Hundreds bound for Logan diverted to other New England airports yesterday because of a big ship blocking an approach to a runway

The ship doesn't have its phone number on the side like a taxi. ATC is in the 120s and Marine Radio is in the 150s.

If it was a tanker/cargo ship it was probably being tugged as well.

The ship wasn't big enough to create a ground stoppage. It had a ~150 ft mast which was told to the pilot on approach. Each pilot has to decide if it's safe to land for themselves or not. Besides, the fact that the initial plane being discussed went to MHT by diversion and landed before coming back to BOS suggests it didn't have the fuel to even come around and try again let alone going into an indefinite holding pattern until the ship fully passes the runway.

But the one thing I learned from the link below is the pilot can't rely on ILS landing (instrument-guided) when a tall enough ship is present. So, it's probably more likely a pilot isn't going to take as much risk if he's having to visualize everything for himself and not have the benefit of an instrument telling him how far off the path he is.

The story sounds normal for runway 4R at BOS.

https://www.thedrive.com/the-war-zone/bostons-airport-has-a-runway-where...

Flew to London in May. Red eye. Left Logan when we were supposed to be arriving at Heathrow. It did actually work out better for the time difference, but was not a fun night in the airport. Terminal E suuuuuucks.

And have TSA pre + global entry. Aside from that, it’s pretty brutal.

I got diverted to Manchester a few years ago (thunderstorm caused a giant backup at Logan). They didn’t want to let anyone get off at first, then let us walk around the terminal (although I think all the regular flights for the day were done, Dunks was the only thing still open). Surprisingly, after a few people pointed out they could practically walk home, they let anyone who wanted to go leave.
The flight to Logan was fun, took longer to taxi on either end than it did to fly. I was watching out of the window and guessed maybe Nashua after a couple minutes then realized we were already over Saugus.

Fog was also very likely a contributing factor, however you can go listen to the ATC archive from that night and ATC was indicating no ILS and a ship mast up to 135 feet in the channel for UA1150's approach (the tweet has a typo). Would have been a very specific glide path to get below the fog and above the mast without any auto-navigation, so it's very reasonable to do what the pilot did.

Perhaps he'd like a word with you. It's been a half century, but some lessons are best not learned twice.

4R is treacherous enough in the fog without a big boat changing the landing pattern dynamic. Although a big boat might notice that a plane crashed ...

Delta Flight 723

NY Times Article from 8/1/73

Basically, there are 6 runways at KBOS (Logan):
Two sets of paired runways:
4L/22R, 4R/22L
15L/33R, 15R/33L
And two singletons:
9/27, 14/32
They each have two numbers relating to their direction on a 360 degree compass and the direction you're approaching them (approximate to the nearest 10s and remove the 0, so 9 = 90 = facing magnetic East).

Only 2 of them are 10,000 feet long for the bigger, heavier planes: 4R/22L and 15R/33L. And between those two, 4R (the one that has the boat issue) has better taxiways for getting planes to pretty much all terminals. At the same time, you also need a runway for takeoffs too (you rarely route traffic to takeoff and land from the same runway for somewhat obvious logistical reasons). And you have to account for the wind direction.

So, given the poor weather condition at the time, longer is better (more time to see the ground and land before missing the runway). And the wind will matter even more to the pilot. So 4R was the longest, best chance at landing bigger planes in the weather even if it meant shutting off the IFR landing system for a small window while the ship passed through and forcing pilots into a harder landing situation...since they do have the option of leaving and trying again or going to an alternate city, refueling, and coming back to try again later.

And last, whatever you choose for routing the planes, you pretty much have to do for all of them because of having to coordinate landings and takeoffs on multiple runways (until you create a gap or there's a gap in schedule for changing approach vectors for the next planes). There were still other planes making landings on 4R with IFR off and the ship passing through.

There may be other considerations I'm not even aware of. I just armchair this stuff occasionally watching the radar, listening to ATC, and reading up.