased to find he was eager to learn how to use it and I knew that since my radar screen at that time was below at my chart table that should we encounter serious fog that would be important. Little did I know it paid off that very evening. Don't wait before sharing your knowledge with your crew because it may actually save your life. Radar has been important on a number of other trips. If you ply the waters of the Gulf of Maine, Nantucket Island Sound Buzzards Bay, Narragansett Bay, and Block Island Sound you will experience fog. We made the approach successfully but only because of that effort to teach another how best to help me. The next morning once the fog lifted, we learned he had had been correct the previous night in identifying and telling me that he had seen only one other vessel in that anchorage, and they were in fact there as proof on the hook at a safe distance from us. A proper captain doesn't simply decide to use the radar just before the critical need because he/she simply can't be looking ahead and at a radar screen at the same. That is not how the instrument is used. It shows its utility only if you take the time practice and pre-tune the range and clutter sensitivity ahead of the need so that when the time comes you are able to recognize a hazard with adequate time to react in concert with your vessels speed. If you have willing and able crew teach them ahead of the need. As far as hitting an anchored boat while "under sail" it carries the same responsibility sailing, under power, not under command, or adrift, and it has nothing to do with number of other vessels in an anchorage or not in an anchorage. AIS is used the same way, these instruments are great, but they are meant to be used to anticipate and identify danger and therein lies their preventative value.

[dwedeking2]

Lol. Few years before COVID I took a guy out sailing on his boat. When we came back in to pick up his mooring. He was unsure where to go, I said right next to the blue boat we left from. I looked over and he was staring at the gps. I said look around [emoji38]

[RaymondR]

A couple of decades ago my regular crew and I were seeking an anchorage in the dark using waypoints we had collected during a previous departure. He was on the wheel and I was monitoring the depth at the nav station.

During the pre entrance briefing I reminded him that the terminal waypoint placed the proposed course very close to a spur of reef and that he should maintain a 100 metre left-of-track XTE to ensure we cleared it. The nearest hazard to navigation on that side was about 1/2 a nautical mile.

He ran the vessel straight onto the reef achieving a stranded XTE of 0.00 nm. We agreed on a equal share of blame, he was at fault for failing to execute the agreed strategy and I was at fault for trusting him to do so??

[rslifkin]

Originally Posted by RaymondR

A couple of decades ago my regular crew and I were seeking an anchorage in the dark using waypoints we had collected during a previous departure. He was on the wheel and I was monitoring the depth at the nav station.

During the pre entrance briefing I reminded him that the terminal waypoint placed the proposed course very close to a spur of reef and that he should maintain a 100 metre left-of-track XTE to ensure we cleared it. The nearest hazard to navigation on that side was about 1/2 a nautical mile.

He ran the vessel straight onto the reef achieving a stranded XTE of 0.00 nm. We agreed on a equal share of blame, he was at fault for failing to execute the agreed strategy and I was at fault for trusting him to do so??

Personally, I would have wanted the waypoints placed such that following the plotted course with 0 XTE would keep the boat in safe water. It gives one less mistake to make.

[RaymondR]

Originally Posted by rslifkin

Personally, I would have wanted the waypoints placed such that following the plotted course with 0 XTE would keep the boat in safe water. It gives one less mistake to make.

Good practice---if you have a chart, we were in uncharted waters and uncertain of the whereabouts of the hazards which lay to starboard we were certain that there were no hazards for 1/2 nm or so to port.

The route built from the waypoints was the boundary over which the helmsman was instructed not to wander rather than the course he was to follow. The problem was that in his perception the island, 1/2 nm to port we were proceeding around was a greater hazard than running aground on the reef.

[Dockhead]

Originally Posted by OneBoatman

Yes radar can be used to avoid collision hazards entering a sparsely populated anchorage.. . .

Once you have become a good radar operator, it becomes your third and best eye.


I never enter an anchorage -- even in broad daylight -- without the radar on. Even if you can see it with your Mark I eyeball, you can't judge distance like radar does.

[sailorboy1]

Originally Posted by Dockhead

I never enter an anchorage -- even in broad daylight -- without the radar on. Even if you can see it with your Mark I eyeball, you can't judge distance like radar does.

you need to upgrade to the Mark II

[JPA Cate]

Originally Posted by sailorboy1

you need to upgrade to the Mark II

And what's that? post cataractectomy?

Love radar for the distance accuracy.

Ann

[Dockhead]

Originally Posted by sailorboy1

you need to upgrade to the Mark II

[alctel]

Yeah when I realised I could use my radar to measure the distance away from other boats when I was anchoring it was like a big lightbulb lit up

[Chotu]

that’s it! We finally have an explanation for what was happening

maybe these people were testing out their new radar. Trying to see if they could read the screen properly as they rocketed through the Anchorage at night with no lights on. Just to see if they could use the radar to avoid the boats that were anchored.

I guess they should have went to the remedial radar reading course before they hit the boat. Haha