If remember,my Iason Mk1 AU Landing support ship supposed to have an 127mm gun at bow to provide gun fire support in landing missions.In mid 1960's,when this LST was designed,RHN had replaced the 2 upper Mk38 5" gun in 4 Fletcher Class DD with Bofors ASW Mortar,so the guns were recycled in LST Iason Mk1.
Note that the Iason Mk1 has quite wide bow,like the WW2 LSTs.I imagine her something like an enlarged Terrebone Parish,but has more hydrodynamic hull shape underwater.The vehicle ramp which goes from front load deck to bow door, begins just rear of the crane.
Is possible to have a 5" gun at bow?
P.S Also in early 1970's,RHN had some double Mk38 5" from DD Allen M.Sumner,on which the Adis I launchers replaced the rear gun.The double Mk38 has similar weight with the OTO Melara 127/54C (about 37t vs 34t).Is possible to place an double Mk38 at bow?The ship designed to have a large 5" gun (designers had the OTO Melara in mind),but the Mk30 was a no cost option that era.
Below design has the Mk30 single 5"/38,upper the OTO Melara.