I've tabbed this on a 5 string since theres no way I could down tune my 4 string to Bb,
but if your bass has heavy gauge strings then by all means! Unless you enjoy excessive
amounts of rattling lol.

Intro
Gb|-----------|
Db|-----------|
Ab|-----------|
Eb|-----------|
Bb|0------1-1-|X1

Pre verse
Gb|---------------------------------------------|
Db|---------------------------------------------|
Ab|---------------------------------------------|
Eb|---------------------------------------------|
Bb|010-000-000-0-10-000-000-010-000-000-44441111|X2

Verse 1
Gb|-----------------------------|
Db|-----------------------------|
Ab|-----------------------------|
Eb|-----------------------------|
Bb|000-000-01-0-0-0-01-0-0-0-141|

Gb|-------------------------|
Db|-------------------------|
Ab|-------------------------|
Eb|-------------------------|
Bb|000-000-01-0-0-0-11114444|

Play the verse twice.

Pre chorus
Gb|-----------------------------------------------|
Db|-----------------------------------------------|
Ab|-----------------------------------------------|
Eb|-----------------------------------------------|
Bb|0000000000000000-444444444444444-11111111111111|

Chorus - Twelves, tens, fifteens and thirteens
Gb|--------------------------------------------------------------------------------------|
Db|--------------------------------------------------------------------------------------|
Ab|--------------------------------------------------------------------------------------|
Eb|{7-7--22-3-33-33-33-10101010-8-8-8-8-8-8-8--7-7--22-3-33-33-33-10101010-8-8-8-8-8-8-8}|
Decide which you think is best
Bb|1212-77-8-88-88-88-15151515-10101010101010-1212-77-8-88-88-88-15151515-13131313131313-|

Verse 2 =
Pre verse X2
Verse X2

Chorus X2

Bridge
(A)
Gb|------------|
Db|------------|
Ab|------------|
Eb|------------|
Bb|0-(Let ring)|

(B)
Gb|--------|
Db|--------|
Ab|--------|
Eb|--------|
Bb|41000141|X1

(C)
Gb|---------------|
Db|---------------|
Ab|---------------|
Eb|---------------|
Bb|1-0--0000000000|

(D)
Gb|------|
Db|------|
Ab|------|
Eb|------|
Bb|1----4|

(E)
Gb|-----------------------|
Db|-----------------------|
Ab|-----------------------|
Eb|-----------------------|
Bb|1-0(Let ring)-000000000|

(F)
Gb|--------------------|
Db|--------------------|
Ab|--------------------|
Eb|--------------------|
Bb|1-0-0000000000-44444|

(A) X1
(B) X1
(C) X3
(D) X1
(C) X3
(B) X1
(C) X3
(B) X1
(E) X3
(B) X1
(C) X2
(F) X1

Final Chorus X2

Outro = Pre Verse once

Wow, sorry if the bridge is a bit confusing; I've labelled all of the different parts 
with a letter,
and then put the order it should be played in with how many times underneath.