Can anybody explain Home port combat bonus?

[Rongor]

According to the manual, we have that zone with a radius of 3 hexes around a home port, providing a combat bonus for our units.

Does the exact combat bonus in any way depend on the distance between the unit and the home port hex? Is a unit right in the home port hex gaining more bonus than one adjacent to the home port and much more than a unit in the outer 3rd hex ring?

I used to park ships in that outer (3rd) hex ring often, to protect more seazones in front of my home port, still gaining the combat bonus and thus keeping them relatively safe and protected.
Now I had two occasions in which I suffered severe losses while doing this.

In an MP game, I had my German Hochseeflotte in the German Bight, protecting my coast of the North Sea. I distributed my ships onto the 3rd ring, just inside the home port bonus zone. The Entente opponent arrived with the Royal Navy and he later told me he was also surprised to see remarkably balanced combat odds predicted. So he tried his luck and took out even battleships. The Royal Navy didn't receive any higher damages, there was no sign of a combat bonus benefiting my units at all. I can tell you, this left me "wtf this is impossible!" At least as far as I understand the rules, it should be impossible.

Then I had it in a SP game, playing the Entente. I parked an armored cruiser or the size alike in that outer green marked seazone at the northern approaches of the English Channel. Now three German Battleships arrived and vaporized my unit. None of those three attackers took any damage. So where was the combat bonus here?

Does the combat bonus shrink gradually from port to the 3rd hex ring? Even if so, how can it feel like there is no bonus at all when staying in that 3rd ring?

Note that in both occasions the attacker ships were outside my bonus zone. May this play a role? Does the bonus apply only if the attacking unit is attacking from a position also inside the defenders home port bonus zone?

Many questions, hopefully someone can bring some light into the dark.

The manual says

Naval units within four hexes of a friendly port receive a combat bonus.

Reads very simply but obviously doesn't work that simple.

[Rongor]

two pics showing an engagement clearly in my zone:

Where is the decent combat bonus? is the balancing of different equipment levels all I receive?

[operating]

Don't hold me to this: I remember reading something Kirk wrote that said something like this when v1.64 was released: "That a defending fleet get's 30 points added to a fleet's defense rating while in port". So if a fleet had a regular defense rating of 48, it would now be 48 + 30 making it a combined defense rating of 78 while in port. Take note, that is only for defense rating points, "Not offense", it does not increase the naval attack rating, however, more than likely if the port is surrounded by favorable green dot hexes (not all ports do), then there would be a bonus added to attack value of your fleet if you own the port. Have noticed where sometimes a fleet get's stuck in a port of a former ally that has surrendered and gone neutral, that fleet stuck in port does not received any of the port's defense rating.

[Rongor]

yes, the bonus is lost instantly when the port city gets lost.

What struck me by surprise was the vulnerability outside the very port hex but inside that "green zone". Manual and the green map symbology sell it as some sort of a "pretty safe zone" which it apparently is not.

[operating]

Been Looking into the lua files about the 3 hex port defense zone of green dots. I've only come up with this so far (will keep looking):

function HasHomeSupport(alliance, hex)
local portSupportRange = 3

local hexes = game.map:GetHexesInRange(hex, portSupportRange)

for _, portHex in pairs(hexes) do
if portHex.construction ~= nil and portHex.construction.type == Construction.TYPE_PORT and portHex.construction.city.hex.originalFaction.alliance.id == alliance.id and portHex.construction.city.hex.faction.alliance.id == alliance.id then
return true
end
end

return false
end


function HasPortSupport(alliance, hex)
if hex.construction ~= nil and hex.construction.type == Construction.TYPE_PORT and hex.construction.city.hex.faction.alliance.id == alliance.id then
return true
end

return false
end

function DamageEfficiency(unit, damage)
unit.efficiency = unit.efficiency - damage
if unit.efficiency < 0 then
unit.efficiency = 0
end
end


function GetEnemyAlliance(alliance)
return game:GetAllianceById(3 - alliance.id)
end

[Rongor]

so I would read it as efficiency being equal the strength. But what is efficiency exactly?

Btw, where do I look stuff like this up?

[operating]

Click OS (then double click others); OS/Program files(x86)/Slitherine/Data ....to get started, then you can explore all the different files from there.

[Rongor]

wilco, thank you!