Vision and distance?

[Aleolus]

OK, so my PCs are going to be coming to my island port city soon. The first thing that comes into view is the most impressive landmark in the city, a massive tree, about 400 feet tall, which is about four or five miles inland. My question is, how close to the island would you need to be before that would come into sight? I'm pretty sure it would be visible before any of the rest of the island, but I have no idea how long it would be in sight before the rest of the port would be visible.

[Doctor Despair]

Technically depends on how large the planet is and what shape it is.

[PoeticallyPsyco]

Okay, a quick check over at Wikepedia gives the formula for when something becomes visible over the horizon (assuming a roughly Earth-sized planet):

Distance = 3.57 * ( sqrt(height of viewer) + sqrt(height of object))

Where the distance is in km and the heights are in m.

So the top of a 400ft (122m) tree would be visible from the deck of the ship about 45 km (28 mi) away from the tree, or 37-39 km (23-24 mi) from shore.

If we assume it's recognizable as a tree once you can see half of it, you'd be able to recognize it about 35 km (22 mi) from the tree.

OTOH, a quick google search suggests a crow's nest is about 35m (115ft) above sea level. If the players/crew are looking from that high, they'll first see the tree 60 km (37 mi) from the tree, and recognize it 49 km (30 mi) from it.

[Aleolus]

Basically the same dimensions as Earth

[martixy]

Okay, a quick check over at Wikepedia gives the formula for when something becomes visible over the horizon (assuming a roughly Earth-sized planet):

Distance = 3.57 * ( sqrt(height of viewer) + sqrt(height of object))

Where the distance is in km and the heights are in m.

So the top of a 400ft (122m) tree would be visible from the deck of the ship about 45 km (28 mi) away from the tree, or 37-39 km (23-24 mi) from shore.

If we assume it's recognizable as a tree once you can see half of it, you'd be able to recognize it about 35 km (22 mi) from the tree.

OTOH, a quick google search suggests a crow's nest is about 35m (115ft) above sea level. If the players/crew are looking from that high, they'll first see the tree 60 km (37 mi) from the tree, and recognize it 49 km (30 mi) from it.

https://www.wolframalpha.com/input/?i=horizon+distance

[Aleolus]

...OK, now next question, of the ships talked about in Chapter 5 of Stormwrack (pg 97+), which one would be closest to your typical overseas merchant vessel? I'm leaning towards a Galley, but it says that those are typically military ships, so I'm not sure.

*EDIT* I am trying to figure out how long it will be after it comes into sight before they come into port, mostly. Assuming light winds.

[InvisibleBison]

...OK, now next question, of the ships talked about in Chapter 5 of Stormwrack (pg 97+), which one would be closest to your typical overseas merchant vessel? I'm leaning towards a Galley, but it says that those are typically military ships, so I'm not sure.

*EDIT* I am trying to figure out how long it will be after it comes into sight before they come into port, mostly. Assuming light winds.

This depends on the type of ocean. In relatively placid inland seas, galleys' ability to travel independently of the wind is very advantageous, and most merchant ships will be galleys. I'd probably use the trireme for the typical merchant galley; you're right that the ship labelled "galley" is really a dedicated warship. In more open and stormy oceans, however, the galley's lack of seaworthiness precludes its use. Here, you'll see cogs and caravels as the main merchant ship.

[PoeticallyPsyco]

...OK, now next question, of the ships talked about in Chapter 5 of Stormwrack (pg 97+), which one would be closest to your typical overseas merchant vessel? I'm leaning towards a Galley, but it says that those are typically military ships, so I'm not sure.

*EDIT* I am trying to figure out how long it will be after it comes into sight before they come into port, mostly. Assuming light winds.

In D&D, the caravel is considered the "default" ship. If that's too strong (and it is one of the better ships) to be handing out to every merchant, maybe the dhow?

[PraxisVetli]

Okay, a quick check over at Wikepedia gives the formula for when something becomes visible over the horizon (assuming a roughly Earth-sized planet):

Distance = 3.57 * ( sqrt(height of viewer) + sqrt(height of object))

Where the distance is in km and the heights are in m.

So the top of a 400ft (122m) tree would be visible from the deck of the ship about 45 km (28 mi) away from the tree, or 37-39 km (23-24 mi) from shore.

If we assume it's recognizable as a tree once you can see half of it, you'd be able to recognize it about 35 km (22 mi) from the tree.

OTOH, a quick google search suggests a crow's nest is about 35m (115ft) above sea level. If the players/crew are looking from that high, they'll first see the tree 60 km (37 mi) from the tree, and recognize it 49 km (30 mi) from it.

I feel like you shouldn't need to see half of it to recognize it unless the other trees near it are also 400' tall.

[Psyren]

You could probably find statistics for similar landmarks, like the Statue of Liberty, and how far out before they become visible by telescope, binoculars, naked eye etc.

(Similar in the sense that they're coastal landmarks you'd be looking for when coming into a port via ship, not necessarily in terms of size - you'd want to find such a landmark with similar dimensions to the one you're doing.)

[Kelb_Panthera]

Guidelines in stormwrack suggest you should be able to spot it from 25-50 miles out if you've got somebody in the crow's nest of your ship. Half that if they're just standing on the deck.