i had nice success today building a circle of ied ' s around the poinsonship with 1 hex distance from the ship itself and some mines were in there too . the negative side is all scythers evaporated . and the ai core was damaged down to 10 %. however if you want to be a bit cheaty you can build walls close around the ship except one side and build double or tripple the amount of ieds there depending on the number of mechs you expectoh and to set the whole thing of a sniper rifle suffices . if i do not have enough components for ied ' s . then emp grenades are a must before triggering the ship at close distance with a good sandbagcover never forget to jug en emp first . it gives you enough time to kill a ecent amoung especially early in the game when only a few mechs span you can win without wounds . of course triggering with mortars and then make your stand at your base entrace is also an option , however you need to hit quite a few times with the mortars until they attack . the wall building oventrick does not work very well btw , i tried . 220 C does not damage them fast enough before they dig trough the walls , even if you repair the walls