Report on yacht collision in Ireland in 2019 (report on findings)

[Dockhead]

Originally Posted by RUSTYNAIL

After a lifetime of being around the water and 42 years working for the USCG, I feel its time for all boats to be built to have a six mile radar image. Due to the curvature of the earth, that may be difficult for low profile motor vessels. My first wake up call to this problem was over thirty years ago looking for a friend’s 38’ sailboat north of Catalina Island, California (Santa Barbara Island). It was foggy. We got underway, and we had a radar to help him safely find a small anchorage. I couldn’t locate him so I asked my friend to bring up a frying pan after not finding him, and he lit up like a tanker. Bottom line, do you all know what your boat looks like without your radar reflector on a ship’s radar? Many radar reflectors are raised with a small line used for burgees. In a storm, the line can fail. The Moody should have lit up on the tanker’s radar many miles out if they had a radar reflector and the ship’s collision avoidance system should have alerted the tanker’s crew 20 minutes earlier. It’s not required, so the investigators can’t go after that problem. The international maritime groups should start mentioning permanently mounted radar reflectors as a cure for other potential collisions. I like fancy electronic devices, but I don’t trust the human factors in storms.

Problem is very few passive radar reflectors actually work. http://keyassets.timeincuk.net/inspi...ce_ym_june.pdf

If you want to be sure of being seen on radar, I think you need an active one. Something like this: https://www.plastimo.com/en/reflecte...tifs-9747.html

I think your best hope of being seen is to broadcast AIS.

[RUSTYNAIL]

Dock head...... I’ll never disagree with the effectiveness of AIS. It’s a great addition, I just cant imagine every sailor buying one, and keeping it working. I feel that sailing is one of the last freedoms that we have, and I’m not big into lots of regulations that are hard to enforce. I personally don’t care if someone sails around the world with kerosene running lights and no electricity, I just don’t want to run into him. There isn’t anything that works perfectly in every condition, radar reflectors do fairly well from my many experiences. I bought a new Simrad radar when I bought my boat, and it picks up sailboats without reflectors much better than the old radar.

[waterman46]

Originally Posted by Lodesman

He didn't actually give a current, just suggested that HW at Howthe suggested a northerly current, and that might have explained the pilots' 5 kt vs Varkan's 7.9 kt speed assessment of MM.

Good to have the local knowledge. Any idea what direction the current goes? Is there a current atlas of the region, or do the paper charts show direction?

Need to know if the two vessels were in substantially different currents. Not sure anyone can really know if the currents were different at the positions of the two vessels in the minutes before the collision. If current was actually running close to northerly, then it's likely the same for both. With both vessels in the same current, that current direction or speed would have no effect on the situation.

[Lodesman]

Originally Posted by waterman46

Need to know if the two vessels were in substantially different currents. Not sure anyone can really know if the currents were different at the positions of the two vessels in the minutes before the collision. If current was actually running close to northerly, then it's likely the same for both. With both vessels in the same current, that current direction or speed would have no effect on the situation.

I don't imagine the two vessels experienced a substantially different set - maybe the odd local eddy, but nothing from that front that would change the geometry of the meeting. The gist of my point, and previous to that Pete7's point was that speed reported can be very different based on perspective. For instance running with a 2 kt current means your AIS will say you're going 2 kts faster than what your paddlewheel knotmeter says. Depending on how VE had her ARPA set up, they could have been reporting relative water-speed or speed over the ground - this was not clarified in the report.