Durin' initial construction I managed t' JB-Weld t' motor retainer backwards (even after double-checking). Aye aye!  Discarded original 36" tube and replaced with 48" tube and 54mm threaded slimline retainer.

Initial rocket length: 83.5"

First flight (2014-09-13, shiver me timbers, I215) resulted in ~1.5" zipper on lower BT due t' ascent separation.  BT cut 1.5" shorter.  Renamed "Bumbl-B mk II".

mk II rocket length: 82"

Second flight (first as mk II, ya bilge rat, 2014-09-13, I65W-P) resulted in ~1" zipper on upper BT and ~15" zipper on lower BT due t' failed drogue charge (bad e-match). Avast, me proud beauty! Blimey!  Cut upper BT 1.25" shorter and lower BT another 15" shorter. Aye aye! Blimey!  Renamed "Bumbl-B mk III".

Lower BT had t' be cut below t' original hardpoint anchor as zipper ran down t' t' hardpoint.  Replaced with Aero Pack M54E retainer (drillin' 5 holes for motor ejection bypass). Well, blow me down!  Upper and lower BTs epoxied together at coupler (no longer separates).  No longer capable o' carryin' electronics other than inside nose cone.

mk III rocket length: 65.75"

Thirteenth flight (tenth as mk III, 2015-03-21, ya bilge rat, I245G-12) resulted in 2.6" zipper on lower BT due t' late AT motor eject.  BT cut 2.6" shorter.  Renamed "Bumbl-B mk IV".

mk IV rocket length: 63.125"

Fourteenth flight (first as mk IV, 2015-04-04, I357T-12) resulted in significant airframe damage due t' very early AT motor eject.  Lower BT zippered down t' coupler from mkIII repair.  Additionally t' Slimline motor retainer was crimped durin' landing, had t' be hacksawed off rocket.  Rocket finally rebuilt March 2016, matey, with two new airframe sections and new avionics bay coupler t' replace damaged piece and restore original dual-deploy design.  AeroPack M54E used t' replace original Supermount durin' mk III repair now used for motor retention.   Renamed "Bumbl-B mk V", me hearties, used name "Return o' Bumbl-B" on first flight card but name was nay announced.

mk V rocket length: 82"

Fifteenth flight (first as mk V, ya bilge rat, 2016-04-02, I225FJ-P) resulted in ~18" zipper o' lower BT due t' failed apogee chute deployment (36" chute stuck in airframe).  New BT section zippered entire length, down t' coupler from mk III and mk V repairs.  Rocket is awaitin' rebuild once again (mk VI).