I was unable to find a well-fitted bag for my H18 daggers... and the old bag I had was working on falling apart (dusting on the inside and tearing on the outside). After a decade plus, it owed me nothing. I couldn't find a vendor who still stocked a bag for the H18, though there are some nice Tiger dagger bags and plenty of Hobie rudder bags.
I searched around for something similar, using the dimensions from DVL: https://www.hobie.com/forums/viewtopic.php?f=13&t=7193
sixteen inches front to back, fourty eight inches up & down and about one & one eight wide.
I found a solution that works for me... Gator makes great soft road cases for a range of musical gear. I figured a guitar case might work for a Gibson Flying V (think of Eddie Van Halen's axe), but keyboard bags actually work better. I wound up ordering a Gator Case Light Duty Keyboard Bag for 76-Note Keyboards and Electric Pianos (GKBE-76), with 51" x 18" x 5" interior dimensions and about a 1/2 inch of padding all around. It comfortable fits a set of boards... and is still an acceptable fit for two sets of boards.
I would rather have sewn up a bag, but time and skills were short, and I wanted to protect the gear better for storage... so I spent an hour working Amazon. I hope this can be of use to other H18 sailors. I used a 76-key bag and I think the 88-key longer bag would work well for H20 52" daggers.
Randii (thought someone else might google this later)