Overt defenses
A stripped out powerplay hauler optimised for cargo capacity is the essentially same build as a greedy trader, and will be similar to a mission rather than survive-ability optimised vessel, and they are all guaranteed to see their rebuy screen. When I used to hunting powerplay fortifiers, I'd carry a mix of fixed and gimballed weapons, some loadouts I'd have gimballed lasers and fixed kinetic weapons - usually huge cannon under the nose of an FDL, others would fixed lasers and gimballed kinetics - usually multicannons. Reason for the split is lasers and rails shoot line of sight, where projectile weapons have a requirement to shoot ahead of the target, and its annoying to not be able to shoot both at the same time. This loadout gave me an advantage in that I could alphastrike, ie fire everything at once - and hit target, however it also brings with it a vulnerability to chaff, if the target popped chaff that would effectively deny me half of my weapons systems.
While I could detarget them to shoot gimballed weapons through their chaff cloud as though they were fixed, it requires me to be pointing the ship in a direction that only one weapons system will work. So for example if I start manually walking the multicannons onto the target ship, my lasers would be shooting across the targets bow completely ineffective on target, or if I focussed on using the fixed lasers, the multicannons are going to miss them by miles as the gimbal either dances like a python in a basket to a flute, or if I detarget the ship, they will shoot straight ahead and because of the ballistic arc, they will be raining down on the empty space behind my quarry.
So in summary, chaff can be a major inconvenience to SOME loadouts hostile players might be flying, and as such chaff is definitely worth a utility slot or two. Two chaff effectively allows perma-chaffing, just keep spamming chaff to annoy your enemy by making yourself harder to shoot at.
Another tip for surviving gankers, is donot faff about trying to low wake back to SC, highwake to another star system, reason being highwake is not affected by mass lock factor. If I pull you out of supercruise and you are flying a dropship, and I'm in python, my MLF is 17, yours is 14, if you try to low wake out of that encounter, due to my MLF I'm going to make it take 17*5=85 secs for you to charge your FSD, but if you highwake out the FSD only takes 15sec to charge, even if I were flying a cutter with 27 mass lock factor. And the bigger the ship pulling you over, the longer they can keep you there, the easier it is to kill you, so always always always highwake when retreating.
Flight assist off - some players, like me, fly with flight assist off all the time, it is harder to fly this way, but it is very rewarding and has a lot of advantages that warrant a conversation of their own. However for the victim of a ganker, even if they havent mastered the ways of the force and thus how to fly FAoff, while wriggling for their life trying to evade incoming weapons fire and charge their FSD to (hopefully high) wake out, toggling FAoff can help. With FA off for every input you give your ships flight controller, say vertical thrusters up, it will continue to keep doing that motion until you put a counter input in, ie vertical thrusters down. So for an example sequence of FAoff manouvers to make you a harder target for your ganker to hit, boost while using laterals and vertical thrusters and immediately hit flight assist off, you are now going to be travelling along a vector, its exact direction doesnt matter. You then, while still having flight assist off "steer your ship" (yaw pitch or roll or a combination of them all) , but because flight assist is off you are still going in the same direction in relation to space, even though your ship is now pointing a different direction. At that point re engage flight assist and boost, your ship is now travelling on a new vector, the direction you are pointing in, which could be at a large angle to the direction you were drifting a second ago. This plays havoc with any enemys attempts to garget you, especially with weapons such as plasmas where they need to shoot ahead of your ship to compensate for the travel time of their projectile. If you are now travelling 90° to the direction you were going when they released the shot, their shot could miss you by hundreds of meters of not a full click.
Stealthy defenses
If you lose your shields while trying to escape, dont panic about it, embrace it and repeatedly toggle silent running on and off. this will break the target lock your foe has on you. Only a couple of seconds silent running on, then back off for another couple of seconds, repeat makes you harder to hit. This is compounded if you are still twisting and evading, as you will appear on and disappear from their scanner as you toggle this on and off.
Heatsinks are a great use of a utility slot if trying to hide, pop a heatsink you get so cold you drop off their scanner. Go one better, go silent running and a heatsink when temp starts to get toasty, you will have thus been off their scanner for a while.