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Comment by drewrv | Hacker News Reader

I understand that the terms are mostly unambiguous, but I always wonder how these get defined in edge cases. For example ferries, at least where I live, alternate the direction of travel as they go back and forth. There isn't a fixed "bow" or "stern" from which to define port and starboard.

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This is a great question imo but I struggled to find anything very good. I found a forum post, https://www.sailnet.com/threads/double-ended-ferries-which-e... and between the trolling it seems that fore/aft and port/starboard switch when the direction reverses, including eg navigation lights (red for port, green for starboard). And they tend to also have a one end and a two end or an A/B end, and those labels don’t change.

I've seen the 1 and 2 labels on barges near me.

I suspect they just don't use this terminology, unless it's to communicate with other vessels, and then it's presumably based on movement direction like you say.

Does that mean when you file a maintenance request they have to number everything on the ship since "aft 2nd floor" doesn't narrow things down much?

Spars and ribs (frame) are usually numbered, often based on distance, like interstate exits.

"Ten sequential rivets debonded on aft starboard #273 spar" would then be a writeup.

The Washington State ferry system uses double-ended vessels with a pilot house on each end with the crew swapping between them at each crossing. Whichever end the crew are at becomes the bow.[1]

Funny -- I've ridden the ferries a lot and never really thought about it.

1. https://www.sailnet.com/threads/double-ended-ferries-which-e...

Kirkland, WA resident here. There is signage on the boat that uniquely identifies the #1 end and the #2 end of the boat. Can be helpful in finding your way back to your vehicle if you drove onto the ferry instead of being a walk-on passenger.

The thing to remember is that those directions are used for an awful number of things that have nothing to do with the ship moving. Like when you name places for storing things or various pieces of equipment. Changing those names would create a lot of mayhem.

When I captain a boat it is more important for me to communicate things unequivocally. I need to be able to specify what I want to happen, precisely. The crew does not really need to concern themselves with the direction the boat is moving or what is the bigger plan. They just get orders to do specific tasks. Only I (or whoever is responsible for the boat at the moment) really need to understand the context of those tasks although ideally the crew would also understand why they are doing things so that they can anticipate further orders or signal when I make a mistake.

Why this is important is because the plan may sometimes change and then my job is to put a new set of orders and I can't really start by explaining what the new changed plan is or getting any consent.

I was never in a situation like that, but if I was captaining a boat that can change directions, I would still keep stable naming that does not change when the boat stops or changes directions.

Though, as it turns out, double-ended craft are defined by the direction they are operating.

I'm curious on other items that are defined in this way. Is does make sense that broad rules are lifted for obvious reasons. Is why I can name a few things where screw threading is reversed from what we typically use.

Those ferries should be switching the direction the crew faces (perhaps in a different structure on the other end of the boat) and turning on the appropriate lights so port and starboard are lit correctly. They should have two sets of colored lights to handle travel in both directions.

Don't they have to swap the lights anyway if the ferry reverses direction? After all, the red/green indicators are primarily for showing which direction the ship is moving in.

If I understand you correctly, yes, exactly.

With double ended ferries you're going to dock bow first because that's the direction all the cars pointed.

If you got halfway through a crossing and they announced there's a problem at the destination (broken thruster, docks on fire, dragons, docks on fire because of dragons), you would have to turn the ship around 180º and go back to your origin with the same bow that you started the trip with so everyone could disembark. The only time you'd switch ship orientation mid-trip is if something broke such that one end of the ship was navigable and the other was not. At which point you'd either have to dock backward (maybe with a tug) or everyone would have to back off the ship.

Cable/chain ferries would not be able to turn around of course, the drivers would have to deal with it.

Are there any cabled ferries that go beyond line of sight?

Depends on the time of day and the weather.

Well I'm pretty sure you can see a dragon attack at night.

P and S are really defined by the direction of travel or what you decide they are. They are just conventions.

The Torpoint ferry in Plymouth (Devon, UK) is on chains, so front and back, bow and stern etc is moot. I think we can simply redefine that sort of ferry as a fish and avoid any snags. That strategy seems to work for astronomy when trying to wrangle planet/dwarf planet/lump of stuff n that.

(EDIT: speling)

Oh great, now we will have flying ferrys.... or perhaps swimming planes!

https://www.youtube.com/watch?v=DgweA8tlh8Q

Bee fish! What a delightful idea. We do seem to insist on the weird when we elect officials in democracy lands. On the bright side we do actually get to elect these odd balls rather than have them dropped into place from above.

Back in the day, in England at least, otters were classified as fish too for the purpose of allowable nosh on a Friday for your discerning Catholic. Nowadays we munch on depleted cod stocks and chips. Yum!

How on earth that became a thing in a country where it is impossible to get around 70 miles away from the sea beggars belief. There are also rather a lot of rivers hereabouts but we don't generally munch on freshwater fish here either - WTF?

Ha! I thought of this in one of the down thread discussions. Very curious on any official answer here, and I'll have to pay attention to the lights on the ferry, next time I'm on it.

But they are on a fixed route…

For bidirectional ferries, I assume they just pick a direction all the way back at design time and stick to it.

The direction might not matter, but consistency does.

I’m fairly confident that the “bow” in that case is always the direction of travel in this case and that starboard/port side change.

The lighting scheme on ships indicates the starboard side with a green light and the port side with a red light. This allows ships to figure out which way another ship is heading - especially at night. If you can see the red light on the left and green on the right while facing the other ship it’s going away from you, if it’s reversed then it’s coming towards you. If you can only see green it’s going to your right, to your left if you can see red.

Retaining that property is important for navigation, so starboard and port have to swap sides.

Pretty much every boat with onboard motors are capable of reversing thrust. Do they all switch like that when traveling in reverse? (Serious question, not a boat person, never been on a boat that wasn't a ferry )

No, but you've already decided a direction that the bow points when using the word "reverse".

I don’t think boats travel in reverse very often because it’s inefficient to do so. If the boat is going in reverse, it’s probably docking, maneuvering, or having problems. In any of those cases, the crew should be situationally aware enough, and the boat slow enough, that they don’t need color-coded lights to keep themselves from causing a collision.

Steering can be much harder in reverse because the rudder is now at the wrong end.

“Normal” boats only go in reverse when they are maneuvering, never for extended distances and at travel speeds. Unless they’re purpose built they never travel in reverse - rudders are less efficient if going reverse, propellers are as well, and hulls are shaped to reduce drag when going forward.

You’ll basically only see boats going in reverse in harbors or exceptional circumstances. In harbors, speeds are generally low and extra caution is required of all ships. For exceptional circumstances, you’ll have special ways of communicating this - specific lighting patterns, flags, horns to warn others.

They can’t do it that way because the question of right of way only matters when two boats are going towards each other. The coloration is an easy visual indicator of where a boat is generally going that doesn’t require seeing any other part of the boat to work, and will even work in fog. You cannot safely flip the directions for any fraction of the boat’s travel.

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