What I noticed was, they didn't really seem to be focusing on you, had they been, they could have been done with you quickly enough. Had they had chaff, it would have made it much harder for you to hit with all 6 multicannons at all times. They seemed to be more occupied with the Vulture the whole time. Sure, you had a decent tank, but the Vulture is also very tanky and very maneuverable, you on the other hand are a boat when it comes to maneuvering and a bigger target. You likely could have been killed much faster than the Vulture and even though the Vulture is a bigger threat due to large weaponry, it's harder to kill in general, especially for ships bigger than it since it can spend a lot more time in their blind spots. Getting rid of you quickly would have left him by himself, leaving one of them to tank him while the other shot him down.
I'm confident had they been better with their tactics and perhaps with fittings, the fight would have been different. Gimbals are subject to less damage due to the tracking advantage, taking that tracking advantage away is a big deal when you don't get the damage of fixed weaponry.
On the other hand, in this situation, had you not gone all multicannons, you guys could have won the fight sooner since you were able to stay on either one of them for so long without even taking any damage. The Vulture was doing the tanking either via shield or maneuvering. There's no reason why the Vulture would be unable to stay on the Clipper with you so you both should have been able to eliminate him rather quickly. There's many ways this could have gone down, but due to tactics and loadouts, they got away after having killed your buddy.