I have read dozens of threads and over a hundred pages on the forum. I have seen nothing stating what stats or upgrades help to repel boarders.
My highest lvl pilot was 28 on impossible. My latest pilot was a gun bunny with these stats at lvl 17 when he died.
Negotiate 3 Intimate 6 Tactics 6 Pilot 58
Ship custom made
Hull 13 Armor 8 Engines 40+11 Sails 27+4 Crew 58 Hold 95 Guns 7 Torp 16 Escape pod Bridge
A lvl 68 alien attacked me and I died on the 6th round. I had no issues with any non alien ship. I was hated by all factions. I killed every ship I encountered including alien until that one at 4x my lvl.
Any tips on repelling boarders? Retreat and ram has always failed against aliens that high in the past.
Well, the main stat that is defending against enemy boarding attempts is Pilot, which is put against enemy's warrior. Next you'd need something to negate their strength. Since aliens can have warrior even 125% of their level, it is nigh impossible to have a battle build that will repel boarding aliens that are 300% your level as you can see. The main stat that allows you to retreat while you're being boarded is tactics. But tactics are worthless ro have too high. There's only one reliable way to survive against the highest level aliens - become a boarder with ridiculously huge warrior, at least 150% of your level, and filling the rest of your cargo with weapons (since one weapon gives 3 bonus warrior) and since aliens never have anything else than 2 water-fuels, you may have an edge there. Intimidate is useless btw. and it is much better to focus on warrior and try to board them before they can board you. Helpful with leviathan (attack bonus based on warrior) or crew xeno suits (prevents damage to crew). Or there is a second option, become a torp build with high stealth. Torpers have one advantage over boarders - their build doesn't lose efficiency over time. Boarders do due to the fact that weapons cause diminishing returns. Also, torpers don't have troubles with ramming pirates. But I've lost countless alien hunters to these little jerks.