In case you need some ideas on what to do with a Zentraedi "Landing Ship" which, as we can see from U.S. Navy terminology is a very broad category.
Then you can use the "Craft" ideas to flesh out purpose built Horizont bunkers.
Taken from........
http://www.history.navy.mil/books/opnav20-p1000/l.htmLSB -- Landing Ship, Bombardment
LSD -- Landing Ship, Dock
LSH(L) -- Landing Ship, Headquarters (Large)
LSH(S) -- Landing Ship, Headquarters (Small)
LSM -- Landing Ship, Medium
LSM(R) -- Landing Ship, Medium (Rocket)
LST -- Landing Ship, Tank
LST(H) -- Landing Ship, Tank (Casualty Evacuation)
LSV -- Landing Ship, Vehicle
LSX -- Landing Ship Planned
LANCRA -- Landing Craft
LB -- Landing Barge(s)
LBE -- Landing Barge, Emergency Repair
LBE -- Landing Barge, Oiler
LBK -- Landing Barge, Kitchen
LBS -- Landing Barge, Support
LBV -- Landing Barge, Vehicle
LC or L/C -- Landing Craft
LCA -- Landing Craft, Assault
LCC -- Landing Craft, Control
LCC (1) -- Landing Craft, Control (Mark I)
LCC (2) -- Landing Craft, Control (Mark II)
LCE -- Landing Craft, Emergency Repair
LCEOP -- Landing Craft, Engine Overhaul Parties
LCF -- Landing Craft, Flak
LC(FF) -- Landing Craft, Flotilla Flagship
LCG(L) -- Landing Craft, Gun, (Large)
LCGM -- Landing Craft, Gunboat
LCGP -- Landing Craft, Group
LCI -- Landing Craft, Infantry
LCIDiv -- LCI Division
LCIFlot -- LCI Flotilla
LCI(G) -- Landing Craft, Infantry Gunboat
LCIGrp -- LCI Group
LCI(L) -- Landing Craft, Infantry, Large
LCILFlot -- LCI(L) Flotilla
LCI(M) -- Landing Craft, Infantry (Mortar Ship)
LCI(R) -- Landing Craft, Infantry (Rocket Ship)
LCM -- Landing Craft, Mechanized
LCM(1) -- Landing Craft, Mechanized, Mark I
LCM(2) -- Landing Craft, Mechanized, Mark II
LCM(3) -- Landing Craft, Mechanized, Mark III
LCM(6) -- Landing Craft, Mechanized, Mark VI
LCMSO -- Landing Craft Material Supply Officer
LCN -- Landing Craft, Navigation
LCOCU -- Landing Craft, Obstruction Clearance Unit
LCP -- Landing Craft, Personnel
LCP(L) -- Landing Craft, Personnel (Large)
LCP(M) -- Landing Craft, Personnel (Medium)
LCP(N) -- Landing Craft, Personnel (Nested)
LCP(P) -- Landing Craft, Personnel (Plastic)
LCP(R) -- Landing Craft, Personnel (Ramp)
LCP(Sy) -- Landing Craft, Personnel(Survey)
LCR(L) -- Landing Craft, Rubber (Large)
LCR(R) -- Landing Craft, Rubber (Rocket)
LCR(S) -- Landing Craft, Rubber (Small)
LCRU -- Landing Craft, Recovery Unit
LCS(L)(3) -- Landing Craft, Support (Large) (Mark III)
LCS(M) -- Landing Craft, Support (Medium)
LCS(R) -- Landing Craft, Support (Rocket)
LCS(S) -- Landing Craft, Support (Small)
LCS(S)(1) -- Landing Craft, Support (Small) (Mark I)
LCS(S)(2) -- Landing Craft, Support (Small) (Mark II)
LCT -- Landing Craft, Tank
LCT(5) -- Landing Craft, Tank (Mark V)
LCT(6) -- Landing Craft, Tank (Mark VI)
LCT(A) -- Landing Craft, Tank (Armored)
LCV -- Landing Craft, Vehicle
LCVP -- Landing Craft, Vehicle and Personnel
"Lion" -- A large advanced base unit consisting of all the personnel and material necessary for the establishment of a major, all-purpose naval base. It is made up of a large number of functional components which enables the base to perform voyage repairs and repair minor battle damage to a major portion of a fleet.