After messing up 3 semesters, I need to average 67% percent in mech eng to get a 2.1.

I am an MEng student in Mechanical Engineering at a scotland uni, so it's a 5 year course.

3rd 4th and 5th year are worth 33% each.

I just finished first semester 4th year and I feel like I did very badly. I also messed up 3rd year. If my predictions are true, I would need to average 69% from here onwards to get a 2.1.

I really want a 2.1. Please tell me, how do I do this??

I've got my dissertation next semester, and it's all I do until the end of the year. Could I score very highly in that so I would only need, say, 67% in my final year?

The first step is to establish why you "did very badly" / "messed up 3rd year". Did you skip lectures/seminars and then not catch-up on the work? Did you leave coursework until the last minute, thus compromising its quality? Have you got the social life / academic life balance wrong? Are you just finding the work too hard? Was the some external factor which impacted you studies?
Unless something you're doing changes, it seems unlikely that your results will change.

Thank you for the reply. Truthfully I did find the content hard, and I found attending the lectures useless, but I would be caught up on everything within a month before the exams. I would always feel somewhat ready for the exams but I would end up doing really badly. I want to change (I NEED to change) but I really don't know what I'm doing wrong.

For context about 75% of the class miss lectures, if you go to one on any given day you'd struggle to see more than 10 people out of a class of 40, so I don't think it's that. I typically do decent in any assignments/reports, (60%+), but they're usually worth very little and don't really impact anything. It's all down to the final exams and I always end up messing them up. Do you have any advice? I don't think it's my personal intellect or anything, I think there's something I'm missing.

In the last month before exams I was studying at least 8 hours a day, honestly more than most in my class... but my grades don't reflect that

Clearly I'm not in best position to judge might be going wrong, so I just going to throw some things our there and see if any of them ring true:
1. You're targeting a 2:1, but are presumably just scraping a 2:2 right now if you say that "I would need to average 69% from here onward to get a 2.1." Is that about right? Does that put you around the middle of your cohort?
2. You say that "found attending the lectures useless". Why is that? Poor quality teaching? Do your lecturers just read through slides which you can access on-line anyway? Or do they struggle to explain complex concepts?
3. You say that, "about 75% of the class miss lectures". Can you spot anything different about the 25% who do attend? Do they tend to the the one who are struggling, and are hoping that attending lectures will help? Or are they the ones who are heading for a 2:1 or better?
4. You say you "would be caught up on everything within a month before the exams". So you give yourself a month for revision. How long did you allocate for revision for A levels? Or for end-of-year exams in Year 12? About a month too?
5. You say, "It's all down to the final exams and I always end up messing them up." Have you search the uni's web site (or elsewhere) for past papers, so you can see the types of questions that get asked? Would that help?
6. Does you uni offer any academic support, or similar?
7. Do you know anyone in the year above doing the same course? Perhaps they have some insights as to what worked for them.

Thank you for the reply.

Yes, I'm on like 51% percent right now, so I'm just about on a 2:2.

All our lectures get uploaded online, so I prefer to watch them in my own time/read the lecture notes, since I feel like the lectures in person are too fast paced. If I have any questions I end up emailing the professor anyway.

The people who do go are typically top in the class but there's lot of people on 70%+ who also don't bother going.

I'm not sure where I would be in the class but I probably would be below average.

After the disaster that was 3rd year, I decided to do all the past papers, sample papers, and tutorial questions for this exam series. (Last year they were very similar). But according to one of our professors the uni changed their policies so the questions are very theoretical now and not very similar to the past papers at all. This really threw me off since I based my prep on the tutorials/sample paper.

The good news is, there isn't many exams from now onwards- it's my dissertation next semester and group projects next year, along with only 2 exams. I usually do good in my coursework so am really hoping I can get 70%+ in my dissertation to try and fix this mess.

Do you think I have a chance of fixing this?

Given that you tend do to well in coursework, and that most of the remaining marks are from coursework / your dissertation, have you tried working out what your overall mark will be on the basis that you continue to do well in coursework? (So don't assume your average mark continues - as that's mostly from exams - but assume your coursework mark continues.) How close would that get you to a 2:1?

If I take an average of my reports/assignments it'll be about low to mid 60%. which is still obviously less than what I need but miles closer than the 51% I am now

OK. So if just performing as you already have been in reports / assignments gets you to low to mid 60s overall, then attaining a 2:1 is certainly achievable by improving some of those results.