I've recently started experimenting with Polyurethane. It allows me to do a few things that wood doesn't so I decided to tweak the Undertaker. I'm super please with how it came out and its a big change to the original.
#1: I added a Buoyancy Control Chamber so the lure can be be changed from suspending (the default) to either floating or to various sink rates, in under a minute.
#2: I managed to increase the glide length by making a few small tweaks> Changed the swim from a tight wiggle to a nice 3 foot glide.
#3: I increased stability by adding a small back spoiler (removable/replaceable). That further increases glide length and it can be worked at high speed.
#4: Getting further UNDER, a combination of the increased glide and stability allows the Undertaker to get around 2m under cover.
There are a few other positives, like being able to fish it Twerk Style or even Butch Brown rig it, but getting it under cover is the main design feature of the Undertaker. I wanted something to swim deep into floating cover, to where the big girls live unmolested by most lures.
The wooded Undertaker has given me a few PBs and I have very high hopes for the new improved version.
https://www.youtube.com/watch?v=zzsczInuuP4