Minefields

Ships with torpedoes can convert their torpedoes into spacemines by using the "Lay mines" mission. Minefields are generally used as a defense against enemy ships. Minefields are laid in a circle centered at the position of the minelaying ship before movement. There can be a maximum of 500 minefields and web minefields in the universe. A ship needs to have fuel onboard to lay mines; minelaying itself does not burn fuel.

When laying a minefield, a ship will nicely send it's owner a message informing him of this action:

Amount of mines laid
The amount of mines laid depends on the number of torpedoes used and the type of the torpedoes.
The formula is mines = torps * torpslot^2, where the value for torpslot is a number ranging from 1 to 10.
Note that the term used is "torpslot" and not "techlevel".

Robotic minelaying advantage:
The Robots have a special ability, they convert torpedoes into four times as many mines as all other races.

This results in the following table:

Size of minefield:
The mines are laid in a circle, the radius of which is the square root of the number of mines, truncated.
Per default (host-configurable) the minefield radius may not exceed 150 lightyears. Attempts to lay bigger minefields will result only in a maximum-sized minefield, no torpedoes will go to waste.

Example: 10 Mark 8 Photon torpedoes laid as mines would result in 10*10^2=1000 mines, which would result in a circle with a radius of 31 lightyears (the square root of 1000 is 31.6, which is truncated down to 31).

Controlling the size of a minefield:
Using friendly codes a ship can lay only part of it's torpedoes as minefields, saving torpedoes to lay as mines somewhere else or to fire at enemies later on.
The friendly codes are:
"md1" - drop 10 torpedoes as mines
"md2" - drop 20 torpedoes as mines
    etc, etc, etc....
"md9" - drop 90 torpedoes as mines
"md0" - drop 100 torpedoes as mines
"mdq" - drop a quarter of all torpedoes in cargohold as mines (formula: trunc[mines/4])
"mdh" - drop half of all torpedoes in cargohold as mines (formula: trunc[mines/2])

Laying mines in another race's identity:
It is possible to lay mines in the identity of another race, using a friendly code of "miX" where X is the number of the other race (1 for Feds, 2 for Lizards, .... a for Rebels, b for Colonies).

Overlapping minefields
Usually, to create overlapping minefields simply make sure the center of a new minefield is outside any existing minefield. This way, if the minelaying ship is close enough to an existing minefield so that the radius of the new field is greater than the distance to the existing field, the fields will overlap.

When laying mines inside an existing minefield, the mines will usually be added to the current field. In some cases however a new field will be formed.
To determine whether to add to the existing field or to form a new field Host follows these steps:

1. Find the minefield of which the center is closest to your ship.
2. If you are inside this field you will add to it.
3. If not, you will lay a new minefield.(regardless of whether you're inside any other minefield(s))

Note that minelaying is done in ID order (lowest to highest) so you need to factor in the actions of lower ID ships (lay/add/scoop) in the same turn first. If your ship is inside a large field but actually closer to the center (but not inside) of another, smaller field, Host determines that your ship is outside of that small field and will create a new one. It does not matter that you're also inside another large field.

Concentric minefields
Under normal circumstances, laying concentric minefields (centers of different minefields are on the exact same location) is impossible, unless a player lays mines in the identity of an ally. The Crystallines however have an "ability" to lay concentric minefields all by themselves. This ability holds true up to Host 3.22.025 and is considered a bug by Tim, so will likely be removed in more recent versions of Host.

It is possible for the Crystallines to lay a webmine and a normal minefield centered on the exact same coordinates. So far, nothing special. Both the web mine and the normal minefield each get assigned a certain ID number. This too is perfectly normal. If however the minefield gets assigned a higher ID number than the webfield, any regular mines laid at the the same coordinates as both the minefield and the web will result in a new, concentric minefield. If the minefield has an ID lower than the webmines normal rules apply: extra mines are added to the minefield.

The Crystals can use this "ability" to help their allies, too. This mechanic works not only with Crystalline webmines but with all web mines.

