I have a bunch of heavy lasers and missile turrets set up on the wall of the castle... It disposes of raiders pdq... Just watch the carnage if you can catch it and then go down to loot all the little bits and pieces of raiders spread all overs.
Well, when settlements started getting attacked i noted from which point the attackers were coming from and put in heaps of turrets.
Unfortunately my turrets were cutting the foes to pieces in no time but also doing damage to my improvements.
So I responded by moving and protecting the improvements.
The settlements were still being attacked but because of the number of turrets the enemies were being decimated in no time and i found it boring.
I responded by reducing the turrets to a bare minimum and putting in guard posts with armoured and armed settlers assigned.
Having large settlement populations made this possible.
For aesthetic reasons I placed enough guard posts so that some are permanently manned while some are visited periodically by patrolling guards.
As a result when attacks occur the settlers do most of the defending and the battles last long enough to provide me with some entertainment.
http://ocau.com/pix/3v7wc
http://ocau.com/pix/jvb4c
My highest defence is 100. Just because the Spectacle island is so large and it`s hard to find all spawining spots. In other settlements it`s usually equal water+food or a little bit higher.
I created a complex defence there with laser tripwires and sirens. So each time some enemies appear on the spot, the siren starts to work and all settlers run there. I made it mostly for fun..Just it`s fun to watch
No walls, just short fences which make enemies go some certain way and trigger the siren. Sorry, can`t add a picture , I don`t even know how to do it here.
People do it for the fun, as i do with guard posts.
I like to look at the defence structure from my elevated vantage point/luxury pad when visiting a settlement.
Realistically as soon as there is an attack the settlers auto respond.
The location itself is just really very large, so settlers can ignore enemies if they are on the other side of the island. I`v noticed it a couple of times, not sure, may be it was a bug. Probably, I could just add turrets , but I decided to try something new , so I created that thing with a siren. It`s really easy to create - you just connect a siren directly to a tripwire and switch the siren on. And the tripwire options should be set in a terminal ( to make it trigger only for enemies).
I also build guard posts. It`s nice to see my guards walking around. Makes the settlement look more alive.