Minefield friendly code

Every minefield and web minefield has a friendly code, which is the same friendly code as the closest planet of that race (measuring the distance from the centre of minefield to the planet). If the owner of a minefield does not have any planets left, the minefield does not have a friendly code.

Any starship with a friendly code matching that of the minefield would be able to travel through the minefield and not hit any mines. If the planet's friendly code is changed the minefield's code will change to match it. The minefield friendly code takes effect as soon as the mines are laid and changes anytime you change the friendly code of the planet controlling the minefield. Web mines do not drain fuel from ships with matching friendly codes, and (web)minefields cannot be swept by ships matching the field's friendly code.

The minefield friendly code system follows these three rules:

1. Minefields have friendly codes. The minefield's friendly code will be the same code as the planet that is owned by the owner of the minefield that is nearest the mines centre. So if you laid a minefield at Nixon and you own Nixon and Nixon's friendly code is "Q1m" the minefield would have a code of "Q1m". Any starship with that friendly code would be able to travel through the minefield and not activate any mines. If the planet's friendly code is changed the minefield's code will change to match it. The minefield friendly code takes effect as soon as the mines are dropped.
2. A planet with a friendly code beginning with "mf" will cause ALL minefields belonging to your race to have this code as the minefield universal friendly code. If you set more than one planet's friendly code first two letters to "mf" the highest ID planet will be used to set the minefield universal friendly code. The character following "mf" can be any letter or number. Example: If one of your planets friendly code is set to "mfK" then all your minefields will have the universal friendly code of "mfK".
3. A ship can use rule 1 or rule 2 to safely pass through a minefield. Both rules are in effect. The ship can use the "local" friendly code or the "universal" friendly code.

   Example: If a Birdmen ship using the Super Spy Deluxe mission tries to set the friendly code of any enemy planet to a code beginning with the letters "mf" and the planet has more than 30 defense outposts the planet will always use an Ion discharge overload to knock the ships out of cloak.

Minefield decay, mines destroy mines

Each turn, a set percentage of mines are destroyed from each minefield. The host-configurable percentage is 5% by default for both mines and webmines. After this percentage is deducted, one additional minefield unit per turn is destroyed through natural causes.

If after the natural decay two minefields of different races that are not allied are still overlapping, they will blow eachother up. This happens if  two minefields are in any way overlapping eachother. If the radius of the first field and the radius of the second field together are larger than the distance between the fields' centers, mines will destroy mines. When mines destroy mines, an equal amount of mines is destroyed from both fields until either one of the fields or both are totally blown away. When multiple minefields overlap eachother, mines destroy mines in order of minefield ID number. First the lowest ID reacts to the next lowest, and so on.

Overlapping web mines never destroy eachother, regardless of alliance settings between the Crystals and the other races in whose identity the Crystals have laid the other webs.

Minehit damage

Enemy ships travelling through minefields, unprotected by matching friendly codes or an alliance, run a risk of 1% to hit a mine for every lightyear travelled. Cloaked ships run a risk of 0.5% per lightyear (both numbers are host-configurable). The chances of hitting a mine are calculated per lightyear, and the chances are cumulative. For example, a normal ship has a 99% chance per lightyear to NOT hit a mine. For 40 lightyears, it's chance not to hit a mine is (0.99)^40 = 67%. In other words, the ship runs a chance of 33% to hit at least one mine.

A ship that hits a mine will suffer a certain amount damage, depending on the ship's mass. The formula used is Damage = 10000 / (mass+1). It is possible for ships to hit multiple mines in one journey.

Ships with a hull tech level below 7 (this is host-configurable) will slow down immediately after hitting a mine: their waypoint will be set back by 10 lightyears if it has more than 10 lightyears to travel when it hits the mine.

If a cloaked ship hits a (web)mine and the amount of damage it suffers is greater than the amount of damage that prevents cloaking, the ship will be immeadiately decloaked - even if it has enough supplies to repair the damage. Because of this, it has a higher chance of hitting a second mine after it has hit the first mine (the rest of the journey it runs the chance per lightyear for uncloaked ships, while earlier it only ran the chance per lightyear for cloaked ships).